The external pressure library works to retrieve the pressure measurements from an external pressure sensor, and write the pressure value back to the SME.
The followings steps describe the guidelines to activate the External Pressure sensor readings:
1. In the measurements tab, in status, the manual entry must be disabled
Figure 1. Disabling Manual Entry for Pressure.
2. Then in settings tab, in Pressure Gauge communication, select External Pressure. 
Figure 2. Selecting Communication with External Sensor
3. When selected. The software will prompt for the path of the external pressure Library. By default it will look for it in the C:\ProgramData\RheonicsControlPanel folder.
Figure 4. When selecting a correct llb file the Configuration appears.
5. Once the external .llb file of the library is selected. The library will execute a first VI that will prompt for the communication settings. In the case of Additel library, for example, the library will prompt for the com port of the device, address and Device ID. But this may depend on the hardware being controlled. When the sensor is correctly set the device ID is then displayed on the settings tab:
Figure 5. Pressure Gauge with Custom Library
And the pressure gauge will start taking measurements, which will be displayed in the measurements tab. These will also be stored in the logfiles.
Figure 6. Measurement tab with external pressure sensor active.