Ground detection device to break circuit

[ckramer]

I'm looking for a power input module or relay type device to break power supplied to our machine if no ground is detected. Would a GFIC wired inside the machine help in this situation?

We've recently been suppling machines to China and the Pacific Rim and have had issues with RS-232 communications due to no ground or circuits with high ground potential. Looking for something rated at 10A 120/230VAC.

Thanks,

Chad

 

[ykee]

Quick Question: Is the communications ground somehow bonded to the machine?

 

[ckramer]

Yes, this really relates to the HMI powered by 24VDC supply. It communicates via RS-232 to a PLC. In addition to the 24/0VDC power input terminals it has a ground terminal, if this side is not wired to the machine we get abnormal communication results.

 

[itsmoked]

Just find the correct optically isolated RS-232 module. Do not attempt your original solution.

A device like:

http://www.l-com.com/productfamily.aspx?id=827

Keith Cress
kcress -

http://www.flaminsystems.com

 

[ckramer]

That would be a good solution, unfortunately I was asked to find something specifically related to the power entry. This situation could apply to some of our other machine lines as well, one of them relies heavily on analog signals and also requires a solid ground reference.

 

[alehman]

I agree with Keith. Your communication should be isolated even if you have ground detection.

There are devices such as the following that will detect ground continuity. I'm not sure how they work or if it could be integrated in a tool.

http://www.terrauniversal.com/products/desiccators/groundwatch.php

 

[CoryA]

An SE-525 Earth-Leakage and Ground-Integrity Monitor may work here...

SE-525 Earth-Leakage and Ground-Integrity Monitor

A PDF version of the manual is available here.

Are 8-A output contacts sufficient?

---
Cory Anderson

http://startco.ca/