Replace analog amp meter with digital

[sparkzilla]

I am trying to replace the analog volt and amp meters on an older KEPCO ATE 55-5M Linear power supply (0-55VDC, 0-5A). I purhcased 2 panel meters from lightobject. One EPM-8145B200V for volt and one EPM-8145B2V that I was hoping to use for amp. I also purchased a PS1205-2W DC-DC power module for isolated power to the meters. The volt meter is in place and works great. The 2V 8145 meter will not work for the amp meter. Whenever the digital meter is connected in place of the analog amp meter, it shuts down the PS (power supply) because the added resistance from the digi meter errors the cont circuit. I can connect the 200V digi meter in place of the analog map meter and the PS is ok. I didn't realize it before I purchased this meter but the amp meter is connected directly to the PS shunt. Makes perfect sence of course but at first glance I thought the meter was driven off the control circuit board. The sensor wires from the shunt go to the control board and the meter connects to the control board. Closer inspection revealed they are directly connected together without any circuitry inbetween. I would have purchaces a current meter if I had of known.

So I finally get to my question: Is there a way to make the EPM-8145B2V meter work to replace the analog amp meter? The voltage from the factory shunt is 0-500mv. 100mv = 1A on the factory analog meter. I can't replace the factory shunt because the control circuitry is designed to use it.

Extra info: Setting the PS to a voltage of less than 2V and then connecting the EPM-8145B2V in place of the factory analog volt meter also shuts down the PS. Seems it's just too low of a resistance for the PS control circuit. An OHM meter reads 109K across the EPM-8145B2V input connectors and somewhere up in the megaohms on the EPM-8145B200V meter.

Thanks for any assistance you can provide.
Sparks

[Tech_Marco]

Just buy a 8145 type 20A Amp meter instead. I don't understand why would you use a 2V Volt meter to work as an amp meter. What you need an extra is a 20A, 75mV DC shunt and a 5V isolated power module for the amp meter. See Manual section to review the connection of amp meter with an isolated power module

M

[sparkzilla]

Thank you for your reply. I didn't think you would be able to help but it was worth a try. Like I said in the first post. I got the 2v meter by mistake because I thought the signal for the amp meter was being conditioned by the control board and also the factory shunt is a 100mv type and all you sell is 75mv units. I don't want to add an additional shunt in-line just for the digi meter. If the 2v meter I purchased from here didn't have such a very low impedence, it would work.

Thank you again for the quick response.