11 Special instructions

This instruction is to complete the PID operation and is used to control the parameters of the closed-loop control system. PID control has a wide range of applications in mechanical equipment, pneumatic equipment, constant pressure water supply and electronic equipment, etc. among them:

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[[image:11_html_1c6bb88c06ac24cf.png||class="img-thumbnail"]] is the target value of PID control;

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[[image:11_html_fb5122fb6e3a43d5.png||class="img-thumbnail"]] is the measured feedback value;

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[[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]] The starting address of the buffer area for setting parameters required for PID operation and saving intermediate results, occupies a total of 26 variable units in the subsequent addresses, the value range is D0 to D7974, it is best to specify the power failure retention area, which will remain after the power is OFF Set the value, otherwise the buffer area needs to be assigned value before starting the operation for the first time. The function and parameter description of each unit are described in this section;

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[[image:11_html_b126b1b2673dc1f4.png||class="img-thumbnail"]] is the storage unit of the PID calculation result. Please designate [[image:11_html_d47cd1f59b766ed3.png||class="img-thumbnail"]] as a non-battery holding area, otherwise it needs to be initialized and cleared before starting the calculation for the first time.

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**Programming example**

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47

[[image:11_html_888504306151fa15.png||class="img-thumbnail"]]

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The parameter description is as follows:

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What is stored in D9 is the target value of PID adjustment, and D10 is the closed-loop feedback value. Note that D9 and D10 must be of the same dimension, such as both 0.01MPa units, or 1℃ units, etc.;

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A total of 26 units of D200 to D225 are used to store the set value and process value of PID operation. These values must be set item by item before the first PID calculation;

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The D130 unit is used to store the calculated control output value to control the execution of the action.

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The function and setting method of the parameter value of each unit about starting of [[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]] are described in the following table:

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|**Unit**|**Features**|**Setting instructions**

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|[[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]]|Sampling time (TS)|The setting range is 1 to 32767 (ms), but it needs to be greater than the PLC program scan period

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|[[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]] +1|Action direction (ACT)|(((

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bit0: 0 = positive action; 1 = reverse action bit3: 0 = unidirectional; 1 = bidirectional

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bit4: 0 = auto-tuning does not work; 1 = auto-tuning is executed, others cannot be used.

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)))

67

|[[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]] +2|Maximum ascent rate (DeltaT)|Setting range 0 to 32000 is the threshold of integral increment

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|[[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]] +3|Proportional gain (Kp)|Setting range 0 to 32767, note that this value is enlarged by 256 times, the actual value is Kp/256

69

|[[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]] +4|Integral gain (Ki)|Setting range 0 to 32767, Ki=16384Ts/Ti, Ti is the integral time

70

|[[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]] +5|Differential gain (Kd)|Setting range 0 to 32767, Kd≈Td/Ts, Td is the derivative time

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|[[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]] +6|Filtering (C0)|Setting range 0 to 1023, integral part filtering

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|[[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]] +7|Output lower limit|(((

73

Recommended setting range -2000 to 2000

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{{id name="OLE_LINK630"/}}When bit3 of S3+1=0, set to 0; When bit3 of S3+1=1, set to -2000;

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)))

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|[[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]] +8|Output upper limit|Recommended setting value 2000

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|[[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]] +9|Reserved|Reserved

79

|︙|︙|︙

80

|[[image:11_html_6c3fad4a32a3db43.png||class="img-thumbnail"]] +25|Reserved|Reserved

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**Auto tuning example**

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[[image:11_html_c64303b9c6a47ae9.png||class="img-thumbnail"]]

**✎Note:**

● When multiple instructions are used, the device number of (d) cannot be repeated.

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● During the execution of auto-tuning, the (s3) parameter space cannot be modified.

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● The instruction occupies 26 point devices from the device specified in (s3).

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● PID instruction can be used multiple times in the program and can be executed at the same time, but the variable area used in each PID instruction should not overlap; it can also be used in step instructions, jump instructions, timing interrupts, and subroutines, in this case When executing the PID instruction, the (s3)+9 cache unit must be cleared in advance.

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● The maximum error of the sampling time Ts is -(1 operation cycle +1ms) +(1 operation cycle). If the sampling time Ts ≤ 1 operation cycle of the programmable controller, the following PID operation error (4D86H) will occur, and the PID operation will be executed with TS = operation cycle. In this case, it is recommended to use constant scan mode or use PID instruction in timer interrupt.

