Measurement Computing Data Translation DT3034, User Manual

Page: 46 / 178

Wiring Signals
45
Connecting Analog Input Signals
The DT740 screw terminal panel supports both voltage and current loop inputs. You can
connect analog input voltage signals to the screw terminal panels in the following
configurations:
• Single-ended – Choose this configuration when you want to measure high-level signals,
noise is not significant, the source of the input is close to the screw terminal panel, and all
the input signals are referred to the same common ground. When you choose the
single-ended configuration, all 32 analog input channels are available.
• Pseudo-Differential – Choose this configuration when noise or common-mode voltage
(the difference between the ground potentials of the signal source and the ground of the
screw terminal panel or between the grounds of other signals) exists and the differential
configuration is not suitable for your application. This option provides less noise rejection
than the differential configuration; however, all 32 analog input channels are available.
• Differential – Choose this configuration when you want to measure low-level signals
(less than 1 V), you are using an A/D converter with high resolution (greater than 12 bits),
noise is a significant part of the signal, or common-mode voltage exists. When you choose
the differential configuration, 16 analog input channels are available.
Note: We recommend that you connect all unused analog input channels to analog ground.
This section describes how to connect single-ended, pseudo-differential, and differential
voltage inputs, as well as current loop inputs to the screw terminal panels.
Connecting Single-Ended Voltage Inputs
Figure 5 shows how to connect single-ended voltage inputs to the DT740 screw terminal
panel.
Figure 5: Connecting Single-Ended Voltage Inputs to the DT740
(Shown for Channels 0 and 1)
+
DT740 Panel
Signal Source

Vsource
0
TB1
TB3
TB33
Analog In 0
Analog In 1
TB2
Jumper W1
Installed
(Amp Low)
W1
TB34
Analog Ground
+

Vsource
1