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PLC09 Order Form


The PLC09 Arbitrator unit (MODBUS port expander or multiplexer) permits communication to a PLC or other MODBUS device from a single serial port to up to three separate host computers or terminals.


PLC09 access is granted to the first host to communicate and is released upon expiry of an adjustable timeout. A request received while the PLC port is active is buffered until the current message is complete. The unit can also convert ASCII to RTU protocol.


Command Buffering Messages may be buffered in the arbitrator until the entire message is complete before transmission to the PLC. This is beneficial when the host introduces a variable delay between characters which cannot be tolerated by some PLCs. Variable Baud Rates Separate independent baud rates are supported on the four serial ports (three host, one PLC). Baud Rates - 110, 300, 600, 1200, 2400, 4800, 9600, and 19200. Configurable thru Host 1 port. ASCII and RTU protocols can be intermixed on the three host ports. (Configuration software is included) LED activity indicator. RTS control on Host 1 and PLC ports for half duplex operation or for server type devices which cannot control RTS.


Enclosure is 5" by 7" by 1.5" molded plastic Host 1 - 9 pin female D connector Host 2 - 9 pin female D connector Host 3 - 6 pin female RJ12 connector. PLC - 9 pin male D connector


Wall plug power supply. Input 120 VAC, output 9 VDC @ 500 m.a. 12 VDC standard, 24 VDC optional (100 m.a. required) -20 to + 75 degree C operation FCC Class A compliance

Protocols Supported:

MODBUS (RTU and ASCII) Call for information on other protocols


One year parts and labour on a factory return basis

Ordering Information:

PLC09 model, MODBUS interface

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