Flowserve MX-100 Field Unit - Manual (Page 26)

MX/DDC-100 Field Unit Installation and Maintenance FCD LMENIM2329-01 – 03/11
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To move the actuator to a position of 50%, place the value 0x4B in the high byte and the value of 0x32 (50 decimal) •
into the low byte.
Example:
Hex format: 0x4B32
To use the decimal method of determining a single write “move-to” command, add the desired position value to
19200.
Example:
Desired position: 50%
19200 + 50 = 19250
Example of single write “move-to” command
Move an actuator at address 1 to 50% of open by writing the value of 19250 (0x4B32) to the field unit 40001 register.
The actuator will then move to a position of 50% open.
Example
Query: 010600004B323EEF
Response: 010600004B323EEF
Message Breakdown
Query Response
01 Slave Address 01 Slave Address
06 Function 06 Function
00 Starting Address Hi 00 Starting Address Hi
00 Starting Address Lo 00 Starting Address Lo
4B Preset Data Hi 4B Preset Data Hi
32 Preset Data Lo 32 Preset Data Lo
3EEF Error Check (LRC or CRC) 3EEF Error Check (LRC or CRC)
2.3.9 Modbus Function Code 08 (Diagnostics)
This function code provides a series of tests for checking the communication system between the Host and field units
(slaves), or for checking various error conditions within the field unit. This function code uses a two-byte subfunction
code field in the query to define the type of test to be performed. The field unit echoes both the function code and
subfunction code in a normal response. It does not affect the field unit in any way. If this exchange is successful, then
the communication is successful.
A listing of the supported diagnostic two-byte subfunction codes is given in Table 2.7.
Example
Request a loopback (return query data) from the field unit at network address 3.
Query: 030800000000E1E9
Response: 030800000000E1E9