Fault Finding

There are a number of reasons why an SMS may fail to be sent with the SendSMS function block or SMS COM Server:

no connection to the GSM modem
incorrectly configured communication settings of SMS COM Server
incorrect call to the ADS service
the use of an unsupported GSM modem
incorrectly configured serial terminal (Advanced or Standard, 3 byte / 5 byte, speed, ...)
incorrect telephone number
PIN required (the SIM card must not be protected by a PIN)
Serial terminal not initialised (call KL6Init)
incorrect in GSM network

A variety of tools are available to look for these errors:

Using the Log File

Keeping records in a log file can be activated with the TwinCAT SMS Server Configurator. Once this has been done, all the messages sent, and the errors are written into the TcSmsSrvCfg.xml file. The file can be found in the TwinCAT installation directory.

NT Event Log

Errors when sending messages are also always recorded in the NT Event Log. The Event Log can be opened through the TwinCAT icon on the task bar.

ADS Error Messages

If the call to an ADS Function fails, the error is coded in the function's return value. A list of these error codes can be found under ADS Return Codes.

Configuration of the Terminal

The serial terminal can be configured in different ways. Terminals that have been differently configured, have to some extent a different representation in the process image (3 byte /5 byte terminals, advanced/standard). It must be noted that the ComLib library must be appropriate for the terminal configuration. See also the documentation for the KL6xxx and the ComLib documentation:

It is also important that the terminal transmission speed be matched to that of the modem in use.

Sending a Test SMS

A test SMS can easily be sent with the Visual Basic example program, to find out whether an error lies with the ADS call or in the configuration of the SMS Server.

Sending a Test SMS using a Mobile Telephone

To find out whether the SIM card is correctly configured, it can be inserted into an ordinary mobile phone and used to send an SMS. It should not be necessary to enter a PIN number here.

Network Selection with the Westermo GS-01

GS-01 has several variations for the various networks in Europe and in the USA. The lamp on the front of the modem indicates whether a network is available. The lamp flashes if the modem is connected to a network. If the lamp is continuously illuminated, the fault finding section should be consulted in the Westermo manual.