Flowserve MX-100 Field Unit - Manual (Page 28)

MX/DDC-100 Field Unit Installation and Maintenance FCD LMENIM2329-01 – 03/11
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Message Breakdown
Query Response
01 Slave Address 01 Slave Address
0F Function 0F Function
00 Coil Address Hi 00 Coil Address Hi
00 Coil Address Lo 00 Coil Address Lo
00 Quantity of Coils Hi 00 Quantity of Coils Hi
01 Quantity of Coils Lo 01 Quantity of Coils Lo
01 Byte Count 940B Error Check (LRC or CRC)
01 Force Data Lo
EF57 Error Check (LRC or CRC)
Note: 000000010101h equals Coil Address 00000001 (field unit coil 1)
000100010101h equals Coil Address 00000010 (field unit coil 2)
2.3.11 Modbus Function Code 16 (Preset Multiple Registers)
This function code is used to preset single or multiple registers in the field unit and uses the same predetermined
register values as the function code 06. This function code is typically used to command the DDC-100 Field Unit by
writing values to the 40001 and/or 40002 registers.
Modbus function code 16 command values for controlling the DDC-100 Field Unit are given in Table 2.6. Each
command should be issued only one time for the desired field unit control. Repeated issuance of an acknowledged
command will degrade network performance.
The normal response returns the slave address, function code, starting address, and quantity of registers preset.
NOTE: This function code is implemented in DDC Modbus Firmware 2.00 and greater and MX-DDC Firmware
02/01.00 and greater.
Example of Field Unit Command
Write the command to open an actuator (actuator open) to field unit number 1. This corresponds to writing the value
256 into field unit register 40001.
Query: 011000000001020100A7C0
Response: 01100000000101C9
Message Breakdown
Query Response
01 Slave Address 01 Slave Address
10 Function 10 Function
00 Starting Address Hi 00 Starting Address Hi
00 Starting Address Lo 00 Starting Address Lo
00 Number of Registers Hi 00 Number of Registers Hi
01 Number of Registers Lo 01 Number of Registers Lo
02 Byte Count 01C9 Error Check (LRC or CRC)
01 Preset Data Hi
00 Preset Data Lo
A7C0 Error Check (LRC or CRC)