ProSoft Technology MVI71-MNET - Manual (Page 94)

MVI71-MNET ♦ PLC Platform Reference
Modbus TCP/IP Interface Module User Manual
Page 94 of 109
ProSoft Technology, Inc.
June 23, 2009
The data fields in responses to other kinds of queries could contain error counts
or other data requested by the sub-function code.
5.7.8 Force Multiple Coils (Function Code 15)
Query
This message forces each coil in a consecutive block of coils to a desired ON or
OFF state. Any coil that exists within the controller can be forced to either state
(ON or OFF). However, because the controller is actively scanning, unless the
coils are disabled, the controller can also alter the state of the coil. Coils are
numbered from zero (coil 00001 = zero, coil 00002 = one, and so on). The
desired status of each coil is packed in the data field, one bit for each coil (1=
ON, 0= OFF). The use of Slave address 0 (Broadcast Mode) will force all
attached Slaves to modify the desired coils.