Connect a single quadrature encoder to more than one input device

[Aure_PLCs]

Hello, friends,

I am trying to upgrade a system that uses an Onrom incremental encoder (E6B2-CWZ6C) connected to a Danfoss VFD (FC360), but now the same encoder signals need to be sent for high speed inputs on a CLP S7-1214. The encoder outputs (A/B) are open collector type, it seems that there would be no problems connecting the inputs in parallel, but I am not sure.

Has anyone on the forum already had a similar problem?

Best Regards,

 

[Steve Bailey]

There will be a limit to the number of devices, but that limit is quite likely greater than two. The encoder specs may give you the maximum current for the encoder, but getting the current draw for the Danfoss and the PLC inputs may not be as easy.
The only time I had to do it, I managed to connect one encoder to three PLC high speed counter modules.

 

[robertmee]

They ain't cheap, but I've always used an Encoder Splitter, like the Dynapar.

 

[BryanG]

So long as both devices share a common (minus or 0V) then you should be fine, I share an encoder between two PLCs. If they don't share a common you can get an Encoder Splitter as robert suggested, or you can use opto-isolators to do the same job.

 

[Aure_PLCs]

Hi friends,

Last weekend they let me do a test when the line was out of product. I connected the A/B/GND signals of the VFD input in parallel with the PLC inputs and it worked fine during the test. But this was just a test of concept, which some limitations.

At first, the idea of using an encoder splitter seemed good to me, but while doing the field test I discovered that the VFD has an RS485 port available, I'm going to investigate what protocols it supports.

Your ideas were very helpful. Thank you.