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Module T8433
Issue 11 Apr 10 PD-T8433 12
1.5. Line Monitoring Thresholds
The module determines the contact state and line fault status by comparing the input current level to
four user programmed thresholds and two fixed (minimum and maximum) thresholds. Hysteresis is
provided on the thresholds by up-scale and downscale values, corresponding to the thresholds for
increasing and decreasing values respectively.
Default
threshold values
(mA)
Input
Channel
State
Line Fault
Status
Over-range 6 1
Tmax 24.0
High-High 5
0
T8 18.25
4 or 5
1
T7 17.75
High 4 0
T6 13.25
3 or 4 0
T5 12.75
Normal 3 0
T4 9.75
2 or 3
T3 9.25
Low 2
0
T2 6.25
1 or 2
T1 5.75
Low-Low 1 1
Tmin -2.0
Under-range 0
1
Table 1 Example Threshold data (4-20mA)
Default threshold values used for non line monitored inputs are as follows (in raw units)
Default = 448,576,1344,1472,2240,2368,3520,3648.
1
The channel state value returned is dependent on the previous state value. If the input level is
increasing then the lower state value will be returned. If the input level is decreasing the higher state
value will be returned.