ProSoft Technology MVI46-MBP - Manual (Page 46)

MVI46-MBP ♦ SLC Platform Reference
Modbus Plus Communication Module
Page 46 of 101 ProSoft Technology, Inc.
February 19, 2008
Warm Boot
This command is sent from the SLC processor to the module's control register
(4370) in the M1 file by inserting a value of 9998 into the register. When the
module recognizes this value in the control register it performs the warm-boot
operation and sets the register to a value of zero.
Cold Boot
This command is sent from the SLC processor to the module's control register
(4370) in the M1 file by inserting a value of 9999 into the register. When the
module recognizes this value in the control register it performs the cold-boot
operation and sets the register to a value of zero.
5.2.2 Pass-Through Control Blocks
Formatted Pass Through Control Blocks
If the port on the module is configured for the formatted pass-through mode, the
module will pass blocks with identification codes of 9956 = FC16, and 9958 =
FC5, and 9959 = FC15 to the processor for each received write command. Any
Modbus Function 5, 15, or 16 commands will be passed from the port to the
processor using this block identification number. Ladder logic must handle the
receipt of all Modbus write functions to the processor and to respond as expected
to commands issued by the remote Modbus Master device. The format of the
formatted pass-through control block is shown in the following tables:
Function 5
Offset Description Length
100 9958 1
101 Number if word registers in Modbus data set 1
102 Starting Address fro Modbus data set 1
103 to 366 Modbus data set 264
The ladder logic will be responsible for parsing and copying the received
message and performing the proper control operation as expected by the master
device. The processor must then respond to the pass-through control block with
a write block with the following format.
Offset Description Length
100 Place a zero in this word after the SLC has processed the pass-
through message block 1
This will inform the module that the command has been processed and can be
cleared from the pass-through queue.
Function 6 and 16
Offset Description Length
100 9956 1
101 Number if word registers in Modbus data set 1
102 Starting Address fro Modbus data set 1
103 to 366 Modbus data set 264