Graupner Receiver GR-12S HoTT : User's Manual : Page 3

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09 Manual Receiver GR-12 Graupner HoTT 2.4

2.3. Fail-Safe function

In its default state (as delivered) the receiver is set to “Hold” mode, i.e. if a fail-safe situation occurs, all

the servos connected to it maintain the last position detected as valid. In this mode the green LED on

the receiver starts ﬂ ashing when interference occurs, and the red LED on the transmitter goes out. The

transmitter also starts beeping about once per second as an audible warning.

You can exploit the safety potential of the fail-safe option by at least programming the throttle channel to

respond to a fail-safe situation: the throttle channel of an engine-powered model should be set to idle,

the throttle channel of an electric-powered model to “stop”, and the throttle channel of a model helicopter

to “Hold”. If interference should occur, these settings will help prevent the model ﬂ ying out of control,

possibly causing personal injury or property damage.

Please refer to the appropriate section in your RC system instructions for the procedure.

Manual Receiver GR-12 Graupner HoTT 2.4 02

3. RECEIVER

3.1 Connections

Plug the servos into the row of sockets on the right-hand end of the receiver. The connector system is

polarised; note the small chamfer on one edge. Never use force - the plugs should engage easily and

fully. The socket polarity is also marked on the case: brown wire (-), red (+) and orange (signal).

The servo sockets of the Graupner-HoTT 2.4 receiver are numbered. The socket marked “- +/B” is

intended for the battery. If necessary, a servo can be connected to this socket in parallel with the power

supply; a Y-lead (Order No. 3936.11) is required for this.

t is also possible to program channel 6 for the sum signal using the SMART-BOX (Order No. 33700).

This is important for certain optional devices which require this signal.

Servo sockets

Telemetry socket

(channel 5)

Power supply for receiver 33506

When using High Power servos, connect the receiver power supply/s preferably to the vertical ports of

the receiver. If necessary, the servos can be connected to this sockets in parallel with the power supply;

a Y-lead (Order No. 3936.11) is required for this.

When using a dual power supply, use the sockets on the outside:

Receiver 33506 (GR-12): Channel 1 and 6 (or 2 and 5)

The socket marked “5” - channel 5 - is intended for the optional telemetry sensors and is used for loading

ﬁ rmware updates in conjunction with the USB interface. When using the receiver GR-12S (Order No.

33505) the adapter cable Order No. 23048 is also needed.

Note: with telemetry sensors connected to socket 5, servos will not longer work at this output!

3.2. Low voltage warning

If the receiver voltage falls below 3.8 V, the transmitter’s RF module generates a low voltage warning in

the form of a “general alarm sound”: a steady beeping at intervals of about one second.

Channel 1 and 6