Measurement Computing USB-7204 - Manual (Page 13)

USB-7204 User's Guide Functional Details
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Figure 4. Screw terminal pinout
Signal connections
Analog input
You can connect up to eight analog input connections to the screw terminal containing pins 1 to 20 ( CH0 IN
through CH7 IN .) Refer to Figure 4 above for the location of the analog input pins.
You can configure the analog input channels as eight single-ended channels or four differential channels. By
default, differential mode is configured at power-up.
Single-ended configuration
When configured for single-ended mode, each analog input has 11-bit resolution, due to restrictions imposed by
the A/D converter. With single-ended mode, the input signal is referenced to signal ground and delivered
through two wires:
 The wire carrying the signal to be measured connects to CH# IN.
 The second wire connects to AGND.
The input range for single-ended mode is ±10 V.
Single-ended measurements using differential channels
To perform a SE measurement using differential channels, connect the signal to the "CH# IN HI" input, and
ground the associated "CH# IN LO" input.
Differential configuration
When configured for differential mode, each analog input has 12-bit resolution. In differential mode, the input
signal is measured with respect to the low input and delivered through three wires:
 The wire carrying the signal to be measured connects to CH0 IN HI, CH1 IN HI, CH2 IN HI, or
CH3 IN HI.
 The wire carrying the reference signal connects to CH0 IN LO, CH1 IN LO, CH2 IN LO, or
CH3 IN LO.
 The third wire connects to GND.