Measurement-computing USB-1208LS Bedienungsanleitung PDF herunterladen (Seite 11)

USB-1208LS User's Guide Functional Details

The differential mode pinout is shown in Figure 4.

Figure 4. Differential mode pinout

Signal connections

Analog inputs

You can connect up to eight analog input connections to the screw terminal containing pins 1 to 20 (CH0 IN

through CH7 IN).

You can configure the analog input channels as eight single-ended channels or four differential channels. When

configured for differential mode, each analog input has 12-bit resolution. When configured for single-ended

mode, each analog input has 11-bit resolution, due to restrictions imposed by the A/D converter.

Single-ended configuration

When configured for single-ended input mode, eight analog channels are available. The input signal is

referenced to signal ground (GND), and delivered through two wires:

 Connect the wire carrying the signal to be measured to CH# IN.

 Connect the second wire to GND.

The input range for single-ended mode is ±10V.

To perform a single-ended 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 input mode, four analog channels are available. In differential mode, the input

signal is measured with respect to the low input, and delivered through three wires:

 Connect the wire carrying the signal to be measured to CH# IN HI.

 Connect the wire carrying the reference signal to CH# IN LO.

 Connect the third wire to GND.

A low-noise precision programmable gain amplifier (PGA) is available on differential channels to provide gains

of up to 20 and a dynamic range of up to 12-bits. Differential mode input voltage ranges are ±20 V, ±10 V,

±5 V, ±4 V, ±2.5 V, ±2.0 V, 1.25 V, and ±1.0 V.

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Measurement-computing USB-1208LS Bedienungsanleitung Seite 11