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Control
To tare the device, ground pin 4 (analog in) of the DB9 connector. This feature is only
available on the IM meter (not the IMC controller). When the connection is closed, the
device tares. Operation resumes when the connection is opened.
Taring flow should only be done in a true zero-flow condition. Taring pressure should be
done when the device is open to the atmosphere.
Note:
Performing a tare interrupts any current measurements.
Changing the Setpoint
Manage the setpoint using the analog Input signal (Pin 4 of the DB9 connector). The voltage
sent to the controller is proportional to the full range of the device. For example, to set
the setpoint to the maximum value for a controller with an input of 0-5 Vdc, apply 5 volts.
To set it at half of the full-scale range, use 2.5 Vdc.
Reading the Flow
The analog output signal (Pin 6 of the DB9 connector) is linear over its entire range. For
ranges that start at 0 Vdc, a no-flow condition is output at approximately 0.010 Vdc. The
full scale of the device is output by the top of the range: 5 Vdc for 0–5 Vdc, 10 Vdc for 0-10
Vdc, or 20 mA for 4–20 mA signals.
Some devices have an optional 4–20 mA current output signal, which requires 290 mA
power.
!
Warning:
Do not connect 4–20 mA devices to “loop-powered” systems, as this damages
portions of the circuitry beyond repair and voids the warranty. If the device must work
with existing loop-powered systems, use a signal isolator and a separate power supply.
Valve Overrides
To force the valve to remain closed, ground Pin 1.
To force the valve to remain open, ground Pin 2.
Only one of the two pins should be grounded at a time.
Alarm Output Option
Some devices include an optional alarm output (5VDC, 12VDC, 24VDC) that can output a
signal on Pin 9 when certain parameters are reached. The voltage of the alarm is determined
at the time of production. For more information on configuring the alarm output, see the
alarm tutorial at
alicat.com/using-your-alicat/alarm-function-ale-command-tutorial/
