operating instructions
VEK FG2-1
16
12/99
FEIG ELECTRONIC GmbH
8 Malfunctions
Detector does not align correctly or not at all
Possible reasons
Measures
Break of loop or short
circuit
Verification: measure resistance and inductivity of the loop with an LCR-meter.
- total resistance has to be between 0 and 20
Ω
.
- total inductivity has to be between 50 and 1000
µ
H.
Remedy: eliminate the source of errors, install new loop resp. loop feeder.
Insulation defect
Verification: check insulating resistance of the loop and feeder between feeder end and earth potential with
the
help of an insulation tester, such as the Isolavi. The insulating resistance has to be higher than
2 M
Ω
.
Remedy: eliminate the source of errors, install new loop resp. loop feeder
Inductivity is too high
Verification: check inductivity with an LCR-meter.
Total inductivity of loop and loop feeder must not exceed 800
µ
H .
Remedy: - install interstage transformer VEK ANPASS into the loop feeder.
- install a new loop with less turns. (see „loop installation“)
Inductivity is too low
Verification: check inductivity with an LCR-meter.
Total inductivity of loop and loop feeder has to exceed 30
µ
H.
Remedy: -install interstage transformer VEK ANPASS into the loop feeder.
- install a new loop with more turns. (see „loop installation)
Resistance is too high
Verification: check resistance with an LCR-meter or multimeter.
Total resistance of loop and loop feeder has to be less than 20
Ω
.
Remedy: reduce loop feeder resistance by
- connect two leads in parallel
- use a cable with a greater diameter
Loop feeder is too long
Verification: check feeder length between detector and induction loop according to detector data sheet.
Remedy: -install interstage transformer VEK ANPASS between detector and loop feeder.
- place the detector resp. loop elsewhere.
Couplings caused by
deficient frequency
separation
Verification: check frequencies of all loops with diagnostic device VEK FG2. Frequency separation of
neighbouring loops has to be at least 5 kHz (VEK V..-types) resp. 10 kHz (VEK M..-types).
Note:
For multiplex detectors (VEK M...), frequency separation is not necessary for loops of one
detector.
Remedy: re-adjust loop frequencies and check with diagnostic device VEK FG2.
Couplings caused by
insufficient distance bet-
ween neighbouring
loops
Verification: the minimum distance between neighbouring loops has to be half the length of the parallel loop
edges.
Note:
There is no minimum distance between the loops of one detector for multiplex detectors (VEK
M...)
Remedye: Install loops with a greater distance in between.
Interference at the loop
Verification: check fluctuations in
detuning
mode with the helo of diagnostic device VEK FG2. They must
not
exceed 2 increments.
Remedy: - choose another frequency level.
-
Use of an 8-loop makes the loop more insensitive to interferences.
-
Note: compared to square loops, 8-loops reduce the responsiveness of the system!
Interference at the loop
feeder
Verification: check fluctuations in
detuning
position with the help of diagnostic device VEK FG2 .
Fluctuation
must not exceed 2 increments.
Remedy: - the loop feeder has to be thoroughly twisted (min. 25 turns/m).
- do not install the loop feeder together with other live leads in one cable pit.
- carry out interference elimination (toroidal core, filter, etc.).
Interference at the
detector
Verification: check fluctuations in the
detuning
position witht the help of diagnostic device VEK FG2. They
must
not exceed 2 increments.
The detector must not align automatically when switching loads (e.g. barrier motor).
Remedy: - connect the detector’s supply main to another phase.
- carry out interference elimination (toroidal core, filter, etc.).
Insufficient mechanical
solidity of the loop
Verification: tap the surface above the loop with a beam and observe diagnostic device VEK FG2 in
detuning
position with regard to possible frequency jumping or permanent detuning.
Note:
changes in the loop geometry may cause positive as well as negative detuning of the detector.
Positive detuning may lead to a permanent seizure of the detector. In case of negative detuning,
the
detector becomes more insensitive. Extreme frequency jumps may lead to a re-alignment of the
detector.
Remedy: -please make sure that the loop is of sufficient mechanical solidity; there must not be any
deformations in the loop geometry when crossing it with a vehicle.
- the loop must not move compared to the ground armouring.
- for installation under paving stones, please always use finished loops.
