Problem with Omron cmp2a and tc35i Gsm modem

[cmp2a !@#$%^&*@]

Hello all,
Im currently working on a project that involves the use of an Omron plc an a Siemens Tc35i gsm modem. So far i have set up the
plc to send SMS messages wihout a problem to my mobile. .... But if i send a SMS text to the plc/modem the 1st to 3rd characters are sometime missing when i look in the DM area. Ive exhausted all ideas. I need the full SMS message to be displayed correctly so i can use a compare function to switch on/off various outputs. Please somebody help me resolve this. Thanks

 

[cmp2a !@#$%^&*@]

Forgot to mention the plc is an omron cmp2a

 

[gtsuport]

Welcome to the forum.

How is your RXD instruction set up?

What enables the RXD?

 

[cmp2a !@#$%^&*@]

Hello and thanks for the welcome,
rdx instruction is set up as follows
ar8.05------rdx(47)
Dm0000
#0000
#256

 

[cmp2a !@#$%^&*@]

i just have ar8.06 enabling the RDX function. Is this incorrect?

 

[gtsuport]

That should work properly.

One thing to try would be to change the #256
to AR09. AR09 is the reception counter.

How long is the string you are sending to the plc?

You could also try using the "@" with the RXD.
This will make sure the RXD is only executed once.
AR08.06 should only allow for one scan execution,
but it would be worth a try if you are still having
problems.

When you are not getting the correct data in the 1st
through 3rd characters, what do you get in DM0 - DM1?

Hope this will help.

 

[cmp2a !@#$%^&*@]

Hello,
I have tried changing #256 to ar9 but ar9 will not increment.The only variables that change are Dm0000 as the reception flag is ar8.06 is on. The string lenght is only 20bytes, not massive and should be manageable. What i mean by the 1st to 3rd characters missing is , lets say i send a text with just the word "HELLO" to the plc, then what i will recieve is "ELLO" , "LLO" , "LO" or "HELLO" . But the results are very random.

 

[gtsuport]

If AR09 is not incrementing, the plc is not receiving data.
AR09 is the bytes received counter.

Verify your cable.
Do you have pins 4 and 5 shorted on the Omron side?

Another thought:
Put a Normally Open contact 253.14 (Always Off) in
series with the AR08.06, and see if AR09 will increment.
If it does, then the RXD is executing when it should not.
We may need to look at the setup for the RS232 port on the
processor.

 

[cmp2a !@#$%^&*@]

Thanks,
Ill try that this minute. Funny one for you though , In the rs232 port setup area if i uncheck the box cr/lf .....Ar9 increments ,but unchecked ,well you know ....nothing.