Explanation
Measurement Function (Function)
There are three measurement functions: mA MEASURE, mA LOOP, and V MEASURE.
mA MEASURE: The CA700 can measure DC current in the range of –20 mA to +20 mA or –100 mA
to +100 mA.
mA LOOP: The CA700 measures current while applying 24 VDC across the measurement
terminals.
DC current in the range of 0 mA to +20 mA can be measured.
This
can
be
used
in
transmitter
loop tests.
V MEASURE: The CA700 can measure DC voltage in the range of –5 to 5 V or –50 to 50 V.
Averaging
The CA700 can take a moving average of the measured values.
Relative and min/max values are calculated using averaged values.
When averaging is set to ON, “AVG” is displayed on the screen.
Scaling, Alarm, Percentage Display, and Relative Display
These items are the same as with pressure measurement. See section 2.1.
Measurement Range (for mA MEASURE and V MEASURE)
mA MEASURE: You can switch between 20 mA range and 100 mA range. Select the appropriate
range for the measured values.
20mA:
–20.000 mA to +20.000 mA
100mA: –100.00 mA to +100.00 mA
V MEASURE: You can switch between 5V range and 50V range. Select the appropriate range for
the measured values.
5V:
–5.0000V to +5.0000V
50V:
–50.000V to +50.000V
Loop Voltage (for mA LOOP)
You can turn on and off the loop voltage applied across the measurement terminals.
The MEASURE mA terminal is negative, and the SOURCE mA/V terminal is positive.
When you turn on the loop voltage, 24 VDC is applied across the MEASURE mA terminal and the
SOURCE mA/V terminal.
CA700
SOURCE
MEASURE
V mA
mA/V
COM
4 to 20 mA
24 VDC
+
–
Distributor
Two-wire transmitter
+
–
LOOP POWER
Saving Data
You can save the current and voltage values along with the pressure measurement data.
For details, see sections 4.1 and 2.1.
2.4 Measuring DC Current and DC Voltage
2-20
IM CA700-01EN