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Wiki source code of 08 Communication

Version 1.1 by Leo Wei on 2022/06/08 12:57
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1 The VD2 series servo drive has Modbus communication function, which could cooperate with the host computer for parameter modification, parameter query, monitoring volume servo status query and control. The servo drive is used as a slave device.
2
3 = **Modbus communication** =
4
5 == **Hardware wiring** ==
6
7 The position of RS485 communication port (take VD2B as an example) is as the figure below.
8
9 [[image:http://docs.we-con.com.cn/wiki/servo/download/2.%20User%20Manual/06%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29/WebHome/Wecon%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29_html_6583b880b8115df0.gif?rev=1.1||alt="Wecon VD2 SA Series Servo Drives Manual (Full V1.1)_html_6583b880b8115df0.gif"]]
10
11 Figure 8-1 The position of RS485 communication port of VD2B drive
12
13 For the position of the RS485 communication port of other models, see __[[4.5 Communication signal wiring>>http://13.229.109.52:8080/wiki/servo/view/2.%20User%20Manual/06%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29/04%20Wiring/#HCommunicationsignalwiring]]__.
14
15 The servo drive adopts RS485 half-duplex communication mode. The 485 bus should adopt the hand-in-hand structure instead of the star structure or the bifurcated structure. The star structure or bifurcation structure will produce reflected signals, which will affect the 485 communication.
16
17 (% class="table-bordered" %)
18 |(% style="text-align:center; vertical-align:middle" %)[[image:http://docs.we-con.com.cn/wiki/servo/download/2.%20User%20Manual/06%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29/WebHome/Wecon%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29_html_6db94f5d0421f97a.png?rev=1.1||alt="Wecon VD2 SA Series Servo Drives Manual (Full V1.1)_html_6db94f5d0421f97a.png"]]
19 |(((
20 ✎The wiring must use shielded twisted pair, stay away from strong electricity, do not run in parallel with the power line, let alone bundle it together!
21
22 ✎In a half-duplex connection, only one servo drive can communicate with the host computer at the same time. If two or more servo drives upload data at the same time, bus competition will occur. Not only will it lead to communication failure, it may also cause some components to generate large currents and damage the components.
23 )))
24
25 [[image:http://docs.we-con.com.cn/wiki/servo/download/2.%20User%20Manual/06%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29/WebHome/Wecon%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29_html_ec4180b4b0c8dd01.gif?rev=1.1||alt="Wecon VD2 SA Series Servo Drives Manual (Full V1.1)_html_ec4180b4b0c8dd01.gif"]]
26
27 Figure 8-2 RS485 communication network wiring diagram
28
29 The terminal of RS485 network should use a terminating resistors of 120Ω to weaken the reflection of the signal. Intermediate networks cannot use terminating resistors.
30
31 No point in the RS485 network can be directly grounded. All devices in the network must be well grounded through their own grounding terminals.
32
33 (% class="table-bordered" %)
34 |(% style="text-align:center; vertical-align:middle" %)[[image:http://docs.we-con.com.cn/wiki/servo/download/2.%20User%20Manual/06%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29/WebHome/Wecon%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29_html_6db94f5d0421f97a.png?rev=1.1||alt="Wecon VD2 SA Series Servo Drives Manual (Full V1.1)_html_6db94f5d0421f97a.png"]]
35 |Under no circumstances can the grounding wire form a closed loop.
36
37 When wiring, consider the drive capability of the computer/PLC and the distance between the computer/PLC and the servo drive. If the drive capacity is insufficient, a repeater is needed.
38
39 = **Modbus communication protocol analysis** =
40
41 == **Modbus data frame format** ==
42
43 The VD2 series servo drives currently support the RTU communication format. The typical data frame format is shown in the table.
