Flowserve MX-100 Field Unit - Manual (Page 17)

17
MX/DDC-100 Field Unit Installation and Maintenance FCD LMENIM2329-01 – 03/11
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Table 2.3 – Status Bit Definitions (continued)
Bit Number
Modbus
Bit
Address
MX/DDC
205 204 Lost Phase Input
206 205 Phase Reverse Input
207 206 Not used
208 207 PB DP board present
Example
Poll field unit number 22 for 16 inputs starting at input 129 with the actuator opening.
Query: 1602008000107B09
Response: 1602020108CDED
Message Breakdown
Query Response
16 Slave (Field Unit) Address 16 Slave (Field Unit) Address
02 Function 02 Function
00 Starting Address Hi 02 Byte Count
80 Starting Address Lo 01 1 Data (Inputs 10136 - 10129)
00 No. of Points Hi 08
2
Data (Inputs 10144 - 10137)
10 No. of Points Lo CDED Error Check (CRC)
7B09 Error Check (CRC)
Note 1: 01h equals 0000 0001 (actuator open input bit is ON).
Note 2: 08h equals 0000 1000 (actuator Channel B Fail bit is ON).
2.3.5 Modbus Function Code 03 (Read Holding Register)
This function code is used to read the binary contents of holding registers in the DDC-100 Field Unit. This function
code is typically used during the network polling cycle. A network poll should consist of field unit registers 9 (Status)
and 10 (Fault) as a minimum. Holding register 8 should also be polled when the actuator is configured for the analog
feedback option or position control. See Table 2.4 for a complete listing of the holding registers.