Ceia THS - Accessory Devices; Photocell - General Rules; Photocell Self-Diagnosis; Ejector - General Rules

THS – FI022GB2K8v3 --- V - MAINTENANCE
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Accessory devices
Photocell – General rules
Programming
parameters
Meaning Generally applied setting
THS/STD THS/SL THS/3F THS/G THS/M THS/PH
PD Distance between metal
detector and photocell
At the entrance to the probe: 0-2000 mm
At the exit from the probe: see table II-C
50-2000
mm
_
PH Position of the photocell
relative to the probe
IN : installed at the entrance to the probe
OUT: installed at the exit from the probe
IN _
IP Type of “Photocell” input NC,NO _
The photocell should naturally be placed at a height whereby it can have a clear view of the objects on the conveyor belt.
Photocell installed at the entrance to the probe
F
S
N
PD
When installed at the entrance to the probe, the
photocell distance should be within the range 50mm to
2 m
Photocell installed at the exit from the probe
F
S
N
PD
Fig.II-24. N: conveyor belt; S: electronics unit; F: photocell;
d: distance photocell- electronics unit
When installed at the exit from the probe, the photocell
distance (PD in the figure) depends on the belt speed,
but should not in any case be less than that indicated in the
following table:
Table II-C
Belt speed (metres/min) Minimum distance photocell-
electronics unit (mm)
< 20 50
20 50
30 60
40 100
50 130
60 160
70 190
80 230
90 260
>
100 290
Photocell self-diagnosis
If the photocell is in a continuously active state for a long period, this is interpreted as a malfunction of the sensor by the
self-diagnosis system. There are many possible causes (wrong position, short-circuited wiring etc.).
The self-diagnosis message may appear:
- in the case of a conveyor belt without encoder or with Power Control Box, with the belt stopped or moving
- in the case of a conveyor belt without encoder or with Conveyor Control System, with the belt moving.
The system is not designed to signal a pack which is stuck for some reason in front of the photocell. For this reason,
when the system can detect whether or not the conveyor belt is moving (i.e. when it is equipped with an encoder or with
the Conveyor Control System power supply unit), the self-diagnosis function gives an alarm only if the photocell is in a
state of malfunction when the belt is moving.
On systems without encoder or with the Control Power Box, it is the installer’s and operator’s responsibility to ensure that
material does not remain in front of the photocell when the belt is stopped: if it does, the photocell will be continuously
active even though it is not malfunctioning. If the foregoing situation can not be avoided, it is advisable to disable
photocell self-diagnosis (Parameter PA)
Ejector – General rules