The Field Inspection Tool (FIT) is a portable handheld device with a user interface that is used to test and troubleshoot the BACnet® protocol MS/TP RS-485 communications bus that connects supervisory controllers and field controllers to field point interfaces.
The FIT can be used to check out the wiring of the MS/TP RS-485 bus as well as verify proper communications of supervisory controllers and field controllers connected to the bus. The FIT can be used on both the Field Controller Bus (FCB) and Sensor Actuator Bus (SAB).
The FIT can perform the following functions on the FC/SA Bus:
- Measure bus bias voltage levels
- Communicate with controllers and provide:
- - Number of Devices Online
- - Device addresses
- - Model Name
- - Application Name
- - Firmware Revision
- - Status of End of Line (EOL) termination switch
- - Measure RS-485 communication voltage levels from controller
- - Other controller attributes
- Monitor and report communication errors
For more information on MS/TP basics see, MS/TP Communication Basics and the FIT.