**Error code**

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102

|**Error code**|**Content**

103

|4085H|When the device specified in the read application instructions (s1), (s2), (s3), (d) exceeds the range of the corresponding device.

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|4086H|When the device specified in the write application instruction (s3) and (d) exceeds the range of the corresponding device.

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|4D80H|The sampling time is out of range.[[image:11_html_ba06296a94a7278d.gif]]

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|4D81H|Input filter constant (,,[[image:11_html_b81ea5473531b171.gif]] ,,) is out of range (.,,[[image:11_html_f00d00cbbb545887.gif]] ,,)

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|4D82H|The maximum ascent rate ([[image:11_html_b83270b056cb8a08.gif]] ) is out of range.,,[[image:11_html_61c6eece10272380.gif]],,

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|4D83H|The proportional gain (Kp) is out of range.,,[[image:11_html_23f8e4bf2ee8d30.gif]],,

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|4D84H|The integral gain (Ki) is out of range.[[image:11_html_f3c81825ddb8fe86.gif]]

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|4D85H|The differential gain (Kd) is out of range.[[image:11_html_3da2409ae3fe18b8.gif]]

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|4D86H|The sampling time (Ts) is less than the operation cycle.,,[[image:11_html_70d03c16f47cdb8a.gif]],,

**Example**

See manual.

== {{id name="_Toc32463"/}}{{id name="_Toc21837"/}}{{id name="_Toc31152"/}}**CCPID/CCPID calculation** ==

**CCPID**

This instruction is used to perform PID control that changes the output value according to the amount of input change.

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-[CCPID (s1) (s2) (s3) (d)]

124

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**Content, range and data type**

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|(s1)|Device number for storing the target value (SV)|-32767 to 32767|Signed BIN 16 bit|ANY16

130

|(s2)|Device number for storing the measured value (PV)|-32767 to 32767|Signed BIN 16 bit|ANY16

131

|(s3)|Device number for storing parameters|1 to 32767|Signed BIN 16 bit|ANY16

132

|(d)|Device number for storing output value (MV)|-32767 to 32767|Signed BIN 16 bit|ANY16

**Device used**

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137

|(% rowspan="2" %)**Instruction**|(% rowspan="2" %)**Parameter**|(% colspan="3" %)**Devices**|(((

138

**Offset modification**

)))|(((

**Pulse extension**

)))

|**D**|**R**|**SD**|**[D]**|**XXP**

143

|(% rowspan="4" %)CCPID|Parameter 1|●|●|●| |

144

|Parameter 2|●|●|●| |

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|Parameter 3|●|●|●| |

146

|Parameter 4|●|●|●| |

**Features**

After setting target value (s1), measured value (s2), parameter (s3) to (s3) +12 and executing the program, the calculation result (MV) will be stored to the output according to the first sampling time (s3) in the parameter Value (d). For details, please refer to the user manual of "Wecon CC Series ccpid Function Description v1.4".

**✎Note:**

It can be executed multiple times at the same time (there is no limit to the number of loops), but please note that the device numbers (s3) and (d) used in the calculation cannot be repeated.

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The instruction occupies 52 points of devices starting from the device specified in (s3).

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During the execution of auto-tuning, the (s3) parameter space cannot be modified.

**Error code**

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163

|**Error code**|**Content**

164

|4085H|When the device specified in the read application instructions (s1), (s2), (s3), (d) exceeds the range of the corresponding device.

165

|4086H|When the device specified in the write application instruction (s3) and (d) exceeds the range of the corresponding device.

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|4D80H|The sampling time is out of range.[[image:11_html_e20ffef8be00c7de.gif||class="img-thumbnail"]]

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|4D81H|Input filter constant ([[image:11_html_89233377f23913d1.gif||class="img-thumbnail" height="19" width="24"]] ) is out of range (,,[[image:11_html_fc04053cc1766938.gif||class="img-thumbnail"]] ,,)

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|4D82H|The maximum ascent rate ([[image:11_html_b83270b056cb8a08.gif||class="img-thumbnail"]] ) is out of range.,,[[image:11_html_6ec55fb8a0806a8a.gif||class="img-thumbnail"]],,

169

|4D86H|The sampling time (Ts) is less than the operation cycle.,,[[image:11_html_5760e7f0e774413a.gif||class="img-thumbnail"]],,

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|4D87H|The proportional gain (Kp) is out of range.,,[[image:11_html_7ce2946bf919a62d.gif||class="img-thumbnail"]],,

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|4D88H|The integral time constant (Ti) is out of range.,,[[image:11_html_667c81877b8381e.gif||class="img-thumbnail"]],,

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|4D89H|The differential time constant (Td) is out of range.,,[[image:11_html_b1f11c46b396094.gif||class="img-thumbnail"]],,

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|4D90H|The upper limit of CCPID output is less than the lower limit.

