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Wiki source code of LX3V-4TC

Last modified by Stone Wu on 2022/09/14 08:35
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Leo Wei 1.1 1 = **1 Introduction** =
2
3 The LX3V-4TC expansion module amplifies the signal from four thermocouple sensors (Type K or J) and converts the data into 12 bit reading’s stored in the main unit. Both Centigrade (°C) and Fahrenheit (°F) can be read.
4
5 Reading resolution is 0.2°C/0.72°F of Type K and 0.3°C/0.54°F of Type J.
6
7 All data transfers and parameter settings are adjusted via software control of the LX3V-4TC; by use of the TO/FROM applied instructions in the PLC.
8
9 LX3V-4TC consumes 5V voltage from LX3V main unit or active extension unit, 90mA current of power supply. Thermocouples with the following specifications can be used: Type K, Type J.
10
11 = **2 External dimensions** =
12
13 (% style="text-align:center" %)
Stone Wu 3.1 14 [[image:LX3V-4TC_html_b228e95b12be2343.png||height="403" width="1000" class="img-thumbnail"]]
Leo Wei 1.1 15
Stone Wu 3.1 16 1. Extension cable and connector
17 1. Com LED: Light when communicating
18 1. Power LED: Light when connect to 24V
19 1. State LED: Light when normal condition
20 1. Module name
21 1. Analog signal output terminal
22 1. Extension module interface
23 1. DIN rail mounting slot
24 1. DIN rail hook
25 1. Mounting holes (φ4.5)
Leo Wei 1.1 26
27 **Using crimp terminations**
28
29 (((
30 * Be sure to use the crimp-style terminals that satisfy the dimensional requirements shows in the left figure.
31 * Apply 0.5 to 0.8 N.m (5 to 8 kgf.cm) torque to tighten the terminals to prevent abnormal operation.
32
33 (% style="text-align:center" %)
Stone Wu 3.1 34 [[image:LX3V-4TC_html_67891e8f02a25438.png||height="199" width="300" class="img-thumbnail"]]
Leo Wei 1.1 35 )))
36
37 = **3 Terminal Layouts** =
38
39 (% style="text-align:center" %)
Stone Wu 3.1 40 [[image:LX3V-4TC_html_784767a15ebff85b.png||height="465" width="500" class="img-thumbnail"]]
Leo Wei 1.1 41
42 (((
Stone Wu 3.1 43 The compensating cables that can be used for connecting with the thermocouple are the following.
Leo Wei 1.1 44
Stone Wu 3.1 45 * Type K: KX-G, KX-GS, KX-H, KX-HS, WX-G, WX-H, VX-G
46 * Type J: JX-G, JX-H
Leo Wei 1.1 47
48 For every 10Ω of line resistance, the compensating cable will indicate a temperature 0.12°C higher than actual.
49
50 Check the line resistance before using.
51
52 Long compensating cables are more prone to noise interference, therefore a short (less than 100m) compensating cable is recommended.
53 )))
54
55 Unused channels should have a wire link connected between the + and – terminals to prevent an errors being detected on that channel.
56
57 * If there is excessive electrical noise, connect the FG terminal to the ground terminal on the unit.
58 * Connect the ground terminals of the LX3V-4TC module and the PLC. Use grounding on the PLC.
59 * The 24V DC built-in supply of the PLC may be used as the power supply.
60
61 = **4 Installation notes and usage** =
62
63 **Environmental specification**
64
65 (% class="table-bordered" %)
Stone Wu 3.1 66 |=**Item**|=**Specification**
Leo Wei 1.1 67 |Environmental specifications (excluding following)|Same as those for the LX3V base unit
68 |Dielectric withstand voltage|500V AC, 1min (between all terminals and ground)
69
70 **Power supply specification**
71
72 (% class="table-bordered" %)
Stone Wu 3.1 73 |=(% scope="row" %)**Item**|=**Description**
74 |=Analog circuits|±24V DC±10%,55mA
75 |=Digital circuits|24V DC,35mA(internal power supply from base unit)
Leo Wei 1.1 76
77 **Performance specification**
78
79 (% class="table-bordered" %)
80 |(% rowspan="2" %)**Item**|(% colspan="2" %)**Centigrade**|(% colspan="2" %)**Fahrenheit**
81 |(% colspan="4" %)**Both °C and °F readings are available by reading the appropriate buffer memory area.**
82 |**Analog input signal**|(% colspan="4" %)Thermocouple: Type K or J (either can be used for each channel), 4 channels.
