adccommunitymod (AutomationDirect) asked a question.
4-20mA powered loops.
Created Date: August 13,2013
Created By: Bkane
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I want to install 2 ACTR050-42L-s downstream of a VFD where I have 2 fan motors. Can I power this loop directly from a johnson controls controller 15VDC output? Will I have any problems doing this? Do I have to do any special calibration steps? Thanks.
Created Date: August 13,2013
Created by: scott.lawrence
you need 12-24VDC to power the sensor, from the spec sheet literature here...
http://www.automationdirect.com/static/specs/acuampactr.pdf
so you should be able to...
Created Date: August 14,2013
Created by: Lenny Anderson
Loop powered. This means it is powered by the device's analog input loop and doesn't require an external power supply.
Created Date: August 14,2013
Created by: scott.lawrence
Loop powered. This means it is powered by the device's analog input loop and doesn't require an external power supply.
OP was asking if he could feed power to the current transducer from the Johnson Controls device....
Created Date: August 14,2013
Created by: plcnut
Loop powered does NOT mean that you don't need a power supply, it just means the device is 2 wire versus 3/4 wire.
(the specs also state 12-30 VDC P.S. so the OP should be good to go)
From the Spec sheet:
Created Date: August 14,2013
Created by: Tom Jenkins
This should be OK, but there are some cautions.
If the loop supply voltage is less than 24 VDC the burden (loop resistance) that the transmitter can handle is reduced. The spec sheet should identify the allowable load vs. voltage for the transmitter. You need to make sure that the input or display device resistance plus wire resistance is within the load limit at 15 VDC.
Make sure that there aren't any ground loops - a path to ground for the transmitter output that is lower resistance than the display or input device.
If the fans are powered by the 15 VDC (couldn't tell from your description) you may have a lot of noise on that power supply that may show up on the transmitter output.
Created Date: August 14,2013
Created by: Bob S BN
If the fans are powered by the 15 VDC (couldn't tell from your description) you may have a lot of noise on that power supply that may show up on the transmitter output.
From what I read, he has 1 VFD wired to 2 fan motors. I think he is trying to monitor the current draw on each fan with the "johnson controls controller ".
Created Date: August 14,2013
Created by: Lenny Anderson
Your correct PLC Nut, but I was thinking of instruments that had excitation voltage. Sorry if I misspoke.
Created Date: August 13,2013
Created by: Bkane
I want to install 2 ACTR050-42L-s downstream of a VFD where I have 2 fan motors. Can I power this loop directly from a johnson controls controller 15VDC output? Will I have any problems doing this? Do I have to do any special calibration steps?
Thanks.