Connecting Input Signals

You can connect floating and grounded input signals to the FieldDAQ device. Make sure that devices you connect to the FieldDAQ device are compatible, as listed in the FD-116xx Specifications.

The FD-116xx provides an IEPE excitation current for each channel to measure the IEPE sensors. Typical IEPE sensors have a case that is electrically isolated from the IEPE electronics. As a result, connecting the sensor to the FD-116xx results in a floating connection even though the case of the sensor is grounded.

• Floating Signal Sources

  

  Figure 1. Connecting Floating Signal Sources to the FieldDAQ Device

• Grounded Signal Sources—To ensure proper operation, make sure the voltage on the AI+ and AI- connections adhere to the channel-to-earth ground safety voltage specifications listed in the FD-116xx Specifications.

  

  Figure 2. Connecting Grounded Signal Sources to the FieldDAQ Device