83 |(% rowspan="2" %)**Rated temperature range**|Type K|-100°C to 1200°C|Type K|-148°F to +2192°F
84 |Type J|-100°C to 600°C|Type J|-148°F to +1112°F
85 |(% rowspan="3" %)**Digital output**|Type K|-1000 to 12000|Type K|-1480 to 21920
86 |Type J|-1000 to 6000|Type J|-1480 to 11120
87 |(% colspan="4" %)12-bit conversion ,save as complement of 2 in 16 bits
88 |(% rowspan="2" %)**Resolution**|Type K|0.4°C|Type K|0.72°F
89 |Type J|0.3°C|Type J|0.54°F
90 |**Overall accuracy**|(% colspan="4" %)(((
91 ±5% full scale + 1°C
92
93 Freezing point of pure water 0°C / 32°F
94 )))
95 |**Conversion speed**|(% colspan="4" %)(240ms ± 2%) × 4 channels (unused channels are not converted)
96
Stone Wu 3.1 97 (% class="box infomessage" %)
98 (((
Leo Wei 1.1 99 **Note:** Earth-tipped thermocouples are not suitable for use with this module.
Stone Wu 3.1 100 )))
Leo Wei 1.1 101
102 **Analog input**
103
104 (% class="table-bordered" %)
Stone Wu 3.1 105 |=(% scope="row" %)**Feature Conversion**|[[image:LX3V-4TC_html_c007c8dafe24466b.gif||class="img-thumbnail"]]|[[image:LX3V-4TC_html_c9d8982ef2fe950b.gif||class="img-thumbnail"]]
Leo Wei 1.1 106
107 **Miscellaneous**
108
109 (% class="table-bordered" %)
Stone Wu 3.1 110 |=(% scope="row" %)**Item**|=**Description**
111 |=Isolation|(((
Leo Wei 1.1 112 Photo-coupler isolation between analog and digital circuits. DC/DC converter isolation of power from LX3V MPU.
113
114 No isolation between analog channels.
115 )))
Stone Wu 3.1 116 |=Total points|(((
Leo Wei 1.1 117 8 points taken from the LX3V expansion bus
118
119 (can be either inputs or outputs)
120 )))
121
122 **Buffer memory**
123
124 (% class="table-bordered" %)
Stone Wu 3.1 125 |=(% scope="row" style="width: 216px;" %)**BFM**|=(% style="width: 859px;" %)**Description**
126 |=(% style="width: 216px;" %)*#0|(% style="width:859px" %)Thermocouple Type K or J selection mode. At shipment: H0000
127 |=(% style="width: 216px;" %)*#1→ #4|(% style="width:859px" %)CH1 to CH4 Averaged temperature reading to be averaged (1 to 4,096) Default = 8
128 |=(% style="width: 216px;" %)*#5→ #8|(% style="width:859px" %)CH1 to CH4 Averaged temperature in 0.1°C units
129 |=(% style="width: 216px;" %)*#9→ #12|(% style="width:859px" %)CH1 to CH4 Present temperature in 0.1°C units
130 |=(% style="width: 216px;" %)*#13→ #16|(% style="width:859px" %)CH1 to CH4 Averaged temperature in 0.1°F units
131 |=(% style="width: 216px;" %)*#17→ #20|(% style="width:859px" %)CH1 to CH4 Present temperature in 0.1°F units
132 |=(% style="width: 216px;" %)*#21→ #27|(% style="width:859px" %)Reserved
133 |=(% style="width: 216px;" %)*#28|(% style="width:859px" %)Digital range error latch
134 |=(% style="width: 216px;" %)#29|(% style="width:859px" %)Error status
135 |=(% style="width: 216px;" %)#30|(% style="width:859px" %)Identification code K2030
136 |=(% style="width: 216px;" %)#31|(% style="width:859px" %)Software version
Leo Wei 1.1 137
138 1. The LX3V-4TC module communicates with the PLC via buffer memories.
