Evolution Controls EVO/ECM-Modbus - Write Multiple Registers Command (16)

©Evolution
Controls Inc.
10-Sept-2020
EVO/™ECM-Modbus RTU Series 2 Page 22
Application Guide
©2020 All Rights Reserved
Evolution Controls Inc.
San Diego, CA USA
Read Multiple Coil Registers Command (01)
Address
Command
Code
Starting Register
Number of Registers
Error Check
1-247
01
00
00
00
34
CRC-16
• Unit, group 1, or group 2 address must be 1-247 (one byte)
• The command code is 01 (one byte).
• The starting register is two bytes long. The value must be 00 00 when addressing an EVO/ECM-
Modbus RTU.
• The number of registers is two bytes in length. The high byte is always 00. The low byte is
always 34 reading all 34 coil registers.
Reply to Modbus Master
Byte
Data
Address
Command
Code
Count
Coil 1-8
Coil 9-16
Coil 17-24
Coil 25-32
Coil 33-40
Error
Check
1-247
01
5
HI
LO
HI
LO
HI
LO
HI
LO
HI
LO
CRC-16
• The byte count is 5 bytes. The more significant bits contain the higher coil variables. Coil 35 to
40 are not used.