QTech Data Systems Multi Point Controller (MPC) System - Manual (Page 5)

QTech Multi Point Controller for WP2P - Quick Start Guide – v1 – August 2012 5
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The Number of Retries setting specifies the number of times that the Controller will
transmit a poll to a given WP2P module before determining that communications with
that module has failed. For each communications attempt, the Controller will wait for
the Retry Timeout before re-attempting. Once the specified number of retries has
been reached the Controller will determine that it cannot communicate with that
particular WP2P module, and will move on to the next WP2P module in the
sequence.
Example – We have a Multi Point system with three WP2P modules.
The default settings are:
Poll Period: 5000ms, Retry Timeout: 200ms, Number of Retries: 3.
Every 5000ms (5s) the controller will poll each of the WP2P modules in sequence.
The WP2P modules have to provide a reply within 200ms of being polled. If a reply
from a specific WP2P module is not received within 200ms, the Controller will attempt
another 2 times each separated by 200ms. If the WP2P module does not reply the
Controller will move on to the next WP2P module and flash the “ERR” LED to
indicate which WP2P module.
The absolute minimum poll period is 2 seconds but we recommend 5 seconds to
cater for worst case conditions.
Note – The red “ERR” status LED on the Controller will flash to indicate a
communications error. The number of flashes represents which WP2P module
the Controller couldn’t communicate with. eg if ERR flashes two times, the
communications to WP2P module 2 has failed.
I/O Link Editor.
The Link Editor is a versatile and powerful way of setting what I/O does what and
where in the system.
Simply click in each box in the I/O grid to define the system I/O mapping.
The yellow shading is provided to help navigate between modules and has no effect
on functionality.
Note – For ease of use please maximise this window on your PC. This will
allow you to view and manage seven WP2P devices on a 1280x1024 screen
without scrolling.