10 modbus function code 15 (force multiple coils) – Flowserve MX-100 Field Unit User Manual
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MX/DDC-100 Field Unit Installation and Maintenance FCD LMENIM2329-01 – 03/11
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Message Breakdown
Query
Response
03
Slave (Field Unit) Address
03
Slave (Field Unit) Address
08
Function
08
Function
00
Subfunction Hi
00
Subfunction Hi
00
Subfunction Lo
00
Subfunction Lo
00
Data Hi
00
Data Hi
00
Data Lo
00
Data Lo
E1E9
Error Check (CRC)
E1E9
Error Check (CRC)
Table 2.7 – Diagnostic Codes Supported by the DDC-100 Field Unit
Code
Name
00
Return Query Data
01
Restart Communication Option
02
Return Diagnostic Register
1
03
Change ASCII Input Delimiter
04
Force Listen-Only Mode
10 (0A Hex)
Clear Counters and Diagnostics Register
11 (0B Hex)
Return Bus Message Count
12 (0C Hex)
Return Bus Communication Error Count
13 (0D Hex)
Return Bus Exception Error Count
14 (0E Hex)
Return Slave Message Count
Note 1: Contains DDC-100 Field Unit diagnostic information. For engineering use only.
2.3.10 Modbus Function Code 15 (Force Multiple Coils)
This function code allows the user to force multiple coils with a single command and uses the same coil assignments
as the function code 05.
It should be noted that the coils are operated from the lowest coil number to the highest. Forcing coil 1 or 2 OFF (0) is
considered a stop command, sending a 15 command to force two coils starting with coil 1, with coil 1 ON and coil 2
OFF, would result in the unit stopping, since coil 2 is forced OFF after coil 1 is forced ON.
To prevent inadvertent Stop commands from being issued, it is recommended to force one coil at a time.
Available digital outputs for DDC-100 Field Units are listed in Table 2.5. Force multiple coil commands should be
issued only once for the desired field unit control. Repeated issuance of an acknowledged command will degrade
network performance.
NOTE: This function code is implemented in UEC-3-DDC Modbus Firmware 2.00 and greater and MX-DDC Firmware
02/01.00 and greater
Example of force coil command
Force coil 1 of field unit 1 ON. This will CLOSE the valve controlled by field unit 1.
Query: 010F000000010101EF57
Response: 010F00000001940B