Question

We have serial comms working from a PLC that has a buffer limit of 200 characters

I couldn't see anything in the rs232 script that sets this limit

When reading SMS messages we are missing any characters send after 200 or maybe send each line as a string separately

Can we limit the module to send only 200 max. at one time?

Answer 1

There are no direct options for limiting the buffer size. Try using flow control (RTS/CTS) if your PLC supports it.

Comments

Could we remove some of the buffer characters?

The are lines of '--------------------' that, if removed, would help a lot.

Can we change these in the scripts?

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What applications you are running and what do you want to achieve exactly- to send data coming from PLC (RS232 connection) by SMS from the RUT955  to some another device? Could you provide more information about your setup and the configuration you are using ?

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We have a PLC that we have connected to the RUT955 via a serial RS232 connection. We changed the config script so that the console opens without authorisation to help with the simple PLC tools.

We have the RUT making calls and sending SMS messages

We would like to read SMS from the unit, too. The problem is that, when we use 'gsmctl -S -l all' we can receive more characters than the PLC buffers can handle so we miss any characters over 200. Reading only new messages doesnt work when using 'gsmctl -S -l new' all messages are messages have status as 'read' so the response is blank. We know we could send the command to delete any messages we have read but there is then a chance we could miss one.

We cannot use flow control with this PLC so, it would help if we could stop the RUT from sending a the characters between lines such as '---------------------------------' between each SMS

Ideally, we would like to do all of this via Ethernet but the PLC is Ethernet/IP from AllenBradley so all of this would have to be done via CIP messages which we're not sure is even possible. Have you had anybody use CIP messages to SSH or open a console with a RUT955.

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That is an interesting and creative approach. If you are reading the SMS from the console directly you could write the output of gsmctl to a file (for example "gsmctl -S -l all > /tmp/my_file") and then read the first 200 symbols- "head -c 200 /tmp/my_file". Then remove the first 200 symbols from the output and read again. There are many different ways you can achieve the same result.  To remove the "-------" characters from the output you could try something like - "gsmctl -S -l all | tr -d -".

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Thank you very much for your patience and responses

Those suggestions sound like a good solution

These commands are obviously part of the gsmctl.c program

Do you have a list of available commands so that we dont have to keep annoying you via a messageboard? :-)

Is there a document you could upload?

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No they are not part of the gsmctl, but once you pipe the output of gsmctl (with "|" symbol) then you can use many shell aplications like "awk", "sed", "tr" and others to modify the data strings to your liking. You can find examples on these online.

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thanks very much for this support

for the benefit of those that might come across this post in the future:

gsmctl -S -l all | tr -d -

^^^ works very well to delete the '-------------' line separator and reduce the character length - handy when using it with the AllenBradley ASCII cards