Section 2 Installation
Operation Check Procedure: Analog I/O
a. Mount the MFC/MFM in its final orientation.
b. Apply power to the MFC/MFM and allow approximately 45 minutes for
the instrument to completely warm up and stabilize its temperature.
c. Do NOT supply gas to the MFC/MFM. Ensure that the differential pres-
sure across the MFC/MFM is zero.
d. Apply a setpoint of:
0.000 Vdc ± 10 mV (0 - 5 Vdc or 0 - 10 Vdc setpoint)
1.000 Vdc ± 10 mV (1 - 5 Vdc setpoint)
0.000 mA ± 100
µ
A (0 - 20 mA setpoint)
4.000 mA ± 100
µ
A (4 - 20 mA setpoint)
e. If the zero exceeds one of these limits, follow the re-zeroing procedure
in Section 3. The analog output signal should be:
0.000 Vdc ± 10 mV (0 - 5 Vdc or 0 - 10 Vdc output)
1.000 Vdc ± 10 mV (1 - 5 Vdc output)
0.000 mA ± 40
µ
A (0 - 20 mA output)
4.000 mA ± 40
µ
A (4 - 20 mA output)
f. Turn on the gas supply. A positive flow signal may be present due to
slight valve leak-thru (MFC only).
g. Supply a setpoint signal between:
0 to 5 Vdc (0 - 5 Vdc setpoint) or 0 to 10 Vdc (0 - 10 Vdc setpoint)
1 to 5 Vdc (1 - 5 Vdc setpoint)
0 to 20 mA (0 - 20 mA setpoint)
4 to 20 mA (4 - 20 mA setpoint)
h. Check the analog output signal. The output signal should match the
setpoint signal in accordance with the accuracy specifications provided
in Section 1-4 of this document.
i. If flow output signal does not match the setpoint, and pressure settings
are correct, this could indicate a problem with the MFC. A secondary
issue could be the gas type. When checking with a surrogate gas,
ensure that there is enough pressure to the MFC in order to flow the
correct amount of surrogate gas.
28
