Event Command Blocks (1000 To 1255, 2000 To 2255) - ProSoft Technology CompactLogix MVI69E-MBS User Manual

MVI69E-MBS ♦ CompactLogix™ Platform
Modbus Serial Enhanced Communication Module

8.4.1 Event Command Blocks (1000 to 1255, 2000 to 2255)

Blocks 1000 to 1255: Event Port 1
Blocks 2000 to 2255: Event Port 2
Event Command blocks send Modbus commands directly from the ladder logic to one of
the Master ports. The Event Command is added to the high-priority queue and interrupts
normal polling so that this special command can be sent as soon as possible.
Note: Overusing Event Commands may substantially slow or totally disrupt normal polling. Use Event
Commands sparingly. Event Commands are meant to be used as one-shot commands triggered by special
circumstances or uncommon events.
Blocks 1000 to 1255 or 2000 to 2255: Request from Processor to Module
Description
Offset
Write Block ID: 1000 to 1255 for a Port 1 command or 2000 to 2255 for a Port 2
0
command. The last 3 digits of the command specify the slave address to use for the
command.
Internal address in the module to be used with the command.
1
Count parameter that determines the number of digital points or registers to associate
2
with the command.
Swap type for the data.
3
Modbus Function Code to be associated with the command.
4
Modbus address in the slave device to be used in the command.
5
Spare
6 to (n-1)
Where n = 60, 120, or 240 depending on the Block Transfer Size parameter.
Blocks 1000 to 1255 or 2000 to 2255: Response from Module to Processor
Description
Offset
Read Block ID: 1000 to 1255 or 2000 to 2255 requested by the processor.
0
Write Block ID: To be used by the processor in its next Write block
1
Result of the event request. 1 = the command was placed in the command queue; 0 =
2
no room was found in the command queue.
Number of commands in the command queue for the specified port.
3
Spare
4 to (n-1)
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Reference
User Manual
Page 133 of 159