Experimental Physics and
Industrial Control System

"Hartman, Steven M." <[email protected]> · Fri, 13 Sep 2013 16:35:02 -0400

On Sep 13, 2013, at 9:27 AM, Rod Nussbaumer <[email protected]> wrote:
> 
> Has anyone used any other alternative system to achieve greater load 
> current stability? There is a concern about the ability to tightly 
> control load current at very low currents. Does this or any other system 
> impact that capability?

Hi Rod--

What are your stability requirements? Are you more sensitive to AC related noise or DC drift? Absolute accuracy or relative stability? At low currents, is the concern for discontinuities at zero crossing for bipolar supplies?

I have implemented slow feedback at the EPICS level for DC drift of power supplies which worked adequately for that use case (long time scales). But for AC related noise, you likely need to do that at the controller hardware level. In a previous lab, we used an external DCCT for regulating undulator power supplies (few e-6 stability requirement) using the output from the DCCT in the controller's feedback circuit. 

-- 
Steven Hartman
[email protected]

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System