44
45 (% class="table-bordered" %)
46 |(% rowspan="2" style="text-align:center; vertical-align:middle; width:425px" %)**There should be a message interval not less than 3.5 characters at the beginning**|(% style="text-align:center; vertical-align:middle; width:166px" %)**Address**|(% style="text-align:center; vertical-align:middle; width:189px" %)**Function code**|(% style="text-align:center; vertical-align:middle; width:155px" %)**Data**|(% style="text-align:center; vertical-align:middle; width:158px" %)**CRC check code**
47 |(% style="text-align:center; vertical-align:middle; width:166px" %)1 byte|(% style="text-align:center; vertical-align:middle; width:189px" %)1 byte|(% style="text-align:center; vertical-align:middle; width:155px" %)N bytes|(% style="text-align:center; vertical-align:middle; width:158px" %)2 bytes
48
49 == **Description of supported function codes** ==
50
51 The host reads and writes data to the servo through Modbus RTU format (03, 06 function codes). The corresponding Modbus function codes are as follows:
52
53 (% class="table-bordered" %)
54 |(% style="text-align:center; vertical-align:middle" %)**Operate**|(% style="text-align:center; vertical-align:middle" %)**Command code**
55 |(% style="text-align:center; vertical-align:middle" %)Read 16-bit function code|(% style="text-align:center; vertical-align:middle" %)0x03
56 |(% style="text-align:center; vertical-align:middle" %)Write 16-bit function code|(% style="text-align:center; vertical-align:middle" %)0x06
57
58 **(1) Read function code: 0x03**
59
60 Request format:
61
62 (% class="table-bordered" %)
63 |(% style="text-align:center; vertical-align:middle; width:84px" %)**Address**|(% style="text-align:center; vertical-align:middle; width:104px" %)**Function code**|(% style="text-align:center; vertical-align:middle; width:179px" %)(((
64 **Initial address high byte**
65 )))|(% style="text-align:center; vertical-align:middle; width:162px" %)(((
66 **Initial address low byte**
67 )))|(% style="text-align:center; vertical-align:middle; width:194px" %)(((
68 **Number of reads high byte**
69 )))|(% style="text-align:center; vertical-align:middle; width:195px" %)(((
70 **Number of reads low byte**
71 )))|(% style="text-align:center; vertical-align:middle; width:158px" %)**CRC check code**
72 |(% style="text-align:center; vertical-align:middle; width:84px" %)1 byte|(% style="text-align:center; vertical-align:middle; width:104px" %)03|(% style="text-align:center; vertical-align:middle; width:179px" %)1 byte|(% style="text-align:center; vertical-align:middle; width:162px" %)1 byte|(% style="text-align:center; vertical-align:middle; width:194px" %)1 byte|(% style="text-align:center; vertical-align:middle; width:195px" %)1 byte|(% style="text-align:center; vertical-align:middle; width:158px" %)2 bytes
73
74 Correct response format:
75
76 (% class="table-bordered" %)
77 |(% style="text-align:center; vertical-align:middle; width:85px" %)**Address**|(% style="text-align:center; vertical-align:middle; width:139px" %)**Function code**|(% style="text-align:center; vertical-align:middle; width:244px" %)(((
78 **Return data number of bytes**
79 )))|(% style="text-align:center; vertical-align:middle; width:203px" %)(((
80 **Register 1 high byte**
81 )))|(% style="text-align:center; vertical-align:middle; width:190px" %)(((
82 **Register 1 low byte**
83 )))|(% style="text-align:center; vertical-align:middle; width:72px" %)…|(% style="text-align:center; vertical-align:middle; width:143px" %)**CRC check code**
84 |(% style="text-align:center; vertical-align:middle; width:85px" %)1 byte|(% style="text-align:center; vertical-align:middle; width:139px" %)03|(% style="text-align:center; vertical-align:middle; width:244px" %)1 byte|(% style="text-align:center; vertical-align:middle; width:203px" %)1 byte|(% style="text-align:center; vertical-align:middle; width:190px" %)1 byte|(% style="text-align:center; vertical-align:middle; width:72px" %)…|(% style="text-align:center; vertical-align:middle; width:143px" %)2 bytes
85
86 **(2) Write function code: 0x06**
87
88 Request format:
89
90 (% class="table-bordered" %)
91 |(% style="text-align:center; vertical-align:middle" %)**Address**|(% style="text-align:center; vertical-align:middle" %)**Function code**|(% style="text-align:center; vertical-align:middle" %)**Register address high byte**|(% style="text-align:center; vertical-align:middle" %)**Register address low byte**|(% style="text-align:center; vertical-align:middle" %)**Data high byte**|(% style="text-align:center; vertical-align:middle" %)**Data low byte**|(% style="text-align:center; vertical-align:middle" %)**CRC check code**
92 |(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)06|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)2 bytes
93
94 Response format:
95
96 (% class="table-bordered" %)
97 |(% style="text-align:center; vertical-align:middle" %)**Address**|(% style="text-align:center; vertical-align:middle" %)**Function code**|(% style="text-align:center; vertical-align:middle" %)**Register address high byte**|(% style="text-align:center; vertical-align:middle" %)**Register address low byte**|(% style="text-align:center; vertical-align:middle" %)**Data high byte**|(% style="text-align:center; vertical-align:middle" %)**Data low byte**|(% style="text-align:center; vertical-align:middle" %)**CRC check code**
