Can I msg between micrologix1400 and mico820

[Gavin_plc]

Hello,
Is it possible to msg write 1 bit from micrologix 1400 to micro820 over ethernet?


I'm an electricain with only knowledge of 500CPU and PLC5 messaging.

Thanks.

 

[gclshortt]

The Modbus TCP/IP protocol is supported e.g. by: Micro820, Micrologix1400.
http://www.mesta-automation.com/modbus-configuration-example-for-an-allen-bradley-micrologix-1400/
The above link will go through setting up the 1400 as a master.

Regards,

 

[Ken Roach]

Welcome to the Forum !

Is it possible to msg write 1 bit

None of the A-B controllers I am aware of support a Message instruction that transports a single BOOL value or one bit of a Data Table element.

You can use Modbus/TCP to transport an entire INT integer data element, but not just one bit.

The MicroLogix cannot natively read or write the Tags inside the Micro 820, and the Micro 820 does not emulate MicroLogix Data Table addresses, so Modbus/TCP is the protocol that these two controllers have in common.