139 1. BFMs #21 to #27 and #31 are reserved. All non-reserved BFMs can be read by the PLC using the FROM instruction.
140 1. BFMs (buffer memories) marked with an “*” can be written to, the special function block using the TO instruction.
141
Stone Wu 3.1 142 **Buffer Memory BFM #0: Thermocouple Type K or J selection mode**
Leo Wei 1.1 143
144 BFM #0 is used to select Type K or J thermocouples for each channel. Each digit of a 4 digit hexadecimal number corresponds to one channel, the least significant digit being channel 1.
145
146 **Example**
147
Stone Wu 3.1 148 * 0= Type K
149 * 1= Type J
150 * 3= Not used
Leo Wei 1.1 151
152 (% style="text-align:center" %)
Stone Wu 3.1 153 [[image:LX3V-4TC_html_76092feedff738c5.png||height="236" width="400" class="img-thumbnail"]]
Leo Wei 1.1 154
155 * A/D conversion time is 240ms per channel. When “3" (unused) is set for a channel, A/D conversion is not executed for that channel, therefore, the total conversion time is decreased. In the above example, the conversion time is as follows:
156
157 __240ms (conversion time per channel) × 2channels (number of channels used) = 480ms (total conversion time)__
158
Stone Wu 3.1 159 **Buffer Memory BFMs #1 to #4: Number of temperature readings to be averaged**
Leo Wei 1.1 160
161 When the number of temperature readings to be averaged is specified for BFMs #1 to #4, the averaged data is stored in BFMs #5 to #8 (°C) and #13 to #16 (°F). Only the range 1 to 256 is valid for the number of temperature readings to be averaged. If a value outside of this range is entered, a default value of 8 is used.
162
Stone Wu 3.1 163 **Buffer Memory BFMs #9 to #12 and #17 to #20: Present temperature**
Leo Wei 1.1 164
165 These BFMs store the present value of the input data. This value is stored in units of 0.1°C or 0.1°F, but the resolution is only 0.4°C or 0.72°F for Type K and 0.3°C or 0.54°F for Type J.
166
167 **States information**
168
Stone Wu 3.1 169 **Buffer memory BFM#28: Digital range error latch**
Leo Wei 1.1 170
171 BFM #29 b10 (digital range error) is used to judge whether the measured temperature is within the unit’s range or not.
172
173 BFM #28 latches the error status of each channel and can be used to check for thermocouple disconnection.
174
175 (% class="table-bordered" %)
176 |**b15 or b8**|**b7**|**b6**|**b5**|**b4**|**b3**|**b2**|**b1**|**b0**
177 |(% rowspan="2" %)Not used|High|Low|High|Low|High|Low|High|Low
178 |(% colspan="2" %)CH4|(% colspan="2" %)CH3|(% colspan="2" %)CH2|(% colspan="2" %)CH1
179
Stone Wu 3.1 180 * **Low:** Latches ON when temperature measurement data goes below the lowest temperature measurement limit.
181 * **High: **Turns ON when temperature measurement data goes above the highest temperature measurement limit, or when a thermocouple is disconnected.
Leo Wei 1.1 182
183 When an error occur the temperature data before the error is latched. If the measured value returns to within valid limits the temperature data returns to normal operation. (Note: The error remains latched in (BFM #28))
