There are a lot of applications of PLC that need a Remote correlation, from register data adjustment, Monitoring data, and SCADA control to PLC programming. All of these applications need a consistent link in an industrial conditions multiplicity. Westermo modems offer a reliable connection for these cruel industrial connections, which can store an Engineer an expensive trip to location or provide a communications connection to a hazardous field. This Application Note gives detailed information on relating Westermo Modems and the PLC’s brand of Modicon offered by Schneider Electric. The PLC’s brand of Modicon uses the Modbus protocol as defaulting on the ports of serial programming.
The settings default for the complete Modicon Compact, 984 Series, Quantum and Momentum range of PLCs, 8 Data bits , 9600, 1 Stop bit and Even parity using the Modbus Protocol because of the different packages of the software existing for the Modbus based PLC’s, each having a different setup of communication, HyperTerminal has been utilized for this application note. The dial up of Modem connection is created using Windows Hyperterminal and next Hyperterminal is closed and after that the Programming package is utilized to link to the PLCs. When the programming has been finished then Hyperterminal is restarted and the Modem link is terminated.
This application note is depend on the default sets of the Modbus based PLC’s. The 9600,8,E,1 settings are used as memory settings standard for all of the PLC’s listed. The Compact, Quantum and 984 Series also have a RTU or DEF switch setting that powers the port to be 9600,8,E,1 if the settings have been updated in memory. When using the RTU or DEF switch the address of PLC is taken from the settings of switch on the PLC that are also utilized for the PLC’s Modbus + address. Proworx NXT does have a setting modem that forces the communication port settings at the PC end to 9600,8,N,1.