**Example**

See "__CCPID Instruction Manual__".

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== **{{id name="_Toc8661"/}}{{id name="_Toc13227"/}}{{id name="_Toc18478"/}}{{id name="_Toc29418"/}}{{id name="_Toc5268"/}}{{id name="_Toc5168"/}}{{id name="_Toc307"/}}FPID/FPID calculation** ==

**FPID**

The function of this instruction is to adjust PID control parameters by fuzzy algorithm.

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-[FPID (s) (d1) (d2) (d3)]

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187

**Content, range and data type**

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|(s)|Store the start number of the device of the fuzzy parameter table (no input required)|-|Signed BIN 16 bit|ANY16

192

|(d1)|Start number of the device storing the initialization parameters|-|Signed BIN 16 bit|ANY16

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|(d2)|Store the start number of the device of the input PID parameter|-|Signed BIN 16 bit|ANY16

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|(d3)|The start number of the device that stores the adjusted PID parameters|-|Signed BIN 16 bit|ANY16

**Device used**

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**Pulse extension**

)))

|**D**|**R**|**SD**|**LC**|**[D]**|**XXP**

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|(% rowspan="4" %)FPID|Parameter 1|●|●|●|●| |

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|Parameter 2|●|●|●|●| |

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|Parameter 3|●|●|●|●| |

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|Parameter 4|●|●|●|●| |

**Features**

This instruction needs to be used in conjunction with the PID instruction. It completes the fuzzy calculation of the adjustments of the three parameters of PID, Kp, Ki, and Kd. By passing in the three parameters of the PID, the new three parameters are calculated and substituted into the PID for output control.

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**Parameter Description:**

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|(% colspan="6" %)**S parameter setting**

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|Parameter 1|S|-|-|-|-

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220

|(% colspan="6" %)**d1 parameter setting**

|d1+1

|d1+3

|d1+5

|d1+7

|d1+9

|d1+11

|d1+13

|d1+15

|d1+17

|d1+19

|︙|︙|︙|︙|Reserved|-

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252

|(% colspan="6" %)**d2 parameter setting**

|Parameter 4|d2+3|Kp|16-bit integer|PID initial Kp value|-

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|Parameter 5|d2+4|KI|16-bit integer|PID initial Ki value|-

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|Parameter 6|d2+5|KD|16-bit integer|PID initial Kd value|-

|d2+9

|(% colspan="6" %)**d3 parameter setting**

|Parameter 4|d3+3|Kp|16-bit integer|Kp value of PID after adjustment|-

272

|Parameter 5|d3+4|KI|16-bit integer|Ki value of PID after adjustment|-

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|Parameter 6|d3+5|KD|16-bit integer|Kd value of PID after adjustment|-

**✎Note:**

The instruction starts from the device specified in (d1) and occupies 38 points of the device, and initializes the parameters. Normally, it only needs to be initialized once before calling (some parameters are fixed) (occupies 38 words space).

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The instruction starts with the device specified in (d2) and occupies 12 points of the device, input parameters, and input the first 6 parameters, where Kp, Ki, Kd are the initial values of the PID control parameters (occupies 12 words space) .

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The instruction starts from the device specified in (d3) and occupies 8 points of soft elements and output parameters, among which Kp, Ki, Kd are the parameter values after fuzzy adaptive calculation, which can be input to the designated position of PID (occupy 8 words space).

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The FPID instruction occupies 58 words. The address of each operand must have a specified interval interval, which cannot be occupied by other instructions.

**Error code**

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290

|**Error code**|**Content**

291

|4085H|When the device specified in the read application instructions (d1), (d2), (d3) exceeds the range of the corresponding device.

292

|4086H|When the device specified in the write application instructions (d1), (d2), (d3) exceeds the range of the corresponding device.

293

|4D91H|FPID calculation cycle is less than or equal to 0

294

|4D92H|FPID parameter range error

295

|4D93H|FPID initial flag error

**Example**

~1. Parameter d1

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[[image:11_html_93e9f66475d6eb0c.png||class="img-thumbnail"]]

2. Parameter d2

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[[image:11_html_548b859bc5568099.png||class="img-thumbnail"]]

3. Invoke FPID

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[[image:11_html_599ccfa817c379fd.png||class="img-thumbnail"]]

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== **{{id name="_Toc30590"/}}{{id name="_Toc20656"/}}{{id name="_Toc13618"/}}PRUN/8 digit transmission (16-bit data)** ==

**PRUN(P)**

After processing the device numbers of (s) and (d) with designated digits as octal numbers, transfer the data.

