MKS MKSINST IE1000A, Инструкция по эксплуатации

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Chapter Three: Operation Analog 15-pin Interface Operation
27
Note
1. The “No Connection” pin assignment refers to a pin with no internal connection.
2. The 0 to 5 V
DC
flow signal output comes from pin 2 and is referenced to pin 12 (signal
common).
3. Any appropriate 0 to 5 V
DC
input signal of less than 1K ohm source impedance referenced to
pin 11 can be used to supply a setpoint signal to pin 8.
The signal ground and power return are NOT connected within the MFC. The user should connect the signal
ground and the power return at ONLY one end of the interface cable to avoid development of ground loops.
Analog I/O Optional Input (15-pin DSUB Only)
The standard 15-pin IE500A / IE1000A High Flow Rate Mass Flow Controller can control flow based on a 0
to 5 V
DC
signal from an external sensing device using the optional feedback control input feature. (For a 0 to
10 V
DC
input range, contact the MKS Applications Department.) A common application of this feature is for
pressure control using input from a pressure transducer.
To use the optional feedback control input feature, route the 0-5 V
DC
output from the desired external device
to the optional input pin.
Voltage applied to the optional input pin overrides the signal generated by the flow sensor internal to the
MFC. The control electronics drive the valve so that the optional input signal matches the setpoint. Use the
same pin for the setpoint signal, regardless of whether you are using the optional input or the standard flow
control signal. Although the product responds to the external optional feedback control input signal, the
metered flow output signal is still provided on the standard output pin 2.
Analog IO Valve Override
The valve override feature enables the control valve to be fully opened (purged) or closed independent of the
setpoint command signal.
If the MFC is equipped with a 15-pin Type D connector:

To Open the valve, connect pin 4 to the power ground pin.

To Close the valve, connect pin 3 to the power ground pin.
Analog IO Valve Command Priority
The MFC executes commands based on a hierarchical command structure. The highest priority command is
Valve Open, followed by Valve Close, and Setpoint Control. Therefore, if the flow controller is operating
under Setpoint Control, you can send a Valve Open command to force the valve to the full open position.
Note
When both the Valve Close and Valve Open pins are pulled down, the Valve Open command
takes precedence and the valve is moved to the open position.