Modbus protocol with the Ace PLCs on RS232, RS485 and USB Ports

Rs232/485 serial ports can be configured by vBuilder for either Modbus RTU slave (USB port also) or Custom communications operation. Each port can also the configured for a variety of baud rates, the number of stop bits and parity. Serial ports that can be configured for either RS232 or RS485 have another configuration selection for that purpose.

All serial ports and USB port support Modbus RTU protocol The PLCs are slave devices. The default device address is 1, but can be configured to any desired address via vBuilder.

Modbus communications is autonomous and simply requires set up of address mapping, using vBuilder, as shown on the right. Once set up and connected, communications occurs automatically.


When configured for Custom communications, the port will send and receive character (ui8) arrays, under program control, through the use of program blocks like those shown on the right.

Find this information in the Ace User Guide