Measuring the loop cable resistance and capacitance
Power-down and disconnect both ends of the
loop
wiring by pulling out the associated terminal blocks at the control panel.
Resistance measurement
¨
Using a
multimeter
measure the resistance between the
loop L1 0V
(End 1) and loop L2
0V
(End 2). In practice this should not be greater than
13 ohms.
Capacitance measurement
¨
Check the capacitance between the
loop 0V
and
cable screen
. The capacitance should not be greater than
1.0uF.
Also the cable End-1 and End-2 should read the same value.
When to use the 'Repair' function on the loop circuit
When a loop circuit is tested for short circuit fault or if a genuine wiring short circuit fault should occur, then rectification action must be taken. First rectify the wiring fault and then
process the
'Repair'
command at the control panel. You will need to be at Access level 2 or above to activate the repair function.
Commissioning instructions
30
4188-949 issue 3_05/10_Nano Comms inst.
Measuring
the
loop
cable
resistance
and
capacitance
10:15 Tue 16/02/10
Warning!- Ensure that the loop wiring faults
have been cleared before continuing
with this function!
Yes
No
ARE YOU SURE YOU WANT TO PROCEED?
Select
Loop
>
Select
User
Menu
Repair
Select
You will need to run the ‘Repair’ function
after a loop short fault is rectified.
Yes