184
185 An error can be cleared by writing K0 to BFM #28 using the TO instruction or turning off the power.
186
Stone Wu 3.1 187 **Buffer memory BFM#29: Error states**
Leo Wei 1.1 188
189 (% class="table-bordered" %)
Stone Wu 3.1 190 |=(% scope="row" style="width: 210px;" %)**BFM#29 Bit device**|=(% style="width: 578px;" %)**ON**|=**OFF**
191 |=(% style="width: 210px;" %)b0: Error|(% style="width:578px" %)When any of b1 to b3 is ON A/D conversation is stopped for the error channel|No error
192 |=(% style="width: 210px;" %)b1: Reserved|(% style="width:578px" %)Reserved|Reserved
193 |=(% style="width: 210px;" %)b2: Power source|(% style="width:578px" %)24V DC power supply failure|Power supply normal
194 |=(% style="width: 210px;" %)b3: Hardware error|(% style="width:578px" %)A/D converter or other hardware failure|Hardware normal
195 |=(% style="width: 210px;" %)b4 to b9: Reserved|(% style="width:578px" %)Reserved|Reserved
196 |=(% style="width: 210px;" %)b10: Digital range error|(% style="width:578px" %)Digital output/analog input value is outside the specified range.|Digital output value is normal
197 |=(% style="width: 210px;" %)b11: Averaging error|(% style="width:578px" %)Selected number of averaged results is outside the available range. See BFM#1 to #4|Averaging is normal (between 1 to 256)
198 |=(% style="width: 210px;" %)b12 to b15: Reserved|(% style="width:578px" %)Reserved|Reserved
Leo Wei 1.1 199
Stone Wu 3.1 200 **Identification Code Buffer Memory BFM #30**
Leo Wei 1.1 201
202 The identification code or ID number for module is read from buffer memory BFM #30 using the FROM command.
203
204 This number for the LX3V-4TC unit is K2030.
205
206 The PLC can use this facility in its program to identify the expansion module before commencing data transfer from and to the expansion module.
207
Stone Wu 3.1 208 **System block diagram**
Leo Wei 1.1 209
210 (% style="text-align:center" %)
Stone Wu 3.1 211 [[image:LX3V-4TC_html_16d7fd78e3b1d23f.png||height="322" width="600" class="img-thumbnail"]]
Leo Wei 1.1 212
213 = **5 Example** =
214
215 In the program shown below, the LX3V-4TC occupies the position of special block number 2 (that is the third closest block to the PLC). A Type K thermocouple is used on CH1 and a Type J on CH2. CH3 and CH4 are not used. The averaging count is four. The averaged values in degrees C of input channels CH1 and CH2 stored respectively in data registers D0 and D3.
216
Stone Wu 3.1 217 **Example 1**
Leo Wei 1.1 218
219 This initial step checks that the special function block placed at position 2 is actually an LX3V-4TC, i.e. its unit identification number is 2030 (BFM #30). This step is optional, but it provides a software check that the system has been configured correctly.
220
221 (% style="text-align:center" %)
Stone Wu 3.1 222 [[image:LX3V-4TC_html_43f51c728463fc8c.png||height="149" width="500" class="img-thumbnail"]]
Leo Wei 1.1 223
224 * Specify the type of thermocouple, H3310 -> Block No.2 BFM#0. CH3 & CH4 are not used; CH2: Type J (1); CH1: Type K (0);
225 * Block No.2 BFM#30->(D2) identification code;
226 * When (K2030)= (D2), M1=ON. i.e. when identification code is K2030, M1=ON.
227
Stone Wu 3.1 228 **Example 2**
229
Leo Wei 1.1 230 Transfer the error status to (M25 to M10), when error is found, M10=ON
231
232 (% style="text-align:center" %)
Stone Wu 3.1 233 [[image:LX3V-4TC_html_8e3386c1b560c12a.png||height="107" width="500" class="img-thumbnail"]]
Leo Wei 1.1 234
235 This step provides optional monitoring of the LX3V-4TC Error Buffer Memory (#29). If there is an Error on the LX3V-4TC, bit b0 of BFM #29 will be set on. This can be read by this program step, and output as a bit device in the PLC (Y010 in this example). Additional Error devices can be output in a similar manner, e.g. b10 BFM #29 Digital range error. (see example 3)
236
Stone Wu 3.1 237 **Example 3**
Leo Wei 1.1 238
239 M10 represents b0 of BFM#29
240
241 M20 represents b10 of BFM#29
242
243 (% style="text-align:center" %)
Stone Wu 3.1 244 [[image:LX3V-4TC_html_15bac225fffa5e5.png||height="129" width="500" class="img-thumbnail"]]
Leo Wei 1.1 245
246 (% style="text-align:center" %)
Stone Wu 3.1 247 [[image:LX3V-4TC_html_d59884b711c0f883.png||height="149" width="500" class="img-thumbnail"]]
Leo Wei 1.1 248
249 * (K4)-> (BFM#1), (K4)-> (BFM#2). Number of samples is changed to 4 on both CH1 and CH2.
