I have to interface a 3300 ACM module from Power Measurement and a Modicon Quantum PLC. I have to use Modbus protocol to initiate communication from the master (PLC) to the slave (3300 ACM) using the MSTR instruction. If anyone has an example of the configuration of the MSTR block i would appreciate. The message packet is sent from the PLC through a BM85 bridge, on to a RS-232/RS-485 converter and then to the 3300 ACM module. The response of the slave is automatic but the read message packet must be set properly to give the module adress, the start register to read, the total number of registers needed and the CRC checksum code. I also want to know if this module can work with a Quantum PLC becaus the manufacturer's document says that the module emulates a 984 controller and there are some differences in adressing between the 984 and Quantum PLC. Thanks.