Read Coils Service (4C Hex) - Comtrol DeviceMaster EtherNet/IP-Modbus EIP-MOD User Manual

| Read Coils Service (4C Hex)

10.2. Read Coils Service (4C Hex)
This service reads one or more coils from the Modbus Coils table. This service results in the DeviceMaster
EIP-MOD issuing a Read Coils function (function code 0x01) to either the Shared Memory or the Modbus
Message Routing subsystem. Refer to CIP Standard Vol1_3.22 Section 5B-3 and/or MODBUS Application
Protocol Specification V1.1b3.pdf at
Parameter
Service Code
Instance
Class
Attribute
Source Element RdCoilsReqData
Source Length
Destination
DeviceMaster EIP-MOD User Guide: 2000664 Rev. A
www.modbus.org
Value
4C hex
8
44 hex
0
4
RdCoilsRespData
for more details.
Description
Directly corresponds to Modbus function code:
Read Coils (function code 1)
Modbus Device ID of 8
(Valid Range = 1 to 255)
Modbus Object
Not used
Tag of structure type RdCoilsRequest
Length in bytes of RdCoilsReqData
Tag of structure type RdCoilsResponse
Chapter 10. PLC Programming for Modbus Object (44 Hex) - 129