98 |(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)06|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)2 bytes
99
100 If the setting is successful, the original is returned
101
102 (% class="table-bordered" %)
103 |(% rowspan="2" style="text-align:center; vertical-align:middle" %)**There should be a message interval not less than 3.5 characters at the beginning**|(% style="text-align:center; vertical-align:middle" %)**Address**|(% style="text-align:center; vertical-align:middle" %)**Function code**|(% style="text-align:center; vertical-align:middle" %)**Data**|(% style="text-align:center; vertical-align:middle" %)**CRC check code**
104 |(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)N bytes|(% style="text-align:center; vertical-align:middle" %)2 bytes
105
106 == **CRC check** ==
107
108 The servo uses a 16-bit CRC check, and the host computer must also use the same check rule, otherwise the CRC check will make mistake. When transmitting, the low bit is in the front and the high bit is at the back. The CRC code are as follows:
109
110 {{code language="LUA"}}
111 {
112
113     Uint16 crc = 0xffff;
114
115     Uint16 i;
116
117
118
119   while(uLen--)
120
121   {
122
123     crc ^=(Uint16) *pBuf++;
124
125     for(i=0; i<8; i++)
126
127     {
128
129       if(crc & 0x0001)
130
131 {
132
133 crc = (crc >> 1) ^ 0xa001;
134
135 }
136
137 else
138
139 {
140
141 crc = crc >> 1;
142
143 }
144
145
146
147     }
148
149   }
150
151   return crc;
152
153 }
154
155 return crc;
156
157 }
158 {{/code}}
159
160 == **Error response frame** ==
161
162 (% class="table-bordered" %)
163 |(% style="text-align:center; vertical-align:middle" %)**Address**|(% style="text-align:center; vertical-align:middle" %)**Function code**|(% style="text-align:center; vertical-align:middle" %)**Error code**|(% style="text-align:center; vertical-align:middle" %)**CRC check code**
164 |(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)Command code+0x80|(% style="text-align:center; vertical-align:middle" %)Error code|(% style="text-align:center; vertical-align:middle" %)2 bytes
165
166 When an error occurs, set the function code bit7 issued by the host to 1, and return (for example, 0x03 returns 0x83, 0x06 returns 0x86); the description of the error code are as follows.
167
168 (% class="table-bordered" %)
169 |(% style="text-align:center; vertical-align:middle" %)**Error code**|(% style="text-align:center; vertical-align:middle" %)**Coding description**
170 |(% style="text-align:center; vertical-align:middle" %)0x0001|(% style="text-align:center; vertical-align:middle" %)Illegal command code
171 |(% style="text-align:center; vertical-align:middle" %)0x0002|(% style="text-align:center; vertical-align:middle" %)Illegal data address
172 |(% style="text-align:center; vertical-align:middle" %)0x0003|(% style="text-align:center; vertical-align:middle" %)Illegal data
173 |(% style="text-align:center; vertical-align:middle" %)0x0004|(% style="text-align:center; vertical-align:middle" %)Slave device failure
174
175 == **Communication example** ==
176
177 **03 Function Code Read**
178
179 Read the monitoring volume U0-31 bus voltage, the Modbus register address corresponding to this variable is 7716 (0x1E24)
180
181 Request format:
182
183 (% class="table-bordered" %)
184 |(% style="text-align:center; vertical-align:middle" %)**Address**|(% style="text-align:center; vertical-align:middle" %)**Function code**|(% style="text-align:center; vertical-align:middle" %)**Register address high byte**|(% style="text-align:center; vertical-align:middle" %)**Register address low byte**|(% style="text-align:center; vertical-align:middle" %)**Data high byte**|(% style="text-align:center; vertical-align:middle" %)**Data low byte**|(% style="text-align:center; vertical-align:middle" %)**CRC check code**
185 |(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)06|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)1 byte|(% style="text-align:center; vertical-align:middle" %)2 bytes
186
187 The slave responds normally:
188
189 (% class="table-bordered" %)
190 |(% style="text-align:center; vertical-align:middle" %)**Address**|(% style="text-align:center; vertical-align:middle" %)**Function code**|(% style="text-align:center; vertical-align:middle" %)**Number of bytes**|(% style="text-align:center; vertical-align:middle" %)**Data high byte**|(% style="text-align:center; vertical-align:middle" %)**Data low byte**|(% style="text-align:center; vertical-align:middle" %)**CRC low byte**|(% style="text-align:center; vertical-align:middle" %)**CRC high byte**
191 |(% style="text-align:center; vertical-align:middle" %)01|(% style="text-align:center; vertical-align:middle" %)03|(% style="text-align:center; vertical-align:middle" %)02|(% style="text-align:center; vertical-align:middle" %)0C|(% style="text-align:center; vertical-align:middle" %)26|(% style="text-align:center; vertical-align:middle" %)3C|(% style="text-align:center; vertical-align:middle" %)9E