250 * (BFM#5)-> (D0), (BFM#6)-> (D1). Transfer the average temperature value in °C to the data registers.
251
252 This step is the actual reading of the LX3V-4TC input channels. It is essentially the only program step which is needed. The "TO" instruction in this example, sets the input channels, CH1 and CH2, to take the average reading of four samples.
253
254 The "FROM" instruction reads the average temperatures (BFM #5 to #8) for input channels CH1 and CH2 of the LX3V-4TC. If direct temperature readings are required BFM #9 and #10 should be read instead, e.g.
255
256 (% style="text-align:center" %)
Stone Wu 3.1 257 [[image:LX3V-4TC_html_24b3ab2479ed3b38.png||height="126" width="500" class="img-thumbnail"]]
Leo Wei 1.1 258
259 = **6 Diagnostics** =
260
261 **Preliminary checks**
262
263 1. Check whether the input wiring and/or extension cables are properly connected on LX3V-4TC analog special function block.
264 1. Check that the LX3V system configuration rules have not been broken, i.e. the number of special function blocks does not exceed 16 and the total system I/O is equal or less than 256 I/O.
265 1. Ensure that the correct operating range has been selected for the application.
266 1. Check that there is no power overload on either the 5V or 24V power sources, remember the loading on a LX3V main unit or a powered extension unit varies according to the number of extension blocks or special function blocks connected.
267 1. Put the LX3V main unit into RUN.
268
269 **Error checking**
270
Stone Wu 3.1 271 If the LX3V-4TC special function block does not seem to operate normally, check the following items.
Leo Wei 1.1 272
273 Check the status of the POWER LED.
274
275 Lit: The extension cable is properly connected.
276
277 Otherwise: Check the connection of the extension cable.
278
279 * Check the external wiring.
280 * Check the status of the “24V” LED (top right corner of the LX3V-4TC).
281
282 Lit: LX3V-4TC is OK; 24V DC power source is OK.
283
284 Otherwise: Possible 24VDC power failure, if OK possible LX3V-4TC failure.
285
286 * Check the status of the “A/D” LED (top right corner of the LX3V-4TC).
287
288 Lit: A/D conversion is proceeding normally.
289
290 Otherwise: Check buffer memory #29 (error status). If any bits (b2 and b3) are ON, then this is why the A/D LED is OFF.
291
Stone Wu 3.1 292 **Checking special function block numbers**
Leo Wei 1.1 293
294 Other special units of blocks that use FROM/TO commands, such as analog input blocks, analog output blocks and high-speed counter blocks, can be directly connected to the base unit of the LX3V programmable controller or to the right side of other extension blocks or units. Each special block is consecutively numbered from 0 to 15 beginning from the one closest to the base unit. A maximum of 16 special blocks can be connected.
295
296 (% style="text-align:center" %)
Stone Wu 3.1 297 [[image:LX3V-4TC_html_82dc23faccc052c2.png||height="349" width="1000" class="img-thumbnail"]]
Leo Wei 1.1 298
299 = **7 EMC considerations** =
300
301 * Electromagnetic compatibility or EMC must be considered before using the LX3V-4TC.
302 * WECON recommends that the thermocouple sensors used, should be fitted with a form of seild or screening as protection against EMC noise.
303 * If some form of cable protection is used, the “Shield” must be terminated at the terminals as shown in chapter 3.
304 * Because of the delicate nature of all analog signals, failure to take good EMC precautions could lead to EMC noise induced errors; up to ±10% of actual values. This is an absolute worst case figure, users who do take good precautions can expect operation within normal tolerances. EMC considerations should include selection of good quality cables, good routing of those cables away from potential noise sources.
305 * Additionally it is recommended that signal averaging is used as this will reduce the effects of random noise “spikes”