-[PRUN (s) (d)]

**Content, range and data type**

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|(s)|Digit designation*1|-|BIN16 bit|ANY16

327

|(d)|Transfer destination device number*1|-|BIN16 bit|ANY16

**Device used**

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332

|(% rowspan="2" %)**Instruction**|(% rowspan="2" %)**Parameter**|(% colspan="3" %)**Devices**|(((

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**Offset modification**

)))|(((

**Pulse extension**

)))

|**KnX**|**KnY**|**KnM**|**[D]**|**XXP**

338

|(% rowspan="2" %)PRUN|Parameter 1|●| |●|●|●

339

|Parameter 2| |●|●|●|●

**Features**

• 8-digit device → decimal device

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[[image:11_html_3c0c842b3d3c7a4.png||class="img-thumbnail"]]

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• Decimal digit device → octal digit device

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[[image:11_html_437032b41f24ad69.png||class="img-thumbnail"]]

**Error code**

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356

|**Error code**|**Content**

357

|4085H|When reading the specified device range exceeds the corresponding device range

358

|4086H|When the specified device range for writing exceeds the range of the corresponding device

**Example**

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[[image:11_html_e5ea991cf7b84dc0.png||class="img-thumbnail"]]

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As shown in the above Circuit program:

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X0 to X17 take the value of octal digits and pass it to the Devices corresponding to M.

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[[image:11_html_4d9c97b634dc29b1.png||class="img-thumbnail"]]

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== **{{id name="_Toc18093"/}}{{id name="_Toc173"/}}{{id name="_Toc26928"/}}TRH/Conversion of wet and dry bulb temperature and humidity** ==

**TRH**

This instruction completes the conversion of dry bulb temperature, wet bulb temperature and corresponding humidity.

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-[TRH (d1) (s) (d2) (N)]

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**Content, range and data type**

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|(N)|mode|0 to 1|Signed BIN 32 bit|ANY32

**Device used**

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392

|(% rowspan="2" %)**Instruction**|(% rowspan="2" %)**Parameter**|(% colspan="11" %)**Devices**|(((

**Offset**

**modification**

)))|(((

**Pulse**

**extension**

)))

|**KnX**|**KnY**|**KnM**|**KnS**|**T**|**C**|**D**|**R**|**SD**|**K**|**H**|**[D]**|**XXP**

402

|(% rowspan="4" %)TRH|Parameter 1| | | | |●|●|●|●|●| | |●|

403

|Parameter 2| | | | |●|●|●|●|●| | |●|

404

|Parameter 3| | | | |●|●|●|●|●| | |●|

405

|Parameter 4|●|●|●|●|●|●|●|●|●|●|●|●|

**Features**

（N）There are two modes to choose from:

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Mode 0: Calculate the corresponding humidity by wet bulb temperature and dry bulb temperature.

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Mode 1: Calculate the corresponding wet bulb temperature by dry bulb temperature and humidity.

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The conversion process formula is as follows:

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Assuming that the wet bulb temperature is A, the dry bulb temperature is B, and the corresponding current humidity is C, the three meet the following conditions:

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[[image:11_html_f9763504e639b084.gif||class="img-thumbnail"]]

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(% style="text-align:center" %)

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[[image:11_html_9eb43b8fba5e28f3.gif||class="img-thumbnail"]]

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[[image:11_html_f8a8e1f6b18e6e61.gif||class="img-thumbnail"]]

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(% style="text-align:center" %)

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[[image:11_html_c128b23414b3cae9.gif||class="img-thumbnail"]]

**✎Note:**

● The wet bulb temperature is not greater than the dry bulb temperature. When the two are the same, the humidity reaches the maximum 100%.

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● The unit of dry and wet bulb temperature is (℃).

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● The general value range of dry bulb is between 0 to 100℃, the command does not judge its range, so pay special attention when using this command.

**Error code**

(% class="table-bordered" %)

442

|**Error code**|**Content**

443

|(% rowspan="4" %)4084H|The value specified in (N) is out of the following range. 0 to 1

444

|The value specified in (d1) is out of the following range. 0 to 100

445

|A negative value is specified in (s).

