Will a digital HART controller rated at 9V at 4-20mA work on a 24 VDC control circuit?
Will a digital HART controller rated at 9V at 4-20mA work on a 24 VDC control circuit?
(OP)
I support a small test facility and we have purchased some Masoneilan control valves to replace some really old control valves. We decided to upgrade from pneumatic valve positioners to digital valve positioners. While looking through the manual another engineer found that the Masoneilan SVI II AP positioners we purchased use HART digital protocol and operate on ~9 VDC with a 4-20mA signal. The question is our control power is 24VDC so what would we need to do to make this work?





RE: Will a digital HART controller rated at 9V at 4-20mA work on a 24 VDC control circuit?
RE: Will a digital HART controller rated at 9V at 4-20mA work on a 24 VDC control circuit?
xnuke
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RE: Will a digital HART controller rated at 9V at 4-20mA work on a 24 VDC control circuit?
That actuator can 'see' 30V. You may need to play games if it is in a hazardous area and you want the lowest voltage for the barriers.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Will a digital HART controller rated at 9V at 4-20mA work on a 24 VDC control circuit?
We almost lost a 100 ft. incinerator stack due to insufficient power supply voltage.
The high, high shut-down setting was close to 100%. (Close to 20 ma.) Adding the individual device voltages indicated that we had enough voltage. However, one device in the loop was badly off spec and required several volts more than the rated voltage. As a result, the power supply was incapable of pushing 20 ma. through the loop. The maximum current possible was just below the level required to trip the shutdown circuit. We had a knock-out drum burp and give us a liquid carry-over into an incinerator intended to handle waste gas.
A stainless steel thermo-well inside the stack melted off.
Now I do a field check on my loops to prove that there are no low voltage issues.
Bill
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"Why not the best?"
Jimmy Carter
RE: Will a digital HART controller rated at 9V at 4-20mA work on a 24 VDC control circuit?
RE: Will a digital HART controller rated at 9V at 4-20mA work on a 24 VDC control circuit?