Control Valve Purge Function Signals; Figure 4-4. Alarm Connection - Advanced Energy FC-77 Series User Manual

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As shown in
open collector that is isolated with the photocoupler. To use the terminals, apply
appropriate power, as shown in the illustration. Use the ALARM ON/OFF signal to
reset the signal.
Note: If no gas is being supplied, but the MFC has a nonzero set point, the MFC will
report an error (because the flow rate does not match the set point).

Figure 4-4. Alarm connection

Control Valve Purge Function Signals

The control valve purge function allows you to completely open the control valve and
purge gas at many times the MFC full-scale flow rate. This function is particularly
useful for purging gas when using MFCs with a low full-scale flow rate or for leak
checking. The settings for opening/closing the control valve vary with the connector
type and, in some cases, with whether the MFC is normally open or normally closed.
For most applications, this signal is not connected.
The following illustrations show the connection and the internal MFC wiring, for the
purge function signals on all connectors.
4-8
Figure 4-4, ALARM H and ALARM L are connection terminals for the
I/O Connections and Communication 5700512-C