446

|A negative value is specified in (d2).

447

|4085H|The output result of (d1)(s)(d2)(N) in the read application instruction exceeds the device range

448

|4086H|The output result of (d1)(d2) in the writing application instruction exceeds the device range

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450

Dry and wet bulb humidity comparison table

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[[image:11_html_6cf6e76e6b1a3e12.png||class="img-thumbnail"]]

**Example**

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[[image:11_html_4acab72ee19939e5.png||class="img-thumbnail"]]

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== **CCPID instruction introduction manual** ==

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**Background and purpose**

(1) Background:

PID (proportion, integral, derivative) controller has been the earliest practical controller for nearly a hundred years, and it is still the most widely used industrial controller. The PID controller is simple and easy to understand, and does not require precise system models and other prerequisites in use, making it the most widely used controller.

(2) Purpose:

You might not be familiar with the parameter settings in the new series of CCPID for the first time, this manual could let you quickly understand the meaning of each parameter in the CCPID and the influence on the control effect, so that you can quickly learn the CCPID.

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**Description of the host CCPID instruction**

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**Instruction description**

475

476

**Content, range and data type**

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478

(% class="table-bordered" %)

479

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|CCPID|PID Operation|16|No|CCPID [[image:11_html_253eb1176b58e989.png]] [[image:11_html_80fccb1046bf8776.png]] [[image:11_html_8760537828f7beaf.png]] [[image:11_html_8b4fbd61f8ea9808.png]]|9

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(% class="table-bordered" %)

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|**D**|**R**|**SD**|**[D]**|**XXP**

485

|(% rowspan="4" %)CCPID|Parameter 1|●|●|●| |

486

|Parameter 2|●|●|●| |

487

|Parameter 3|●|●|●| |

488

|Parameter 4|●|●|●| |

**Device used**

[[image:11_html_954290ac172c672b.jpg||class="img-thumbnail"]] is the target value (SV) of PID control;

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[[image:11_html_31f47ac5eec30067.jpg||class="img-thumbnail"]] is the measured feedback value (PV);

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496

[[image:11_html_6dcdd8fc88703a47.jpg||class="img-thumbnail"]] is the start address of the buffer area for setting parameters required for PID operation and saving intermediate results, occupying a total of 52 variable units of subsequent addresses (recommended to reserve 100 continuous spaces).The value range is D0 to D7,948, it is better to specify power failure retention, and the setting value remains after power supply is off. Otherwise,the buffer needs to be assigned value before starting the calculation for the first time. The function and parameter description of each unit are described in this section;

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498

[[image:11_html_7e06d96423d5de52.jpg||class="img-thumbnail"]] is the storage unit (MV) of the PID calculation result. Please specify it as a non-battery retentive area, otherwise it needs to be initialized and cleared before the first start of calculation.

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500

(% style="text-align:center" %)

501

[[image:11_html_8eeef07485b91193.jpg||class="img-thumbnail"]]

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503

**Programming example**

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505

The parameter description is as follows:

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507

In D9, the target value of PID adjustment is stored, and D10 is the closed-loop feedback value. Note that D9 and D10 must be of the same dimension, such as both 0.01MPa units, or 1℃ units, etc.;

508

509

A total of 52 units of D200 to D224 are used to store the set value and process value of PID operation. These values must be set item by item before the first PID calculation;

510

511

D130 unit is used to store the calculated control output value to control the execution of the action.

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513

The functions and setting methods of the parameter values of each unit used by [[image:11_html_6dcdd8fc88703a47.jpg||class="img-thumbnail"]] are described in the following table:

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[[image:11_html_6dcdd8fc88703a47.jpg||class="img-thumbnail"]] to [[image:11_html_6dcdd8fc88703a47.jpg||class="img-thumbnail"]] +14 is the parameter range that can be set (parameters set when CCPID is executed).

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517

[[image:11_html_6dcdd8fc88703a47.jpg||class="img-thumbnail"]] +15 to [[image:11_html_6dcdd8fc88703a47.jpg||class="img-thumbnail"]] +21 is the space used internally by CCPID control.

518

519

[[image:11_html_6dcdd8fc88703a47.jpg||class="img-thumbnail"]] +22 to [[image:11_html_6dcdd8fc88703a47.jpg||class="img-thumbnail"]] +51 is the parameter space used in the auto-tuning process.

