Sending SMS messages from a GSM cell phone

To send SMS messages from your cell phone to your PLC, you must:


You can only send messages that are already part of an SMS Configuration in the PLC.


If the Limit to Authorized Phone Numbers option is selected in the SMS configuration, the cell phone number must be in the list.


Writing SMS messages in your cell phone

You write an SMS message using your cell phone keypad. Make sure that:

The figure below shows the same SMS message: as it appears on a cell phone display, and as it appears in the PLC's SMS Configuration.

When you send this message from your cell phone, the value 110 will be written into the variable in the PLC.

Sending the message to the PLC

  1. Enter the number of the PLC's GSM modem exactly as you would enter any GSM cell phone number, then send the message.

Checking that the PLC has received the SMS message

You can check if the PLC received your message by using the Acknowledge feature:

  1. Select 'Acknowledge' in Message Properties, the ACK box is checked as shown below.

  1. Use your cell phone to send the message "Holding Temperature:#110#" to the PLC.

  1. The PLC receives this SMS message; AutoAcknowledge causes the PLC to immediately return the message to your cell phone, together with the current variable value.

  2. You can now view this SMS message on your cell phone display, together with changes in the variable value.

Note that although the PLC can send SMS messages that include Numeric, Binary, and List variables, the PLC can only receive Numeric variables.

Related Topics

Using SMS Messaging

Sending an SMS from the PLC

SMS Operands

Modem Status, System Operands, and Error Messages