FIT Connection to Bus - Metasys - LIT-12012443 - Software Application - MS-FIT100-0 Field Inspection Tool

MS-FIT100-0 Field Inspection Tool User Guide

Product name
MS-FIT100-0 Field Inspection Tool
Document type
User Guide
Document number
Revision date

The FIT is provided with a RJ-12 connector cable that is connected to the FC/SA 6 pin RJ-12 jack found on most Johnson Controls® controllers. The FIT also has a Four-Pin removable terminal block that is used to wire the FIT to the FC/SA bus. When the FIT is connected to the FC bus, it can only see the devices directly connected on the FC bus, but not the SA bus. Conversely, when the FIT is connected to the SA bus, it can only see the devices on the SA bus, but not the FC bus.

It is best to connect the FIT tool to the bus and then power it up. Assuming communication is occurring, the FIT first has to determine the baud rate of the communication signal before it can read the communication messages. If the FIT is powered before it is connected to the bus, the mechanical connection causes the bus voltage to be unstable for a time, which can cause the FIT to mistake the proper baud rate. The occurrence of this issue is unlikely, but it can occur. When no communication is occurring (the bus is in a fixed idle state), the FIT initially displays Offline.