WP2P Digital– User Guide
© 2020 QTech Data Systems Ltd
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Operation Notes
How do the modules communicate?
The WP2P modules use an event driven approach to communications. When the WP2P modules detect a change
of their input state, they will immediately transmit a message to the other module. There is however, a very
small chance that another radio device on that channel wanted to send a message at exactly the same time. This
will result in a “collision”, but the WP2P modules can detect this and use a collision avoidance scheme to
retransmit their messages.
STAT Indicator
The “STAT Indicator” indicates the current operational status of the device. It provides a heartbeat indication
that the device is operating ok or it displays a coded error indication for faults.
Faults may be latched so that the device remains indicating an error condition even if the fault has been
removed. In this way the device can be reviewed at a later time to show that a problem had occurred.
Pressing the mode switch briefly will clear the error condition indication on the STAT LED. If the fault is still
present then the STAT LED will redisplay the error condition.
Code
Meaning
1 short flash, 2s interval
Normal operating mode, Processor running, no active errors
2 short flashes, 2s interval
Unspecified intermittent communications fault. A communications failure as
occurred recently.
~4 Short flashes on power up
Indicates the device booting after power up or watchdog reset. LED should
usually then display normal operating mode indication.
Link Status Indicator
WP2P modules have a Link Status LED which is located next to the power connector.
This is to assist with site diagnostics and checking by indicating the state of the communications link between
pairs of WP2P modules.
The Link light functions as follows:
OFF – Module failure, no power, fuse blown, circuit failure, etc.
SLOW FLASH – Module functioning but no communication with its partner module.
ON – Healthy wireless communications. The LED will briefly flicker each time it receives messages from
the other WP2P module.
Link Status indicator is based on the “keep-alive” message the WP2P modules send if it has been longer than 30
seconds since they last sent a message. Therefore, if one of the modules is turned off, it will take no longer than
30 seconds for the other module to detect that the link is down and begin flashing the Link Status LED. If the
connected I/O is changing more frequently than once every 30 seconds, then they don’t need to send keep-alive
messages.
MODE Pushbutton Switch
Pressing the mode pushbutton will clear the error condition indication on the STAT LED. If the fault is still present
then the STAT LED will redisplay the error condition.
