ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
Changing a Bulb
by gfretwell. 07/14/18 03:12 PM
Tray cable?
by gfretwell. 07/11/18 10:18 PM
Eaton Heavy Duty 30A and 60A Safety Switches
by Admin. 07/11/18 09:49 PM
ORTOVOX Recalls Avalanche Transceivers
by Admin. 07/11/18 09:44 PM
Tingle off the water spigot
by gfretwell. 07/08/18 12:58 PM
New in the Gallery:
Plug terminals
Housebilding DIY wiring
Who's Online Now
0 registered members (), 7 guests, and 18 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
4-20ma Pressure Transmitter #173914
01/22/08 10:54 PM
01/22/08 10:54 PM
C
Cinner  Offline OP
Member
Joined: Dec 2004
Posts: 78
Kelowna, B.C., Canada
Does anyone have any industrial experience with pressure transmitters. My question is this: If the voltage is 10 - 30 V DC and the output is 4-20ma, would this require 4 wires to connect( 2 for the voltage and 2 for the 4-20ma output). Can the transmitter run on only 2 wires?

Work Gear for Electricians and the Trades
Re: 4-20ma Pressure Transmitter [Re: Cinner] #173915
01/22/08 11:07 PM
01/22/08 11:07 PM
B
bigrockk  Offline
Member
Joined: Jan 2003
Posts: 174
Middle of Canada
Yes it can work with only two wires. This is fairly common.

Positive transducer lead to positive of power supply. Negative of power supply to negative side of "load" . Positive side of load to negative lead on transducer.
So essentially it is just a loop.

The load could be many things such as a plc controller a meter or readout of some type etc.

Last edited by bigrockk; 01/22/08 11:15 PM. Reason: To add more info
Re: 4-20ma Pressure Transmitter [Re: bigrockk] #173952
01/23/08 03:44 PM
01/23/08 03:44 PM
N
NJwirenut  Offline
Member
Joined: Sep 2001
Posts: 806
Bergen County, NJ
4-20 mA control loops are very common in industrial control gear. In the 2-wire configuration, the transmitter is actually powered by the voltage drop across it.

A good introduction to current loop sensors here:

http://www.datel.com/data/meters/dms-an20.pdf


Re: 4-20ma Pressure Transmitter [Re: NJwirenut] #173973
01/24/08 12:06 PM
01/24/08 12:06 PM
J
JValdes  Offline
Member
Joined: Jun 2007
Posts: 301
South Carolina
How many terminals do you have on the transducer? And do you have the wiring diagram for it? Normally you will have an input 2 wires (10-30vdc) and an output 2 wires (4-20ma). Two in. Two out. No common. To test the output MA, put meter in series with one output conductor. Use the MA setting on the meter. Depending on how sensitive you need this, you may need to adjust the DC input or if provided the adjustment screw on the transducer.


Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
dougwells
dougwells
kamloops BC Canada
Posts: 1,145
Joined: May 2003
Show All Member Profiles 
Top Posters(30 Days)
Admin 5
Popular Topics(Views)
248,086 Are you busy
185,524 Re: Forum
174,814 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.019s Queries: 15 (0.004s) Memory: 0.9601 MB (Peak: 1.0930 MB) Zlib enabled. Server Time: 2018-07-16 08:23:13 UTC