SCC-CO20 Isolated Current Output Module
8
ni.com
Figure 5.
Connecting the SCC-CO20 to a Grounded External Loop Supply
and a Grounded Load
For information about how to configure the SCC-CO20 module using
NI-DAQmx, refer to the
SCC Quick Start Guide
.
Calibrating Gain and Offset Errors
The SCC-CO20 is calibrated at the factory before shipment. If you want
to adjust the gain and offset of the SCC-CO20 in your system using an
E/M Series DAQ device, you need a current meter (ammeter) with an
accuracy of at least
±
2
µ
A.
To adjust the gain and offset of the SCC-CO20, complete the following
steps:
1.
Disconnect the load from the SCC-CO20 you want to calibrate.
2.
Set an output range of 0 to 10 V for AO (
X
), the E/M Series DAQ
device channel connected to the SCC-CO20.
3.
Connect the negative lead of the ammeter to the current sink (pin 2)
and the positive lead to the current supply (pin 3) of the SCC-CO20.
4.
Using your software, have AO (
X
) output 10 mVDC.
5.
Adjust the offset potentiometer on the top of the SCC-CO20 until the
ammeter reads 20
µ
A. The offset is now calibrated.
6.
Using your software, have AO (
X
) output 9 VDC.
7.
Adjust the gain potentiometer on the top of the SCC-CO20 until the
ammeter reads 18 mA. The gain is now calibrated.
1
2
Load
0
–
20 mA
SINK
SCC-CO20
ISO GND
+
–
I
