Fluke 725 Multifunction Process Calibrator doesn't give current output 3

[CuteQ]

I have been using it as signal injector, it worked fine giving out voltage, current and temperature output until last week, I don’t know how but I blew the fuses, I have changed the fuses. Now it gives voltage and temperature signals, but not current!!!

I set it as 4-20mA current source, but the output is zero amp when I tested it with my voltmeter. When I connected the signal injector into the socket for pressure transmitters, it keeps flashing “OL” on the device, and the controller on the front panel is not giving out any reading, I know for a matter of fact that the loop is fine, because I tested the loop before the Fluke device starting playing up.

I don’t know what’s wrong, it’s really frustrating, please help.
Thanks

 

[catserveng]

I had a similar problem about 2 years ago with my 725, it had to go back to the factory. It was returned repaired at no charge.

I'd call Fluke, their service people have always been helpful to me, they may know what the issue is and usually they are pretty good about helping you get your tool back in service.

Hope that helps,

Mike L.

 

[KiwiMace]

Current sources probably will show zero amps connected to a voltmeter - I assume you mean multi/am-meter? The mA has always been a separate fuse in Fluke gear, although not sure on this item, make sure you found all the fuses.

 

[CuteQ]

Thank you for the replies.

Yes, it was a multi-meter, I set it to read current, and in fact I did get readings on the multi-meter later on. There are two fuses in the device that I could find, I changed both of them.

When I connected Fluke in my loop, the 24V power supply was connected too, could that be the reason why it flashes "OL" on my Fluke? Is there an option to change Fluke to use internal or external power supply?

Thanks

Michelle

 

[ScottyUK]

Yeah, the 725 can either source current or measure current. If it is trying to source current into an open circuit or into a more powerful external source then it will either indicate O/L or blow a fuse.

The instrument can be set to either source current or measure - I think measuring current uses the right pair of terminals, and source uses the left pair. Check the manual - it's on Fluke's website.


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If we learn from our mistakes I'm getting a great education!

 

[CuteQ]

"If it is trying to source current into an open circuit or into a more powerful external source then it will either indicate O/L or blow a fuse." -- Do I have to remove my 24v power supply? But if I disconnect the 24v, the loop will be an open loop...

I'm using it as current source (left two red terminals).

Thanks

 

[KiwiMace]

Sounds like you found your problem. A handheld current source is self-powered - not a regulator of the current in otherwise powered loop. Thus it has issues with any competition.

Replace the power supply and transmitter with the device to test the whole loop, or more typically you drive the controller or valve independently and you don't run into these sorts of problems.

 

[catserveng]

The 725 has a simulate mode that lets you simulate a 4-20mA transmitter using the installed loop power supply.

I use the function regularly with no problems, look at page 29 of the manual and make sure you are setup properly.

From the manual, the next page in the manual has a graphic showing proper install.

Simulate is a special mode of operation in which the
calibrator is connected into a loop in place of a
transmitter and supplies a known, settable test current.
Proceed as follows:
1. Connect the 24 V loop power source as shown in
Figure 14.
2. If necessary, press
for SOURCE mode.
3. Press  until both mA and SIM display.
4. Enter the desired current by pressing  and 
keys.

 

[CuteQ]

Thanks!