Honeywell Touchpoint Pro Technical Handbook page 168

POTENTIAL OPERATING ISSUES
19.4.2 Ring Fault Type 2
Rationale:
If a Ring A circuit is faulty (e.g. between last module A-out and the CCB A-in) then the CCB Module 4 will loop back the data
from Ring A onto Ring B, and will tell the UI to show a fault message for 'Ring A fault before CCB'.
Investigation:
Check the Ring A circuit from the last module A-out to the CCB A-in.
19.4.3 Ring Fault Type 3
Rationale:
If a Ring B circuit is faulty (e.g. between M1 B-in and M2 B-out) then Module 1 will not receive B-in and this module will loop
back the data from Ring A onto Ring B. The CCB will have both A-in and B-in but no B-out, and will tell the UI to show a fault
message for 'Ring B : Module 1' to show that the fault lies between M1 and M2.
Investigation:
Check the Ring B circuit from M1 B-in to M2 B-out.
19.4.4 Ring Fault Type 4
Rationale:
If a Ring B circuit is faulty (e.g. between M4 B-in and CCB B-out) then Module 4 will loop back the data from Ring A onto
Ring B, and the CCB will tell the UI to show a fault message for 'Ring B : Module X' (where X is the last module in the chain).
Investigation:
Check the Ring B circuit from CCB B-out to the last module B-in.
Part. No. 2400M2501_6
Figure 99. Ring Fault Type 2
Figure 100. Ring Fault Type 3
Figure 101. Ring Fault Type 4
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Touchpoint Pro
Technical Handbook