192
193 The value read is 0x0C26, which means that the voltage is 311.0V.　
194
195 **06 Function Code Write**
196
197 P1-10 the maximum speed threshold is set to 3000rpm. This variable corresponds to the Modbus address: 266 (0x010A)
198
199 Request format:
200
201 (% class="table-bordered" %)
202 |(% style="text-align:center; vertical-align:middle" %)**Address**|(% style="text-align:center; vertical-align:middle" %)**Function code**|(% style="text-align:center; vertical-align:middle" %)**Register address high byte**|(% style="text-align:center; vertical-align:middle" %)**Register address low byte**|(% style="text-align:center; vertical-align:middle" %)**Data high byte**|(% style="text-align:center; vertical-align:middle" %)**Data low byte**|(% style="text-align:center; vertical-align:middle" %)**CRC low byte**
203 |(% style="text-align:center; vertical-align:middle" %)01|(% style="text-align:center; vertical-align:middle" %)06|(% style="text-align:center; vertical-align:middle" %)01|(% style="text-align:center; vertical-align:middle" %)0A|(% style="text-align:center; vertical-align:middle" %)0B|(% style="text-align:center; vertical-align:middle" %)B8|(% style="text-align:center; vertical-align:middle" %)AF
204
205 The slave responds normally:
206
207 |(% style="text-align:center; vertical-align:middle" %)**Address**|(% style="text-align:center; vertical-align:middle" %)**Function code**|(% style="text-align:center; vertical-align:middle" %)**Register address high byte**|(% style="text-align:center; vertical-align:middle" %)**Register address low byte**|(% style="text-align:center; vertical-align:middle" %)**Data high byte**|(% style="text-align:center; vertical-align:middle" %)**Data low byte**|(% style="text-align:center; vertical-align:middle" %)**CRC low byte**
208 |(% style="text-align:center; vertical-align:middle" %)01|(% style="text-align:center; vertical-align:middle" %)06|(% style="text-align:center; vertical-align:middle" %)01|(% style="text-align:center; vertical-align:middle" %)0A|(% style="text-align:center; vertical-align:middle" %)0B|(% style="text-align:center; vertical-align:middle" %)B8|(% style="text-align:center; vertical-align:middle" %)AF
209
210 = **Servo communication parameter setting** =
211
212 [[image:http://docs.we-con.com.cn/wiki/servo/download/2.%20User%20Manual/06%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29/WebHome/Wecon%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29_html_fd76131f4dd0361c.gif?rev=1.1||alt="Wecon VD2 SA Series Servo Drives Manual (Full V1.1)_html_fd76131f4dd0361c.gif"]]
213
214 Figure 8-3 Modbus communication parameter setting process
215
216 **(1) Set the servo address P12-1**
217
218 When multiple servos are in network communication, each servo can only have a unique address, otherwise it will cause abnormal communication and fail to communicate.
219
220 **(2) Set the serial port baud rate P12-2**
221
222 The communication rate of the servo and the communication rate of the host computer must be set consistently, otherwise the communication cannot be carried out.
223
224 **(3) Set the serial port data format P12-3**
225
226 The data bit check methods of servo communication are:
227
228 Odd parity
229
230 Even parity
231
232 No parity
233
234 The stop bit: 1 stop bit and 2 stop bits.
235
236 The data frame format of the servo and the host computer must be consistent, otherwise the communication cannot be carried out.
