2.2 DC Current Source
2-4
IM CA500-01EN
Description
Source Range
You can select from the following four source ranges.
Range
Source Range
20 mA
±24.000 mA
4-20 mA
0.000 mA to 24.000 mA
4-20 mA√
0.000 mA to 24.000 mA
4-20 mA Sim
0.000 mA to 24.000 mA
4-20mA
The interval between 0% and 100% is equally divided by four, and the 0%, 25%, 50%, 75%,
and 100% values are output. By default, because the 0% value is assigned to 4.000 mA
and the 100% value is assigned to 20.000 mA, this can be used as a calibration signal for
instruments that use 4 to 20 mA as input signals.
Square Root Computation Function (4-20 mA√)
This can be used as a calibration signal for instruments that output the square root of input
signals.
DC currents corresponding to the square root of 4 mA, 8 mA, 12 mA, 16 mA, and 20 mA are
generated.
4-20 mA Simulate
Currents ranging from 0 to 20 mA that simulate transfer signals are generated. This can be
used to perform a loop check on the source value by connecting to a distributor or the like.
4-20mA
+
—
Distributor
Output 1 to 5 V
H
L
CA500/CA550
Source Value
Currents within each source range are generated.
In the default setting of the 4-20mA and 4-20mA Simulate ranges, 4 mA to 20 mA are divided into
four, and 4 mA, 8 mA, 12 mA, 16 mA, and 20 mA are generated.
In the default setting of the 4-20mA√ range, 4 mA to 20 mA are divided into four, and values
corresponding to the square root of 4 mA, 8 mA, 12 mA, 16 mA, and 20 mA are generated.
Source value = (%/100)×(%/100)×(100% value - 0% value) + 0% value
In the 4-20mA√ range, 0% = 4 mA and 100% = 20 mA, so for 25% = 8 mA,
Source value = (25/100)×(25/100)×(20 mA - 4 mA) + 4 mA = 5 mA.
Notes about Sourcing
Be careful not to open the output terminals.
When the output terminals are opened, the output is automatically turned off by the protection
function.
