Siemens SLD4 - SLD4 Sensitivity

General Setup
Loop Detector Application Notes SLD4
667/HQ/45200/101
10
Link Function
Link
Function
PL3
Loop 1 inductance setup links
PL4
Loop 2 inductance setup links
PL5
Loop 3 inductance setup links
PL6
Loop 4 inductance setup links
Table 3 : Link and Switch Function
Sensitivity Settings
Range
Jumper Setting
Inductance Range
1
1-2, 3-4
20-150uH
2
2-3, 4-5
150uH-300uH
3
1-2 ,4-5
260uH-2000uH
Table 4 : Inductance Jumper Settings for Detection
Note
In practice inductance ranges overlap so it is possible to use a lower range in some circum-
stances. This may give better performance, particularly for bicycle detection.
2.2. SLD4 Sensitivity
The detector threshold may either be set in “Hz” or as a percentage of loop inductance
change (%ΔL/L ). Which you use only depends upon which is most convenient for the applica-
tion. In general, it is recommended that “Hz” mode is used for large vehicles (tram, bus), as
this provides easier value adjustment for large vehicles. The value is a whole number in the
thousands range, for an inductance change it would be a two decimal place number.
The “Hz” setting is slightly dependent upon frequency, so if you change the loop frequency
then the sensitivity in “Hz” may need to be changed higher or lower in proportion to the loop
frequency change. This is the disadvantage of using the “Hz” setting mode.
Detector Variant Differences
The standard SLD4 detector supports only “Bicycle” mode whereas the remaining modes re-
quires an enhanced SLD4 detector.