237
238 **(4) Set that whether the function code changed by Modbus communication is written into EEPROM in real time [P12-4]**
239
240 When the host computer modifies the servo function code through communication, it can choose to store it in EEPROM in real time, which has the function of power-off storage.
241
242 If the value of the function code only needs to be rewritten once, and the value is used later, the function of real-time writing of the function code to EEPROM can be enabled.
243
244 If you need to change the value of the function code frequently, it is recommended to turn off the function of real-time writing to EERPOM of function code, otherwise the EEPROM will be shortened due to frequent erasing and writing of the EEPROM.
245
246 (% class="table-bordered" %)
247 |(% style="text-align:center; vertical-align:middle" %)[[image:http://docs.we-con.com.cn/wiki/servo/download/2.%20User%20Manual/06%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29/WebHome/Wecon%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29_html_6db94f5d0421f97a.png?rev=1.1||alt="Wecon VD2 SA Series Servo Drives Manual (Full V1.1)_html_6db94f5d0421f97a.png"]]
248 |After the EEPROM is damaged, the servo will have an non resettable fault!
249
250 **(5) Set the high and low order of the 32-bit monitoring data**
251
252 Part of the monitoring volume is 32-bit length and occupies 2 consecutive bias numbers. The user needs to set the order of the data high bit and low bit correctly, otherwise it will cause data reading and writing errors!
253
254 For example, U0-54 (position within 1 circle of absolute encoder) occupies two consecutive offset numbers, which are 0x1E3D and 0x1E3E respectively. Assuming the value of U0-54 is 0x12345678, the correct data sequence bit should be 0x1E3D=0x5678 , 0x1E3E=0x1234 (little endian mode: low byte first, high byte behind.)
255
256 The description of related function codes are as follows.
257
258 (% class="table-bordered" %)
259 |(% style="text-align:center; vertical-align:middle; width:121px" %)**Function code**|(% style="text-align:center; vertical-align:middle; width:205px" %)**Name**|(% style="text-align:center; vertical-align:middle; width:135px" %)(((
260 **Setting method**
261 )))|(% style="text-align:center; vertical-align:middle; width:171px" %)(((
262 **Effective time**
263 )))|(% style="text-align:center; vertical-align:middle; width:115px" %)**Default value**|(% style="text-align:center; vertical-align:middle; width:61px" %)**Range**|(% style="text-align:center; vertical-align:middle; width:347px" %)**Definition**|(% style="text-align:center; vertical-align:middle" %)**Unit**
264 |(% style="text-align:center; vertical-align:middle; width:121px" %)P12-02|(% style="text-align:center; vertical-align:middle; width:205px" %)Baud rate|(% style="text-align:center; vertical-align:middle; width:135px" %)(((
265 Operation setting
266 )))|(% style="text-align:center; vertical-align:middle; width:171px" %)(((
267 Effective immediately
268 )))|(% style="text-align:center; vertical-align:middle; width:115px" %)2|(% style="text-align:center; vertical-align:middle; width:61px" %)0 to 5|(% style="width:347px" %)(((
269 0-2400bps
270
271 1-4800bps
272
273 2-9600bps
274
275 3-19200bps
276
277 4-38400bps
278
279 5-57600bp
280 )))|(% style="text-align:center; vertical-align:middle" %)-
281 |(% style="text-align:center; vertical-align:middle; width:121px" %)P12-03|(% style="text-align:center; vertical-align:middle; width:205px" %)Serial data format|(% style="text-align:center; vertical-align:middle; width:135px" %)(((
282 Operation setting
283 )))|(% style="text-align:center; vertical-align:middle; width:171px" %)(((
284 Effective immediately
285 )))|(% style="text-align:center; vertical-align:middle; width:115px" %)0|(% style="text-align:center; vertical-align:middle; width:61px" %)0 to 3|(% style="width:347px" %)(((
286 0: 1 stop bit, no parity
287
288 1: 1 stop bit, odd parity
289
290 2: 1 stop bit, even parity
291
292 3: 2 stop bits, no parity
293 )))|(% style="text-align:center; vertical-align:middle" %)-
294 |(% style="text-align:center; vertical-align:middle; width:121px" %)P12-04|(% style="text-align:center; vertical-align:middle; width:205px" %)Modbus communication data is written into EEPROM|(% style="text-align:center; vertical-align:middle; width:135px" %)(((
295 Operation setting
296 )))|(% style="text-align:center; vertical-align:middle; width:171px" %)(((
297 Effective immediately
298 )))|(% style="text-align:center; vertical-align:middle; width:115px" %)0|(% style="text-align:center; vertical-align:middle; width:61px" %)0 to 1|(% style="width:347px" %)(((
299 0: Do not write to EEPROM, and do not store after power failure;
300
301 1: Write to EEPROM, power-down storage.
