Purpose Behind driving rods at equipment locations

[zbang]

RS232 is quite limited when directly connected. However, with our isolators we can operate at 115.2 kbaud out to 4000 ft. .

If you put a line driver at the near end and a receiver at the far end, what runs between them is highly unlikely to be RS-232. Yes, it's a serial line, but it's probably not RS-232. "Real RS-232" can't drive that much cable at any decent speed. (Omitting discussion about driver source impedance, voltage swing, slew rates, etc.) Tried it, didn't work, bought the line drivers.

 

[quogueelectric]

More ground rods in paralell creates a lower total ground ohmic resistance therefore BETTER ground not perfect ground. More is better. When untrained individuals tie grounded wires with ground wires all over the place this is where the trouble starts.

 

[K8MHZ]

I worked in a shop where there were some CNC and PLC issues. Mr. Brilliant Engineer said we needed to sink ground rods at all the machines. Drilling through the 6 to 8 inch concrete floor and then pounding ground rods into beach sand confused me a bit, but I did as I was told. I got pretty good at it, too. Hilti is my friend!

Sinking a hundred or so rods helped considerably as I did it on overtime after my shift and made pretty good money doing so. I don't recall them being effective, however, as I spent a great deal of time locating and mitigating signal line noise in the plant afterward.

Let's put it this way....no amount of grounding rods is going to get rid of noise caused from line side induction into signal side lines due to poor design and or installation. There was hundreds of feet of improperly installed conduit with signal lines tied to them, using the conduit for support. Duh.....

Shields were not connected properly and the wrong cable was used in some places. Min. radius was compromised by knots in the cables in some places.

Shields were often damaged as this was a die cast foundry and lots of stuff caught fire there and people drove lift trucks like bumper cars.

Ground rods in beach sand accomplish very little, especially in the form of EMI abatement.

In this case, especially. The machines were lag bolted to the concrete which provided an order of magnitude increase of ground contact compared to a 5/8 inch 10 foot long ground rod.