Transmitters constitute a more versatile approach to continuous monitoring than the standard Loop powered sensors. The transmitters are capable of wider frequency and amplitude ranges and can provide a dynamic vibration signal in addition to the overall 4-20 mA output. The dynamic vibration signal is available through a buffered output. Figure 3 shows an example of the dual outputs of CTC’s Vibration Transmitter.
The 4 wires needed to monitor overall vibration level using a transmitter are the Positive and Negative Power Supply leads that will provide power to the electronics, and the Positive and Negative Output SIGNAL leads. These 2 pairs of leads are separate and distinct from one another. Figure 4 shows typical wiring into a PLC or Process controller with analog input module.
A 2 conductor cable with a Plug (F) type BNC Connector can be used to monitor the dynamic vibration signal coming out of the BNC Jack on the Transmitter.
Source - Connection Technology Center