SCC-CO20

2 SINK

+ –

0–20 mA

1 ISO GND

Load

I

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 μA.

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 μA. 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.

SCC-CO20 Isolated Current Output Module User Guide

8

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