Slave Polling Control And Status - ProSoft Technology MVI56-PNPM User Manual

Installing and Configuring the Module
The read data (ReadData) is an array set to match the value entered in the
ReadRegCnt parameter of the PNPModule object. For ease of use, this array
should be dimensioned as an even increment of 200 words. This data is paged
up to 200 words at a time from the module to the processor. The ReadData task
is responsible for placing the data received into the proper position in the read
data array. Use this data for status and control in the ladder logic of the
processor.
The write data (WriteData) is an array set to match the value entered in the
WriteRegCnt parameter of the PNPModule object. For ease of use, this array
should be dimensioned as even increments of 200 words. This data is paged up
to 200 words at a time from the processor to the module. The WriteData task is
responsible for placing the write data into the output image for transfer to the
module. This data is passed from the processor to the module for status and
control information for use in other nodes on the network. If this array is > 600
registers, change the High LIM value in ReadData rung 2 and WriteData rung 10
of the ladder file.

2.1.5 Slave Polling Control and Status

Two arrays are allocated in the module's primary object to hold the polling status
of each slave on the master ports. This status data can be used to determine
which slaves are currently active on the port, are in communication error or have
their polling suspended and disabled. Ladder logic in the processor can be
written to monitor and control the status of each slave on a master port. The
objects used are displayed in the following diagram:
Using special blocks, the processor can request the current data for the slaves.
Through the use of other blocks, the processor can enable or disable the polling
of selected slaves.
ProSoft Technology, Inc.
January 2, 2008
MVI56-PNPM ♦ ControlLogix Platform
Phantom Network Protocol Master Communication Module
Page 29 of 91