The problem is due the fact that you are connected to the target system by using the serial line COM0. The LogicLab is using a modbus RTU protocol over the serial line to communicate with the SlimLine CPU module. In your program you have configured the COM0 to be used with the ModbusMaster FB, so it has been detached from the operating system and now it’s impossible to communicate with it thru the COM0. There are many ways to solve the problem.
First if your CPU module has more than one serial port you can use another port instead of the COM0 to connect to it the PC that runs the LogicLab program. You can use also the COM2 in RS485 half duplex.
If your CPU module has only the COM0 you can connect to it by using the Ethernet (If the CPU module has it) or the USB cable (Using RNDIS driver). I remind that on both these cases the connection is a TCP/IP connection and you have to set the LogicLab to communicate with the Modbus TCP/IP protocol by defining the IP address of the CPU module (Default is 192.168.0.122 on Ethernet, 192.168.1.122 on RNDIS) on TCP port 502.
It’s obvious to remind that the TCP/IP conection is the best way to connect to the CPU module, thru it you can have many concurrent connections, LogicLab connected on modbus, a Telnet connection on port 23, it’s possible to transfer file with the FTP protocol, it’s possible to browse web pages with the HTTP protocol.
Anyway there is an emergency way to connect to the CPU module, by connecting the COM0 to a PC and using the Toolly program, it’s possible to activate on Tooly the CPU catch sequence. This sequence permits to capture the module during it’s power up (See the topic).
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