pressure transmitter low insulation
pressure transmitter low insulation
(OP)
Hi! is there anybody who can tell me why the pressure trnasmitter connected to our ups 24 vdc showing low insulation alarm in in the UPS panel. ups is supplying 24vdc to signal acquisition unit (plc) if we disconnect all the sensors (pressure trnasmitter- p/I converter) alarm is gone but if we connect these sensors alarm coming in the ups panel which is low insulation. pls advise what are the possible remedy on this. i'm thinking that the electronics circuit made it becoming low insulation when connected to ups battery, example capacitor inside the trnasmitter circuit. is that possible? any thoughts on how to solve this problem? thanks a lot in advance. more power to all of us.
jalover
jalover





RE: pressure transmitter low insulation
Which brand/model UPS is this? I'd like to read what the manufacturer means by 'low insulation'.
What brand and model pressure transmitters?
Does the alarm occur when only one pressure transmitter is connected, or do multiple pressure transmitter need to be connected to trip the alarm?
RE: pressure transmitter low insulation
RE: pressure transmitter low insulation
When the transmitter is connected the UPS sees the 4-20 mA signal through transmitter-through PLC input to negative (ground) as a fault.
Check the PLC input negative, i am sure you will find it there.
You can probably lift the ground and allow system to float at UPS negative.
Roy
RE: pressure transmitter low insulation
Out of curiosity, are these pressure transmitters the only input devices to this PLC or are there other input devices?
I noticed that Saiernico is a marine ship builder. I am clueless about ship power systems.
Is it common to run 24Vdc as ship power? Is it convention to ground one side of shipboard DC as a common, like the negative ground on 12V automotive systems?
Could the battery bank be grounded as a common?
Dan
RE: pressure transmitter low insulation
Thank you for the prompt reply and input. I will look into this further.
RE: pressure transmitter low insulation
thanks a lot for your continous input. There's still a lot more input devices ( digital & analog) but only these 5 sensors giving an earth fault indication. disconnecting these 5 sensors will give healthy condition. I suspect these chinese made trnasmitter giving fault indication, i just wonder why happened for all. ship's power utilizing 24 vdc coming from battery bank and this is connected to a float type charging circuit, other way is by using rectifier system ( 220vac to 24 vdc) , but in our case we're using battery bank but not grounded as a common.