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Control
Analog Signals
Alternatively to the digital communications methods described above, the instrument can
be controlled using analog signals transmitted through the 6-pin connector.
!
Warning:
Do not supply power to the instrument until all necessary pins have been
properly connected.
Pin
Function
1
Analog Setpoint Input
2
Analog Signal Output
3
Ground
4
Power In
5
Serial RS-232 (Rx) or RS-485 B (+)
6
Serial RS-232 (Tx) or RS-485 A (-)
!
Warning:
Connecting power to pins other than Pin 4 can permanently damage the
instrument.
Changing the Setpoint
Manage the setpoint using pin 1 (analog in) of the 6-pin connector. The voltage/current sent
to the controller is proportional to the full range of the instrument. The setpoint value should
correspond linearly to 0–100% of device full scale (0–5 VDC or 4-20 mA).
Reading the Flow
The analog output signal (pin 2) is 0–5 VDC or 4-20 mA and linear over its entire range.
A zero-flow condition is indicated at approximately 0.010 VDC or 4 mA. Full scale flow is
indicated at 5.0 VDC or 20 mA. Ground for this signal is common on pin 3.
!
Warning:
Do not connect this instrument to “loop-powered” systems, as this will destroy
portions of the circuitry. If you must interface with existing loop-powered systems, always
use a signal isolator and a separate power supply.
