Oil pressure alarm going off

[Mydiamond]

I have twin gas crusader 454 XL engines.
While running I had the oil pressure light and alarm come on.

I checked the oil and topped off the oil.

Ran it again, after about 20 minutes running 2800, alarm went off again.

Checked oil. Level is fine 

Low rpm’s - engine runs fine…. No alarm.

New sending unit last year (from diagnostics of another issue)

Erving up in the slip, gauge jumped from 50 to 60.

Any thoughts on next steps?

Thank you