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5 The transmitter unit
In the hand-held remote control unit, apart from the radio transmitter module, there is an
encoder, which formats the control data for transmission, and a battery charge management
unit, which permanently monitors the state of the internal battery.
5.1 Charging the hand held transmitter unit
There is a 4.8V NiMH battery permanently installed in the transmitter. The charging cycle of
this battery is controlled by the battery charge management unit.
There are two metal belt loops on back of the transmitter unit. These loops are also the
charging contacts for the internal NiMH battery. These contacts are short circuit protected!
The battery can be charged by slotting the transmitter onto the LG2 battery charger, or any
12V
DC
source can be used to charge the battery by connecting it accross the two belt loops
(the polarity does not matter).
5.2 Battery charging cycle
When the transmitter is put on to charge the internal circuitry first discharges the battery
completely, to prevent damage to the battery and to maximise its working life of about 1000
charging cycles. The battery is then charged from flat. The discharging can take up to sixty
minutes, and the charging can take up to eight hours.
N.B. The complete charge needs
minimum nine hours
and the temperature shouldn`t be
below
0°C (32°F).
If the battery is discharged to 30% (for example) of its capacity during the day’s work, when
it is put on to charge, the internal charging circuitry will first discharge the battery completely,
then begin to charge it. This means that putting the unit on to charge for a short time when
the battery is not completely flat may, in fact, decrease the residual charge in the battery.
Important:
Charge the transmitter over-night by leaving it on the LG2 charger or
connecting it to any 12V
DC
voltage (polarity does not matter). If you want to use
the charging function during a working break please push together the buttons
Gas- and Gas+
after putting the transmitter on the charger. This charging is
limited to one hour
.
5.3 Low battery warning
If the residual charge in the battery decreases to about 10% of its maximum capacity, while
in operation, the operator will be warned via the vehicle horn: It will sound for about 1 sec
each time any button on the transmitter is pressed (except the
Stop
button). This ten
percent is sufficient for a further four to five hours normal work, but this warning informs the
driver that the battery is almost flat and should soon be put on to charge.
A completely charged battery allows a couple of days of operation, depending on how much
the transmitter unit is used: The battery capacity is enough for about 18 hours continuous
transmission (pressing any button permanently).
Summary of Contents for HM 2225
Page 17: ...17 9 View on the pc board of the receiver ...
Page 18: ...18 10 Block diagram of the receiver ...
Page 20: ...20 ...