R
Hi Group,
I just came across something new with the HART communication on field instruments. We are equipped with Bailey Infi 90 dcs with almost 8 nodes. (Say PCU 1 TO 8) Recently the transmitters connected to PCU6 stopped communicating with HART when connected across TRANSMITTER'S POSITIVE and NEGATIVE terminals. Checked for the loop resistance, grounding, restarted the power supply module etc and found normal.
We continued trouble shooting with reference to loops from other PCUs.
The result is:
HART comm is success when connected to transmitter terminals from (Both on transmitter and cabinet side) for all PCUs except PCU6.
1. Positive to Negative
2. Positive to Ground
3. Negative to Ground.
- For pcu6 only Negative to Ground is able to communicate.
- My so far (mis..?!) understanding on HART signal is that it will only communicate from Positive to Negative terminals.
- This scenario is strange to me.
- Suspecting my DCS loop i tried the same testing on another stand alone ABB 800XA system in my plant and experienced the same. i.e, good communication for,
1. Positive to Negative
2. Positive to Ground
3. Negative to Ground.
My questions are;
1. Is it common that HART can communicate on above three type connections? If so how/ why?
2. What may be the reason that it couldn't communicate for PCU6 ,except Negative to Ground?
Please help.
Notes:
All that i tested were DCS loop powered transmitters. No issue with 4 wire transmitters.
Thanks,
RR..
I just came across something new with the HART communication on field instruments. We are equipped with Bailey Infi 90 dcs with almost 8 nodes. (Say PCU 1 TO 8) Recently the transmitters connected to PCU6 stopped communicating with HART when connected across TRANSMITTER'S POSITIVE and NEGATIVE terminals. Checked for the loop resistance, grounding, restarted the power supply module etc and found normal.
We continued trouble shooting with reference to loops from other PCUs.
The result is:
HART comm is success when connected to transmitter terminals from (Both on transmitter and cabinet side) for all PCUs except PCU6.
1. Positive to Negative
2. Positive to Ground
3. Negative to Ground.
- For pcu6 only Negative to Ground is able to communicate.
- My so far (mis..?!) understanding on HART signal is that it will only communicate from Positive to Negative terminals.
- This scenario is strange to me.
- Suspecting my DCS loop i tried the same testing on another stand alone ABB 800XA system in my plant and experienced the same. i.e, good communication for,
1. Positive to Negative
2. Positive to Ground
3. Negative to Ground.
My questions are;
1. Is it common that HART can communicate on above three type connections? If so how/ why?
2. What may be the reason that it couldn't communicate for PCU6 ,except Negative to Ground?
Please help.
Notes:
All that i tested were DCS loop powered transmitters. No issue with 4 wire transmitters.
Thanks,
RR..