When communication over a radio network isn't working between two ends points. there are a lot of steps in between that could be at fault. LED's on the various pieces of equipment can help to identify where the issue lies.

Let's look at an example where a SCADAPack RTU is trying to serially poll a remote SCADAPack RTU over Q radios.

Step 1: Is the main SCADAPack successfully sending out a serial message?

The SCADAPack serial port should be lighting the Tx LED for the appropriate serial port. If not, there is likely a configuration issue or error preventing the SCADAPack from sending out the message. Please verify the operation of the communication function blocks or Modbus Scanner in the SCADAPack to correct the issue. (Please note that if the main SCADAPack is only asking for data every 15 minutes, there won't be any traffic for most of that duration. It might be helpful to temporarily increase the poll frequency for troubleshooting purposes)

Step 2: Is the Trio radio receiving the serial message?

Once the SCADAPack is sending serial traffic, the Trio Q radio should flash the TxD LED to indicate it has received serial traffic to Transmit. If the Q radio COM LED is not coming on, please double check the serial wiring between the SCADAPack and the Trio Q radio.

Step 3: Is the Trio radio transmitting the message over the air?

Once the Trio Q serial port receives data, the radio Tx LED should blink red indicating that it is broadcasting the message over the air. If the Tx LED does not blink, please look at the radio configuration, focusing on the radio serial port settings.

Step 4 Is the remote Trio radio receiving the message over the air?

Once the main Trio Q radio has transmitted, it's up to the remote radio to receive the message, indicated by a green Sync LED. If the remote radio shows a red RxSig LED, the radio modem could be getting a weak or undecodable message. Verify the radio-to-radio configurations and antenna setup to ensure the radios can talk to each other.

Step 5 Is the remote Trio radio sending the message out the serial port?

If the COM port RxD LED does not blink, then the radio may not be handling the over-the-air data properly. Please look at the radio configuration, focusing on the radio serial port settings.

Step 6: Is the remote radio receiving the message on the serial port?

Once the Trio radio is sending data, monitor the remote SCADAPack serial port to see if it receiving data. The Rx LED should blink to indicate traffic. Please double check the serial wiring if the signal is not making it to the SCADAPack.

At this point, the remote SCADAPack should take the message and send a reply back. If the SCADAPack does not send a reply, please verify the station is addressed properly and that serial port settings (baud rate, parity, etc..) match between the SCADAPack and Trio Q radio.

Once the remote SCADAPack is able to send a reply, repeat steps 2 to 5 for the reply back to the main SCADAPack to ensure the response makes it back.

Released for: Schneider Electric Indonesia