NI TB-2709 Installation Guide 6 ni.com

Measuring Ground-Referenced Signals

It is possible to set the switch on the TB-2709 to either the floating or
ground-referenced source position to measure ground-referenced signals.
However, for best results, use the OFF (ground-referenced source) switch
position to avoid ground loops. Refer to the S Ser ies User Manual for more
information on measuring floating and ground-referenced signals.
Cabling Options
This section describes the cabling options for accessing digital signals on
the TB-2709.
A 14-pin connector on the bottom of the TB-2709 provides access to
digital I/O signals. Use the MFIT-Pigtail Cable Assembly (part number
194123-01) to access digital signals on the TB-2709. The MFIT-Pigtail
Cable Assembly features a 14-pin I/O connector on one end and pigtail
Table 2. Configuration Summary
TB-2709 Switch
Configuration
Signal Source Types for SSeries Devices
Floating Source Ground-Referenced Source
Floating Source
Ground-
Referenced Source
+
–
Signal
Source TB-2709
DAQ Device
(Differential Input
Mode)
AI GND
+
–
Recommended
+
–
Signal
Source TB-2709
DAQ Device
(Differential Input
Mode)
AI GND
+
–
Not Recommended
+
–
Signal
Source TB-2709
Improper Configuration
DAQ Device
(Differential Input
Mode)
+
–
AI GND
+
–
Signal
Source TB-2709
DAQ Device
(Differential Input
Mode)
AI GND
+
–
Recommended