4-20ma signal output based on 12 hour clock

[Bandit DFW]

I am trying to come up with a circuit that will give out a 4-20 ma signal based on time. The output would be 4ma 12:01 with a linear progression to 12ma at 6:00 and 20ma at 12:00. Has anyone seen a circuit that would do this?

 

[kellys_eye]

Given the 4-20mA interface usually requires some form of input signal - and that can be 'any' type of signal - it's surely only a means of scaling the input accordingly?

A stepped ramp with 720 steps (call it 1024 but resetting at 720) could be built feeding an R2R ladder and used as the input perhaps?

 

[dorke]

Welcome to EP.

A uController with a 24 hour timer and a D/A could do the trick.
It will be an all software project.
There may be a need to convert the output voltage to current,