ProSoft Technology MVI56E-MNETC - Manual (Page 151)

MVI56E-MNETC ♦ ControlLogix Platform Reference
Modbus TCP/IP Client Enhanced Communication Module User Manual
ProSoft Technology, Inc. Page 151 of 183
February 3, 2013
Coils that are reprogrammed in the controller logic program are not automatically
cleared upon power up. Thus, if such a coil is set ON by function Code 5 and
(even months later), an output is connected to that coil, the output will be "hot".
5.5.7 Preset Single Register (Function Code 06)
Query
Function (06) allows the user to modify the contents of a holding register. Any
holding register that exists within the controller can have its contents changed by
this message. However, because the controller is actively scanning, it also can
alter the content of any holding register at any time. The values are provided in
binary up to the maximum capacity of the controller unused high order bits must
be set to zero. When used with server address zero (Broadcast mode) all server
controllers will load the specified register with the contents specified.
Note Functions 5, 6, 15, and 16 are the only messages that will be recognized as
valid for broadcast.
Adr Func Data Start
Reg Hi
Data Start
Reg Lo Data #of Regs
Hi Data #of Regs
Lo Error Check
Field
11 06 00 01 00 03 CRC
Response
The response to a preset single register request is to re-transmit the query
message after the register has been altered.
Adr Func Data Reg
Hi
Data Reg
Lo Data Input Reg
Hi Data Input Reg
Lo Error Check Field
11 06 00 01 00 03 CRC