TELELIFT 3713 SX
TECHNICAL SPECIFICATIONS
0
Document 57.4402.9200 - 1
st
Edition 10/2006
INDEX
.
TECHNICAL SPECIFICATIONS
Electrical specifications
•
Supply voltage:
12 ÷ 15 Vdc
•
Maximum current:
350 mA
•
Fuse (external):
0.5 A F (fast-acting) 5x20mm
•
Protected against power inversions
Environmental
•
Temperature:
-20 ÷ 50 °C
•
Humidity (non-condensing):
95%
Inputs/outputs
•
Stabiliser status input
Input voltage:
10 ÷ 15 V
Input current:
30 mA
•
Alarm relay output
Output voltage:
12 V
Maximum load:
200 mA
Load cell specifications
•
Excitation voltage:
5 V
•
Sensitivity:
1 mV/V
4.
OPERATION
The output from the load cell is a signal of a few milliVolt,
which depends on the weight applied on the cell and on
the excitation voltage of the cell. The nominal excitation
voltage of the load cell is 5 V; in practice it may vary
between 4.75 V and 5.25 V.
Remember that the number of LEDs that are lit is
inversely proportional to the output voltage of the load
cell. When the load on the cell decreases (because the
boom is being extended, for example), the output of the
load cell also decreases, but the number of LEDs that
are lit increases from right to left.
When the fifth LED lights up, the buzzer sounds and
current stops flowing from the alarm output (pin
8
on
connector
B
). This output is connected to the coil of a
relay which, upon opening, controls a solenoid valve
that locks out the extension and descent movements of
the boom.
The alarm is deactivated when the stability of the machine
returns within safety (the red LED turns off) and after
approximately a 3-second delay, in order to allow any
oscillations of the machine to dampen out.
When both stabilisers are lowered, a positive voltage
(10 V minimum) is present at the stabiliser input (pin
7
). The “
S
” on the display lights up and the instruments
changes range.
To ensure a stable display, the turn-on threshold of every
LED is different from its turn-off threshold. For example,
suppose that a weight of 1010 kg is applied on the cell,
that the turn-on threshold of a LED corresponds to a
weight of 1000 kg and the turn-off threshold to a weight
of 1005 kg. If the weight on the cell is gradually reduced,
the LED turns on when the weight is less than 1000 kg.
To turn the LED off again, the weight on the cell must
increase above the turn-off threshold (1005 kg). This
hysteresis ensures that every LED is steadily on or off,
in spite of the vibrations of the vehicle.
The fifth LED (alarm) has a greater hysteresis compared
to the other LEDs: when the alarm is activated, this
ensures that the stability of the vehicle is well back within
safety before the alarm is deactivated.
LED 5
LED 4
LED 3
LED 6
LED 1
LED 2
Fig. 3
Summary of Contents for Telelift 3713 SX
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