302 )))|(% style="text-align:center; vertical-align:middle" %)-
303
304 = **Modbus communication variable address and value** =
305
306 == **Variable address description** ==
307
308 Modbus registers are divided into two categories:
309
310 ~1. The first category is servo function code parameters (address: 0x0001 to 0x0D08), this part of the register is readable and writable (that is, 0x03 and 0x06 are supported);
311
312 2. The second category is the monitoring volume of the servo (address: 0x1E01 to 0x2010), this part of the register is only readable (0x03 function is supported).
313
314 **Servo function code representation: PXX-YY.**
315
316 XX: represents the function code group number,
317
318 YY: represents the bias within the function code group;;
319
320 During servo communication, the communication address of the function code is a 16-bit address, which is composed of the function code group number (high 8 bits) + group bias (low 8 bits), for example, the Modbus address corresponding to P12-1 (servo address) is 0x0C01.
321
322 **Servo monitor volume representation: Uxx-yy.**
323
324 xx: represents the monitoring volume group number,
325
326 yy: represents the bias within the monitoring volume group;
327
328 During Modbus communication, the starting address of the monitoring volume is 0x1E01, and the conversion relationship of the address is similar to the representation way of the function code.
329
330 For example, U0-01 (servo status) corresponds to the Modbus address is 0x1E01.
331
332 In order to facilitate actual use, this manual provides both decimal and hexadecimal address identification, it is shown in the following table:
333
334 (% class="table-bordered" %)
335 |(% style="text-align:center; vertical-align:middle" %)**Function code**|(% style="text-align:center; vertical-align:middle" %)(((
336 **Modbus address**
337
338 **(Hexadecimal)**
339 )))|(% style="text-align:center; vertical-align:middle" %)(((
340 **Modbus address**
341
342 **(Decimal)**
343 )))|(% style="text-align:center; vertical-align:middle" %)**Category**|(% style="text-align:center; vertical-align:middle" %)**Name**
344 |(% style="text-align:center; vertical-align:middle" %)P0-1|(% style="text-align:center; vertical-align:middle" %)0x0001|(% style="text-align:center; vertical-align:middle" %)1|(% style="text-align:center; vertical-align:middle" %)Basic settings|(% style="text-align:center; vertical-align:middle" %)Control mode
345
346 For detailed parameter addresses, please refer to __[["11.1 Lists of parameters".>>http://13.229.109.52:8080/wiki/servo/view/2.%20User%20Manual/06%20VD2%20SA%20Series%20Servo%20Drives%20Manual%20%28Full%20V1.1%29/11%20Appendix/#HListsofparameters]]__
347
348 == **Variable value type description** ==
349
350 When writing function codes with signed numbers, you need to convert the pre-written data into hexadecimal complements. The conversion rules are as follows:
351
352 ~1. The data is positive or 0: complement code = original code
353
354 2. The data is negative: complement code = 0xFFFF-absolute value of data + 0x0001
355
356 For example,The 16-bit signed positive number +100, the original code is 0x0064, and the complement is: 0x0064. The 16-bit signed positive number -100, its hexadecimal complement is: 0xFFFF-0x0064 + 0x0001 = 0xFF9C.
357
358 If it is an unsigned number, just pass it directly according to its original code. For example, if the decimal number is 32768, write 0x8000 directly.
359
360 == **Numerical unit description** ==
361
362 Some values have units and decimals, such as 0.1%, 0.1Hz, 0.01ms, and the corresponding value conversion is required when reading and writing. The methods are as follows:
363
364 ~1. When the unit is 0.1%: 1 represents 0.1%, 10 represents 1.0%, 1000 represents 100.0%. Therefore, writing 1000 means setting to 100.0%; on the contrary, if it is reading 1000, it means that the value is 100.0%;
365
366 2. When the unit is 0.01ms: 1 means 0.01ms, 50 means 0.5ms, 10000 means 100ms. Therefore, writing 1000 means setting to 10.00ms; on the contrary, if 1000 is read, it means 10.00ms; The other units can be deduced by this, and integer remains unchanged.