Keith,
Whatever the link you go for you need to deal with the possibility that it will be intermittent or just fail. This involves knowing when it fails and having a course of action to deal with it.
You can use hardware fault status info or heartbeat strategies to know when it fails. A PLC...
Keith,
Danw2 is correct with his advice. The distance of 15 miles is a long way for unlicensed radios at 1W transmit power. Any trees, hills, dust storms, rain, fog and you might have some trouble getting a reliable link.
If you get a phone line you might be able to go for VPN solution or at...
Thanks Slava for following through with this.
Given that your suggestions are focussed on cable and earthing arrangements, is this communication lockup something you have experienced before due to incorrect cabling arrangements?
In my experience incorrect cabling has caused either no...
Thanks for your responses.
It is interesting that other ABB relays have communication issues as well. I did like the thought of the firmware upgrade but it sounds as though it is not possible.
Baud Rate is 9600. Shield is continuous and earthed at Prosoft card end only. Terminating...
We are having a problem with the loss of modbus communications between ABB protection relays and our ControLogix PLC.
We have several (approx 25) 11kV and 3.3kV switchboards comprising ABB protection relays (approx 120 x REF610, 15 x RET541, 15 x REX521). The relays communicate via Modbus RTU...
Your last couple of posts electricpete make it clear that you are not dealing with connected load issues. In fact if you could decouple the pump you may end up with the same trips.
Circuit breaker sensitivities extend to harmonics and higher ambients also. I suspect that the higher ambients...
Just had a thought.
Is it possible that you have a intermittent phase to phase short. It may not show up if you have done an insulation test phase to earth or low voltage motor winding tests. Possibilities include MCC and cable. Burn marks would be expected also if due to surface tracking...
Spot on Blackcountryman. That is my understanding.
The need for positively guided interlocking often suggests the need for safety rated relays using dual channels with test and reset functions. This is a specialist area and is covered by BS 5304 Code of practice for safety of machinery. In...
Can't say I am convinced with this suggestion even before I start as an instanataneous trip normally points to an electrical issue. However...
Commissioning centrifugal pumps for the first time is often the most arduous starting duty that the pump will see due to the need to fill the pipe...
I haven't got my RSLogix in front of me at the moment so I'll try and rememeber some of the settings that I normally use. I generally follow a Ziegler Nichols type approach.
1. Equation Type - Dependent Variables
2. Start with K' = 0.5, I' = 1000, D = 0
3. Increse K until oscillations are seen...
Continuing on the theme of inertia, if you try to slow the motor down too quick it can lead to VFD trip due to overvoltage on the DC link.
I agree, contacting the VFD manufacturer is the way to go but they do need some specific info on the load that you are trying to pull up. It is not a...
