Watlow CPC400 - Manual (Page 208)

Appendix A: Modbus Protocol CPC400 Series User’s Guide
194 Watlow Anafaze Doc. 0600-2900-2000
Write Examples
The data written is echoed back to the controller. The fol-
lowing examples show sample query and response packets.
Example 1
The host query (Table A.5 on page 194) uses the multiple-
point write function to write a value of 20 to the proportion-
al band for loop 1 in a controller with address 1. The slave
responds (Table A.6 on page 194).
Table A.5 Sample Packet for Host Query
Table A.6 Sample Packet for Slave Response
Example 2
The host query (Table A.7 on page 194) uses the multiple-
point write function to write the values 30, 40, and 50 to the
proportional bands for loops 1 through 3 in a controller
with address 1. The slave responds (Table A.8 on page 194).
Table A.7 Sample Packet for Host Query
Table A.8 Sample Packet for Slave Response
Slave Address Function
Start Address Data
CRC
High Low High Low
04 06 00 00 00 14 89 90
Slave Address Function
Start Address Data
CRC
High Low High Low
04 06 00 00 00 14 89 90
Slave
Addr. Func-
tion
Start
Address
No. of
Registers Byte
Count
Data 1 Data 2 Data 3
CRC
Hi Lo Hi Lo Hi Lo Hi Lo Hi Lo
01 10 00 00 00 03 06 00 1E 00 28 00 32 4F 5F
Slave Address Function
Start Address Number of Registers
CRC
High Low High Low
01 10 00 00 00 03 80 08