Alicat V Series Volumetric Flow Meter - Manual (Page 9)

7
RS-232 Digital Output Signal
If you will be using the RS-232 output signal, it is necessary to connect the RS-232 Output Signal
(Pin 5), the RS-232 Input Signal (Pin 3), and Ground (Pin 8) to your computer serial port as shown in
Figure 2. Adapter cables are available from the manufacturer or they can be constructed in the field with
parts from an electronics supply house. In Figure 2, note that the diagrams represent the “port” side of
the connections, i.e. the connector on top of the meter and the physical DB-9 serial port on the back of
the computer. The cable ends will be mirror images of the diagram shown in Figure 2. (See page 17 for
details on accessing RS-232 output.)
Standard Voltage (0-5 Vdc) Output Signal
All M and V series flow meters have a 0-5 Vdc (optional 0-10 Vdc) output signal available on Pin 6. This
is generally available in addition to other optionally ordered outputs. This voltage is usually in the range
of 0.010 Vdc for zero flow and 5.0 Vdc for full-scale flow. The output voltage is linear over the entire
range. Ground for this signal is common on Pin 8.
Optional 0-10 Vdc Output Signal
If your meter was ordered with a 0-10 Vdc output signal, it will be available on Pin 6. (See the Calibration
Data Sheet that shipped with your meter to determine which output signals were ordered.) This voltage
is usually in the range of 0.010 Vdc for zero flow and 10.0 Vdc for full-scale flow. The output voltage is
linear over the entire range. Ground for this signal is common on Pin 8.
Optional Current (4-20 mA) Output Signal
If your meter was ordered with a 4-20 mA current output signal, it will be available on Pin 1. (See the
Calibration Data Sheet that shipped with your meter to determine which output signals were ordered.)
The current signal is 4 mA at 0 flow and 20 mA at the meter’s full scale flow. The output current is
linear over the entire range. Ground for this signal is common on Pin 8. (Current output units require
15-30Vdc power.)
Note: This is a current sourcing device. Do not attempt to connect it to “loop powered “ systems.
Optional 2nd Analog Output Signal
You may specify an optional 2nd analog output on Pin 2 at time of order. (See the Calibration Data
Sheet that shipped with your meter to determine which output signals were ordered.) This output may
be a 0-5 Vdc, 0-10 Vdc, or 4-20 mA analog signal that can represent any measured parameter. With this
optional output, a volumetric flow meter could output the volumetric flow rate with a 0-5 Vdc signal (on
pin 6) and a 4-20 mA signal (on pin 2), or a mass flow meter could output the mass flow rate (0-5 Vdc
on pin 6) and the absolute pressure (0-5 Vdc on pin 2).
Note: This is a current sourcing device. Do not attempt to connect it to “loop powered “ systems.