What could the reason micrologic unit 6.0A not displaying properly?
If you have a 24VDC, the screen must display something.
if you don't have a 24VDC, the screen will display only when the load will be from 20% of the Ir (but in your case you do have the 24VDC supply).
You can connect a FFTK (Full Function Test Kit) to display the screen.
If the display doesn't light anything with FFTK or 24VDC, it means it is a quality issue on the Micrologic and it needs to be replaced.