InTouch 9.5 and Radio Modem

B

Thread Starter

Bjorn

Hello!

I am working on a project where I use Wonderware InTouch 9.5 and SMC DASMBSerial DA server to display and log data from several PLCs over MODBUS protocol.

I have one Telemecanique TSX Premium PLC and four Koyo DL-205 PLCs.

The TSX Premium is directly connected to the computer with a serial cable (RS-232),
and the connections with the Koyo PLCs are made via Radio Modems (Satel 3AS) and serial cables (RS-232).

In the SMC configuration I have configured the different PLC locations as Modbus PLC object with the default values in the setup, except the slave addresses of course.

I use COM 1 for the TSX Premium PLC, and COM 3 for the radio modem connection.
The connection seems to work very well, but suddenly the connection to the Koyo PLCs (goes via radio modem) get unstable. When I check the Log Viewer in SMC, it says "Message: failed to verify Modbus RTU frame". The error just comes and goes. For many hours the connection works all fine, then suddenly it breaks down for a while.

The connection to the TSX Premium is doing fine all the time, so it must be something wrong with my setup of the connection who use Radio modem to access the Koyo PLCs.

Can it have something to do with the timeout and polling values? Or maybe the swap register check boxes?

If anyone has an idea how to solve my problem, I will be very happy.

Thanks in advance

Bjorn
 
Hi:

I am having a very similar issue with a radio modem. Did you find a solution for your problem?

Thanks.
 
How is your radio path? If it is marginal sometimes your signal will "fade" and you will lose contact.

Fading can be a result of a radio overheating, interference from other devices, bad weather, big objects (ships/trucks) moving in front of your path. Or it can be from bad connections or marginally faulty radios. Get a radio tech to measure the Received Signal strength at both ends of your radio. Keep the numbers in case you have future problems. (Think baseline.)

I prefer using a second PLC to poll the remote unit. Then you can read off the last poll by the master (2nd PLC). Then I would set up a watch dog program that would alarm when my communications is out longer than your comfort period.

The 2nd PLC preference was earned the hard way.
 
Hi Bjorn:
Are these MaxStream radios? I am having the same problem with my 3 remotes linked by radio.
 
What frequency and what technology is used (FHSS or DSSS, or other)?

I concur with Mr. Anonymous and his assessment of radio fade at the margin.

Here are some of the items off the top of my head for when signals fade:
- most radios have a DC voltage output for signal strength. I've left a datalogger tied to radios to see how and when the signal strength varies
- have to know signal strength when radios are operating properly
- Signal strength when radios are not operating properly
- condition of cables and connectors: water intrusion in particular.
Substitute new cable, check SSI
- condition of the antenna(s).
- cheap aluminum yagi antennas corrode in the weather and eat up the signal.
- is a directional antenna still pointing in the right direction?
- Does substituting a replacement antenna bring the SSI back up?
- antenna mounting details.
- base load has to be above reflectors on some omni models. Is it?
- where is antenna mounted in relation to obstructing reflectors
- bracket break and leave antenna at 45° polarity?
- outdoor
- water body, or temporary rain pond intruding into fresnel zone?
- tree or bush growth over time.
- multipath sources, something changed?
- fog ? snow/ice covering antennas?
- indoor environment? multipath fading? antenna diversity option?
- Is there some form of autorouting through repeaters? If so, what's the 'new' configuration vs the old topology? What possible causes for the change in routing?
- power supplies can be problematic, but I can't recall p/s affecting fade issues.

David
 
The Radiomodem I use is: SATELLINE-3AS
(http://www.satel.fi)
Frequency: 440.5mHz
Type of Emission: F1D
Communication Mode: Half-Duplex
Carrier Power of radio transmitter: 500mW.

There are pretty good sight between the antennas, who are 6 element Yagi directional with good quality. The cables and connection equipment are also in good condition.

You said something about repeater-routing. In the beginning I did not use this feature in the SATELLINE modems, but now I have to set up all the radiomodems in a feature called: MESSAGE ROUTING. And after I did that I cannot get the communication between the slaves working, using the RX command in the ladder program. Any ideas why?
 
I have got my communication working stable now.
The trouble was a wrong RX command in another slave that makes collisions.
 
Hai All,
I need technical support regarding Wonderware Intouch. How to monitor the radio communication status in Wonderware?
Actually, the receiver side of the radio generates 0-5v in Pin 5 (Analogue RSSI) depending on the communication strength. We need to show the status of the radio in Wonderware in touch. Kindly guide me.
 
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