Connecting Differential Measurements

You can use a differential measurement configuration to attain more accurate measurements and less noise. A differential measurement configuration requires two inputs for each measurement, thus reducing the number of available channels on the TS-15100 to 16. The following table shows the signal pairs that are valid for differential connection configurations with the TS-15100.

Table 2. Differential Pairs
Channel AI + AI-
0 AI 0 AI 8
1 AI 1 AI 9
2 AI 2 AI 10
3 AI 3 AI 11
4 AI 4 AI 12
5 AI 5 AI 13
6 AI 6 AI 14
7 AI 7 AI 15
16 AI 16 AI 24
17 AI 17 AI 25
18 AI 18 AI 26
19 AI 19 AI 27
20 AI 20 AI 28
21 AI 21 AI 29
22 AI 22 AI 30
23 AI 23 AI 31

For an illustration of connecting a device to the TS-15100 using differential connections, refer to the following figures.

Note The signal names AI 0- (AI 8) and AI 1- (AI 9) indicate the differential pair. Refer to the previous table for a list of differential signal pairs.
Figure 7. Connecting Floating Differential Connections to the TS-15100

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To connect floating differential signals to the TS-15100, you must connect the negative signal to COM through a 1 MΩ resistor to keep the voltage within the maximum working voltage. If the voltage source is outside the maximum working voltage, the TS-15100 does not read data accurately.

Figure 8. Connecting Grounded Differential Connections to the TS-15100

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In a differential configuration, the TS-15100 rejects the common-mode noise voltage during the measurement of V1. To connect grounded differential signals to the TS-15100, you must also connect the signal reference to COM.