Trio E/M and Q Radios.

[Anonymous user]

current configuration is as follow.

Base Station Radio is E-series Er450 and Remote side radio is M-series.

Now i have a requirement to use the Port-B of E-series because i have an additional system other then the existing Scada System.

As M-series radio has only 1 port so i have to change the radio at remote site which have 2 ports. so i selected Q series Radios which have 2 ports. Now there are 2 different masters connected to each port of E- series Radio polling their respective slaves at each remote sites connected to each port of Q series radios. But i am facing data loss on one of the port.

I have tried Collision Avoidance techniques still i am facing data loss on one of the port.

I am looking to the solution how could i manage to minimize the loss of data.

[Joel_Weder]

Hello  @Anonymous user,

 First, I should say that if you are looking for help getting your radios working right away, this is really not the best place to ask your questions. Instead you can contact our Technical Support team:
SupportTRSS@se.com or
1-888-226-6876

I can respond generally though. Certainly, the Trio QR450 radio can replace Trio ER450 (two serial ports) or ER45e (one serial, one ethernet) radios, when configured for the E/M Compatibility mode. As you're trying to set up two serial ports you would need to configure both serial ports of the radio, after it's been changed to E/M Compatibility mode.

You must ensure that the Port stream ID's match at both ends of the link, and that they are different between the two ports. For example, Port A could use SID 3 for both Rx and Tx, and Port B can use SID 5 for both Rx and Tx.

If you use different SID's for Rx and Tx, they must be reversed at the distant radios. Different Rx/Tx SID's is not necessary except for unusual cases, but if you are doing that, typically it would be something like:

Port A      Master Radio: Rx = 3, Tx = 4     Remote radios: Rx = 4, Tx = 3

Port B      Master Radio: Rx = 5, Tx = 6     Remote radios: Rx = 6, Tx = 5

Typically Carrier Detect collision avoidance mode does a pretty good job to minimize collisions. Ensure that is enabled in all radios. Also, the E Series radios (or Q series acting as E Series) has a transmit data buffer for each serial port, and will only allow one port to access the radio channel at a time. However, if two remote device at different sites both decide to transmit at the same time there is not much that Carrier Detect collision avoidance can do about that. (especially if those two sites cannot hear each other)

Also, of course, the serial port settings must match in the radio and devices connected to each port of the radio. And the serial cables should be standard 3-wire straight-through type.

Again, I do suggest you contact our Tech Support team for any further assistance with this issue.

[Anonymous user]

Dear @Joel_Weder ,

First I would like to thank you for your generous reply.

Secondly I was in contact with the support guy regarding this issue but from last couple of week I didn't hear from him despite sending reminder again and again that's y I came to this platform.

My current settings are as below.

Base station radio is ER450.

Both ports enabled port A is standard modbus port.

Port b is customized as per our requirements.

Character layer is custom settings 38400, N, 8,1

Packet layer is custom settings maximum bytes 2500, minimum bytes 11.

SIDs are different for TX and RX same as mentioned you.

Remote site radios are Q series configured as E modulation with above same port configurations.

Collision avoidance applied as carrier detector at both ends.

[Joel_Weder · Accepted solution]

Hello @Anonymous user 

I have sent a note to our Tech Support team asking for them to reach out to you. Hopefully tomorrow morning they can do so.

One item that stands out in the list of configuration items you mentioned is the Maximum Packet Size. The packet size of 2500 is VERY LARGE, and could cause problems. Sending a packet this size at a radio data rate of 9600 bps would take almost 3 seconds. It is quite possible that a burst of noise or interference could cause the message to be lost.

While it might be possible to configure the Maximum Frame size to 2000 bytes, it is certainly not advisable. These messages would be much more likely to succeed if they were perhaps somewhere in the range of 200-500 bytes or so. 

After you have made that change, I suggest you test the communication again. If still not working, SAVE configuration files for the Master radio and the remote radios that are experiencing the problem, and send them to the Tech Support address given earlier. Also, in the same email please describe your Custom protocol as clearly as you can. It is a bit unusual for a serial SCADA protocol to send messages that 2000 bytes long.