I'm working at a power plant of two Frame9E GT. There is a different in flow readings between the two units. I want to test and calibrate the flow transmitter. The device summary show that the configuration should be 4 mA for 0 kg/s (0 lms/s) and 20 mA for 10 kg/s (22 lbm/s). I don't know what is the equivalent Delta Pressure on the transmitter in order to simulate the pressure and test or trim the transmitter.
How may I know these values?
You've made no mention of the magnitude of "error" you see. It is not surprising that the meters read differing amounts, but it is a matter of amount of difference.
As a rule, TG, GT's and such are carefully prior to turn over thos the plant. It is all in the details of the meters, the piping layouts, the fuel, and the service environment...more detail than you can put in a simple question.
Usually, you can see the differential pressure created by the orifice place written on own it.
If you don't have this information, you need to take a look at the specification, there you will have the differential pressure created by your orifice plate, and then you can calibrate your device following that.
In case you have any doubts about orifice plate installation, have a look at this article: