pilotbabo

Hello Everyone, I have a problem that I haven't been able to solve for a long time. I have a situation where I use a GSM Modem to send reports and alarms via text messages. Everything works without problems until the PLC sends some 20 SMS messages, after which the Status Modem Busy appears permanently. The only way to get it working again is to restart the PLC and Modem. When the PLC turns on, it sends all the messages that were "stuck", and continues to work normally until the number of 20 SMS messages is reached again. Attached is a PDF with ladder of SMS subroutine and picitures of modem configuration. If anyone has an idea why this is happening, I would be very grateful for help. Best regards. SMS subroutine.pdf