Sierra InnovaMass 240i Series, Инструкция по эксплуатации, Страница: 77 / 115

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Navigate to the “Flow 20mA” screen in the Output (Sub Menu). Use Table 13 for guidance.
This value is the DAC value that produces 20 mA on the analog flow output. In the example
screen DAC is 56643. Press enter

and the units will begin flashing. Increasing this value will
raise the 20mA output and decreasing this value will lower the 20mA output. Use the

buttons to enter the desired numeric value, and then press the enter key

to save the
value.
Test it
You can then use the down

button to force/test “Flow 20mA” output and hit the up

button to
stop the force/test. It will flash testing until you stop the test. You can repeat this process, if
desired, until you achieve the desired result.
The engineering units are as set in the Calibration (Sub Menu). Go to that
section for more detailed information.
In the example above, assume full scale flow is 100 scfm. As a result, a 20mA output equals 100
scfm and 4 mA output equals 0.00000 scfm. These values are fixed for flow. The output is linear
between these two points, in this example, if we had a flow of 50 scfm, the output would be
12mA.
Once you have completed adjusting and testing the flow, pressure, and temperature 4-20mA DAC
values press the right key

to reach the appropriate sub-menu and use the

buttons to
enter the desired numeric value, and then press the enter key

to save the value.
Getting 4 to 20mA for Pressure and Temperature
If you have a V (flow volumetric only) or VT (flow volumetric and temperature only) unit, the P
(pressure) and/or T (temperature) low and high will be set to meter defaults to 0 to 500 psig (0 to
34.47 barg) and Temp low and high to -40
°
F to 390
°
F (-40
°
C to 200
°
C) since those are the meter
limits.
The pressure units above are the current pressure units you ordered or that you have changed in
the process pressure and temperature sub-menu.
Pressure Outputs:
In the screen below pressure units are psia then 0.00 psia would correspond to the pressure 4mA
output.
Flow 20mA
56643
Flow 20mA
56643 - Testing