520

521

(% class="table-bordered" %)

522

|**Unit**|**Features**|**Setting instructions**|**Supplement**

523

| |Sample time (TS)|The set range is 1 to 32,767 (ms), but greater than PLC program scan cycle.|It is how often the instruction calculates and updates the output value (MV). When TS is less than one scan time, PID instruction is executed with one scan time and alarm 4D86H. When TS ≤ 0, alarm 4D80H and no execution.

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|+1|Action direction (ACT)|(((

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bit0: 0=positive action; 1=reverse action bit2: auto-tuning transition zone switch. 0=not open;1=open

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bit3: 0=unidirection; 1=bidirection

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Bit4: 0=auto-tuning does not execute; 1=execute auto-tuning

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[Bit6:0=Two-stage auto-tuning does not execute. 1=Execute two-stage auto-tuning (bit4 must be set to 1).

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bit7: 0=Three-stage auto-tuning does not execute. 1=Execute three-stage auto-tuning (bit4 must be set to 1 )]

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The Others cannot be used.

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)))|(((

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bit0: Positive action: similar heating system, when the temperature is lower than the set value, increases the output ; Reverse action: similar cooling system, when the temperature is greater than the set value, increases the output.

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bit2: Self-tuning transition zone switch. There is a transition zone size of 1.5℃ when opened.

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bit3: Bidirection indicates that outputs the positive and negative values to the heating system or the cooling system to control two external systems by one PID.

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bit4: **✎**When bit4=1 and bit6 and bit7 are not 1, auto-tuning is not executed. **✎**When bit4=0 and one of bit6 and bit7 is 1, auto-tuning is not executed. **✎**When bit4=1 and bit6 and bit7 are both 1, auto-tuning is executed

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)))

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|+2|Filter coefficient|The first-order inertia filter of feedback amount (0 to 100%) has a range of 0 to100|When the value is greater than or equal to 100, it will be executed as 0, that is, no filtering will be executed;

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|+3|Proportional gain(Kp)|Set range: 0 to 30,000[%]|Overrun error 4D87H

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|+4|Integration time (Ti)|Ti is integration time, and the range is 0 to 3,600 (s)|Overrun error 4D88H

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|+5|Differential time (Td)|Td is derivative time, and the range is 0 to 1,000 (s)|Overrun error 4D89H

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|+6|Working interval|Operating temperature setting enabled by PID (0 indicates no effect) The range is 0 to 1,000|It is recommended to be greater than 5°C, that is, 50 (precision 0.1°C). If it exceeds the range, the boundary value will be taken.

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|+7|Output low limit|(((

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Range: -10,000 to 10,000.

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Recommended setting range: -2,000 or 0 (when S3+1 bit3=0, the lower limit = 0;

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when bit3=1, the lower limit = -2,000)

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)))|(((

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~1. Self-tuning initialization:

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① Unidirection control: the lower limit is 0;

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② Bidirection control: If the lower limit is greater than 0, adjust the lower limit to 0; if the upper limit and the lower limit are equal to 0, the default lower limit is -2,000. **✎**Note: If set to -2,000, and the output value (MV) is less than -2,000, it will output -2,000.

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2. During the control process, the lower limit is dynamically adjustable. If the lower limit is greater than or equal to the upper limit, error 4D90H will be reported.

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)))

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|+8|Output upper limit|(((

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Value range: -10,000 to 10,000.

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Recommended setting value is 2,000

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)))|(((

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~1. Self-tuning initialization:

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① Unidirection control: If the upper limit is less than 0, the default upper limit is 2,000;

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② Bidirection control: If the upper limit is less than 0, adjust the upper limit to 0; if the upper limit and the lower limit are equal to 0, the default upper limit is -2,000. **✎**Note: If set to -2,000 and the output value (MV) is greater than -2,000, it will output 2,000.

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2. During the control process, the upper limit is dynamically adjustable. If the lower limit is greater than or equal to the upper limit, error 4D90H will be reported.

)))

|+9|Mode setting|(((

0: Overshoot allowed

1: Slight overshoot or no overshoot

2: Dynamic setting

)))|(((

0:Overshoot allowed (ukd = 100)

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1: Slight overshoot or no overshoot mode (ukd = 300)

)))

|+10|(((

Scale factor

(ukp)

)))|Typically sets value to 100 (default 100) [enabled when S3+9 is set to 2].The range is 1 to 500.|When the value is less than or equal to 0, or greater than 500, the boundary value will be taken.

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|+11|Integral coefficient (uki)|Typically sets value to 50 (default 50) [enabled when S3+9 is set to 2]. The range is 1 to 300.|When the value is less than or equal to 0, or greater than 300, the boundary value will be taken.

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|+12|Differential coefficient (ukd)|Typically sets value to 50 (default 100. 300 to 400 can be set when slight overshoot is required) [Enable when S3+9 is set to 2]. The range is 1 to 500.|When the value is less than or equal to 0, or greater than 500, the boundary value will be taken.

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|+13|Maximum ascent rate (DeltaT)|The range is 0 to 32,000, which is the threshold of integral increment|Overrun error 4D82H

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|+14|Filtering (C0)|The range is 0 to 1,023, integral part filtering|Overrun error 4D81H

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|+15|(% rowspan="3" %)reserved for internal control|(% rowspan="3" %)Internal control space occupation|(% rowspan="3" %)

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|┆

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|+21

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|+22|(% rowspan="3" %)used space for self-tuning|(% rowspan="3" %)New self-tuning space for internal use|(% rowspan="3" %)

|┆

|+51

1) The auto-tuning process occupies the space of S3+22 to S3+51. When the auto-tuning is successful, the adjusted parameters will be written into the space of S3+2 to S3+21.

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2) +2 filter coefficient α: Processing in first-order inertial filter

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Formula: **T,,now,,=(100-α)×T,,α,,+α×T,,old,,**

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T,,α ,,is the currently measured temperature. T,,old ,,is the temperature that participated in the PID calculation last time. T,,now ,,is the temperature used for the current PID calculation. α is the filter coefficient (when α=0, no filtering is performed, and the range of α is 0 to 100.(If there is a temperature with a small overshoot but a long stabilization time, the parameter can be set to 80, and analyze the specific problems in detail)

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3) +6 work range: Twork(example: 170 represents 17℃)

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(% style="text-align:center" %)

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[[image:11_html_7ab814bb49fffa5a.gif||class="img-thumbnail"]]

4) +9 working mode:

0: Working mode that allows overshoot

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1: Slight overshoot or no overshoot working mode

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2: Custom settings; to achieve by setting +10, +11, +12 three coefficients.

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5) +1 bit2 self-tuning transition zone switch: (upper limit 1℃, low limit 0.5℃)

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The transition zone description in forward control:

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(% style="text-align:center" %)

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[[image:11_html_d90c24627566bf2f.gif||class="img-thumbnail"]]

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In the heating process, when PV≤SV+1℃, 100% power output; when PV＞SV+1℃, no output.

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In the cooling process, when PV＜SV-0.5℃, 100% power output; When PV≥SV-0.5℃, no output.

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The transition zone description in reverse control:

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(% style="text-align:center" %)

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[[image:11_html_d3c25044a54c62ce.gif||class="img-thumbnail"]]

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In the cooling process, when PV≥SV-1℃, 100% power output; when PV＜SV-1℃, no output.

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In the heating process, when PV＞SV+0.5℃, 100% power output; When PV≤SV+0.5℃, no output.

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The transition zone description in bidirectional control:

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(% style="text-align:center" %)

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[[image:11_html_9eb35607c95b1580.gif||class="img-thumbnail"]]

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In the heating process, when PV≤SV+1℃, 100% power heating output; when PV>SV+1℃, 100% power cooling output.

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In the cooling process, when PV＜SV-0.5℃, 100% power heating output. When PV≥SV-0.5℃, 100% power cooling output

**Programming case**

**CCPID application configuration**

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(1) Parameter setting

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(% style="text-align:center" %)

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[[image:11_html_36a152ee534a7f24.png||class="img-thumbnail"]]

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(2) CCPID control process setting

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(% style="text-align:center" %)

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[[image:11_html_51d50fa8b154baca.png||class="img-thumbnail"]]

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(% style="text-align:center" %)

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[[image:11_html_66c8a636f6176c1f.png||class="img-thumbnail"]]

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(3) Bidirection control

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(% style="text-align:center" %)

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[[image:11_html_234093eac2fe184d.png||class="img-thumbnail"]]

**✎Note:**

~1. CCPID is a special instruction for operation control. CCPID operation will be executed only after the sample time is reached.

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2. There is no limit to the number of times the CCPID instruction can be used, but+51 cannot be repeated.

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3. Before CCPID instruction is executed, CCPID parameters need to be set.

**Case analysis**

**(1) Control requirements**

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The control environment of this example is a kettle. The configuration is controlled by PLC-5V2416 host with 4PT module, and PI8070 screen is used for data storage and process curve viewing.

