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Chapter 3 Operation Series 830/840/860 Instruction Manual
3-2 IM-83/84/86-H
Mass Flow Controller Operation
Electromagnetic Valve Controllers
When the transducer is installed and the system has undergone a
complete leak check:
1. Make sure the set point is zero before applying power. If the
set point input is not connected to some type of control device,
set the valve on/off switch in the off position. (No connection
may cause the setpoint to float). Note: The valve opens mo-
mentarily when power is first applied.
2. Apply power. Allow thirty minutes of warm-up time. (When
power is first applied, the output signal from the transducer
remains fixed at a much higher than normal level until the sen-
sor warms up to its normal operating temperature range.)
3. Turn on the gas supply. Perform an initial zero output check
(only required for first-time start ups). Set flow to zero. Connect
a digital multimeter to V+out (4-20 mA out) and COM termi-
nals.
4. Check the reading. If it is not within ±50 mV (±0.16 mA) of
zero, adjust the zero potentiometer to zero the transducer. (The
zero pot is located behind the upper metal button on the side of
the transducer or behind the swing-out plastic door.)
5. Adjust the controller set point to the desired flow rate.
Caution: Never leave the controller with no gas supply while supplying a
setpoint. The valve will open to its maximum position and eventually
overheat causing possible damage to the control circuit. If it is desired
to interrupt the gas flow for an extended period, consider utilizing the
“Valve-Off” circuit.
Caution!
During operation, the
mass flow controller
valve becomes hot.