0-600ma converter
I have used several hydraulic proportional controls that have the electronic controller built into a din style connector cap that do exactally what you are trying to do. I have used both 12vdc and 24vdc units. Each had trimmer controls for dither, ramp, frequency, min current, max current, etc. Input on these units was 0 to +10vdc.
You could remove the controller and mount it in any container as required. I'm currently not at work and I can only think of the Wanflu brand. Calling around to vendors like Hydraulic Controls may help.
Hope this helps.
Schmitty