Apex Digital MASS FLOW METER, Руководство по эксплуатации

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14 Getting Started
Analog Signals
Primary Analog Output Signal
Most instruments include a primary analog output signal, which is linear
over its entire range. For all analog output configurations, the lowest output
indicates zero flow, and highest indicates full-scale flow. Depending on
the quality of the grounding, a zero flow condition is in the range of 0.010
Vdc. For example, a 5 Vdc output from a 0–5 Vdc 100 sccm unit would
indicate a flow of 100 sccm.
The default 8-pin mini-DIN connector places the primary analog output
on Pin 6 for voltage signals and Pin 1 for 4–20 mA current signals. Ground
for these signals is common on Pin 8.
Using Ground to Tare
You can tare your mass flow meter remotely by momentarily grounding
Pin 4, as shown below. When the switch is closed, the device will tare,
and resume operation once the switch has been released.
Option: Second Analog Output Signal
The default 8-pin mini-DIN connector places the secondary analog output
on Pin 2 for both voltage and current signals. Your device’s secondary
analog signal may differ from its primary output signal.
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See the calibration sheet that shipped with your meter to
determine which output signals were ordered.
Option: 4–20 mA Current Output Signal
If your meter has a 4–20 mA current primary or secondary output signal,
your flow meter will require 12–24 Vdc power.
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Caution: Do not connect 4–20 mA devices to “loop
powered” systems, as this will destroy portions of the
circuitry and void the warranty. If you must interface
with existing loop powered systems, always use a
signal isolator and a separate power supply.
Pin 8
Ground
Pin 4
Pin 4
Pin 8
Connect to tare