AB PLC-2/x <-> serial DF1 <-> Ethernet

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Thread Starter

David Jones

I am looking at an application which would use our
embedded controller board with an Allen-Bradly PLC-2/x PLC. The controller board has serial ports (RS-232/RS-485) that would communicate with the PLC via the DF-1 protocol. The controller board also has a 10 MB/s Ethernet port which will communicate with the factory LAN.

The PLC ladder logic program will have to be unique for each machine that this device is used with since different people want different data collected and monitored. Maybe the ladder logic
program would not need to modified if I can just
read the correct memory location (for monitoring
variables) and output it via the DF1 interface port.

Has anyone done something like this using the DF1 protocol using the older PLC-2/x AB PLCs? Anyone see any major issues with this application?

Thanks,
David
 
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Lynn August Linse

Just be aware that a native PLC2 won't have a DF1 port. They have a non-DF1 current loop port only - unless a rather expensive add-on card is in place with RS-232 and DF1. You probably know this already, but I just wanted to point that out for other readers.

Best Regards

Lynn August Linse, [email protected] IA Firmware Specialist, Digi Int'l (www.digi.com)
 
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Lynn Linse wrote:
> Just be aware that a native PLC2 won't have a DF1 port. They have a non-DF1 current loop port only - unless a rather expensive add-on card is in place with RS-232 and DF1. You probably know this already, but I just wanted to point that out for other readers.
>

I could add the current loop to voltage converter
to my board if I could find details on the PLC-2
implementation...

Some older posts from last year or the year before
mentioned that someone had some details on the required current loop to rs-232 adapter. Could someone point me to where I can get those or send
them to me?

If the protocol used on the PLC-2 interface port is not AB DF-1, are the protocol details available anywhere?

Thanks,
David

[email protected]
Embedded Minds Design Group
 
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Yosef Feigenbaum

Hello David,
To talk to a PLC-2 using DF1 you'll need a 1771-KG module. Regardless, I'd seriously consider finding better way to do what you're trying to do. Depending on the number of controllers that need interfacing to your network it may be cheaper to replace them.

As for the PLC2 programming port, if I remember correctly it's ttl and not current loop (forgive me if I'm mistaking) and uses 9 pins of it's 15 pin connector (8 for data + ground). If you go this route keep in mind that you'll have to disconnect your module whenever someone from you service dept. needs to look at the PLC program.

Good Luck,

(8{)} ( .)
[email protected]
 
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