Andrea,
Need more info.
What are you trying to accomplish here? (ie where does this 4-20mA 'time' signal need to go ? Is the 'time' going to be displayed on a local panel?)
What type / model number of PLC do you have?
How is the existing Operator Interface currently handled?
GG
"I have not failed. I've just found 10,000 ways that won't work." Thomas Alva Edison (1847-1931)