MKS MF1 - Chapter 5 Process Interfaces; Functions; Report Functions; Valve Override

Chapter 5: Process Interfaces
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Chapter 5 Process Interfaces
Functions
Beside the normal flow control mode the units are equipped with digital interfaces, which provide a
number of helpful functions and useful information.
Report Functions
Calibration Date, Type, Model, Manufacturer, Serial No., Firmware/Hardware Revision, Product
Code, Date of Factory Calibration, Full Scale Range, Flow Unit, Standard Temperature Standard
Pressure, Valve Type, Valve Power Off Mode.
Valve Override
With the override signal the control valve can be driven completely open or closed.
Set the parameter VALVE_OVERRIDE to NORMAL to allow the mass flow controller establishing a
flow in accordance to the setpoint command FLOW_SETPOINT.
Set the parameter VALVE_OVERRIDE to FLOW_OFF to completely close the control valve.
Set the parameter VALVE_OVERRIDE to PURGE to completely open the control valve. This
command may be used to purge or vent the instrument or the system.
Auto Zero
If VALVE_OVERRIDE is equal to FLOW_OFF and THERMAL_MASS_FLOW_RATE is smaller
than 5 % of full scale, the flag AUTOZERO (0 to 1 transition) will take the actual sensor signal as
zero and will subtract this value from all future measurements (refer also to USER_ZERO).
Note: Zero adjust can be performed also using the AUTOZERO button (See also page 24).
Alarm Limits
LOW_TRIP_POINT and HIGH_TRIP_POINT define the limits for LOW_LIMIT_ALARM and
HIGH_LIMIT_ALARM flags. Consider that there is a 0.5% hysteresis for each limit switch. The
hysteresis of 0.5% is divided in a slope 0.25% above and another slope 0.25% below the defined
limit.
Temperature Measurement
The internal temperature of the device is measured in °Celsius and given as INTERNAL_TEMP.