ProSoft Technology MVI69L-MBTCP - Manual (Page 114)

Reference MVI69L-MBTCP ♦ CompactLogix Platform
User Manual Communication Module
Page 114 of 152 ProSoft Technology, Inc.
January 6, 2014
The use of Server address 00 (Broadcast Mode) will force all attached Servers to
modify the desired coil.
Note: Functions 5, 6, 15, and 16 are the only messages that will be recognized as valid for
broadcast.
The example below is a request to Server number 11 to turn ON coil 0173.
Node
Address Function
Code Data Start
Point High Data Start
Point Low Number of
Points High Number of
Points Low Error Check
Field (2 bytes)
0B 05 00 AC FF 00 CRC
Response
The normal response to the Command Request is to re-transmit the message as
received after the coil state has been altered.
Node
Address Function
Code Data Coil Point
High Data Coil Point
Low Data On/
Off Data Error Check
Field (2 bytes)
0B 05 00 AC FF 00 CRC
The forcing of a coil via MODBUS function 5 will be accomplished regardless of
whether the addressed coil is disabled or not (In ProSoft products, the coil is only
affected if the necessary ladder logic is implemented).
Note: The Modbus protocol does not include standard functions for testing or changing the
DISABLE state of discrete inputs or outputs. Where applicable, this may be accomplished via
device specific Program commands (In ProSoft products, this is only accomplished through ladder
logic programming).
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".