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**(2) Sample program**

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(% style="text-align:center" %)

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[[image:11_html_f0a22955a8da7129.png||class="img-thumbnail"]]

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(% style="text-align:center" %)

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[[image:11_html_ad08c65bd672c66e.png||class="img-thumbnail"]]

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**(3) Parameter description**

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(% class="table-bordered" %)

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|**PLC device**|**Control instructions**

703

|M0|Set auto tuning

704

|M1|CCPID instruction calculation start

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|M2|CCPID operating status

706

|Y0|Pulse output with adjustable pulse width

707

|D0|Temperature measured value

708

|D1|Temperature setting value

709

|D100|sample time

710

|D101|Control detail settings

711

|D102|First-order inertial filter coefficient

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|D106|Working interval

713

|D109|Operating mode

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**(4) Parameter control effect description**

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1) Boiling water experiment

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① Auto-tuning process and control process (no transition zone setting), take two-stage auto-tuning as an example

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(% style="text-align:center" %)

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[[image:11_html_9149b1e837158a17.gif||class="img-thumbnail"]]

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Figure 1 Auto-tuning process curve without transition zone

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When the control system is a single temperature control system or a system where environmental interference does not cause large fluctuations. Generally the automatic tuning without transition zone is selected, so that the self-tuning process can be completed more quickly than the method with transition zone.

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②Self-tuning process and control process (transition zone setting)

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(% style="text-align:center" %)

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[[image:11_html_a1e8ad7a31bb04af.gif||class="img-thumbnail"]]

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Figure 2 Self-tuning process curve with transition zone

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It is more suitable in a two-way control system with transition zone self-tuning process. The transition zone has a range of 1.5°C. The upper limit is 1°C, and the lower limit is 0.5°C.

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2) Difference in working interval setting

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(% style="text-align:center" %)

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[[image:11_html_4140432ce11883ad.gif||class="img-thumbnail"]]

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Figure 3 Process curve under different working interval parameters

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(% style="text-align:center" %)

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[[image:11_html_f742d80c8cc95f35.gif||class="img-thumbnail"]]

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Figure 4 Process curve without different working interval parameters (heating process diagram)

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It can be seen from the partially enlarged graph that the parameters of the working interval have a certain influence on the overshoot and the stable time. In the case of allowing overshoot, setting the working interval parameters can make the overshoot smaller. This is because the deviation E of PID starting to work is relatively small, and the integration accumulation will not quickly saturate.

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3) Result of filter coefficient setting

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(% style="text-align:center" %)

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[[image:11_html_815ec6c129ae3891.gif||class="img-thumbnail"]]

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Figure 5 Process curve under different filtering parameters

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The figure above is the experimental result under the small overshoot coefficient, the sample time is 1s. The coefficients of the first-order inertial filtering are (20, 50, 70, 80, 90). After adding the inertia coefficient, the stability time of system control is greatly accelerated, and it is increased by about 6 minutes for the boiling water experiment. The overshoot is about 1.2°C to 1.7°C.

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Therefore, the introduction of first-order inertial filtering could greatly improve the PID environment where the temperature fluctuates to a certain extent and increase stabilization time.

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**✎Note: **This parameter of filter coefficient is helpful for systems with not very large hysteresis or the control effect of the phenomenon that the control amount fluctuates back and forth has been greatly improved.

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4) The difference in mode selection

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0: Overshoot allowed(ukd = 100)

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1: Small overshoot or no overshoot (ukd = 300)

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(% style="text-align:center" %)

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[[image:11_html_3a7b42c8f4672ce4.gif||class="img-thumbnail"]]

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Figure 6 Process curves in different working modes

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When selecting mode 1 (small overshoot or no overshoot), the stable temperature may be slightly higher than the set temperature (fluctuates above the set temperature).

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5) The function of the coefficient

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(% style="text-align:center" %)

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[[image:11_html_74a7527eace55103.gif||class="img-thumbnail"]]

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Figure 7 Process curve under dynamic setting

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When selecting working mode 2, there are three corresponding adjustable parameters: ukp[S3+10], uki[S3+11], ukd[S3+12]. Usually, the default parameters can be used for ukp and uki. Adjust the value of ukd could achieve the control effect.

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786

Ukp is adjusted when the value of Kp reaches the maximum value, and the default value is usually 100.

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788

Uki is adjusted when periodic oscillations occur. Gradually increase the value of uki to track the control effect.

Wiki source code of 11 Special instructions

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