Uhlenbrock 67800 User guide

Servo decoder 67 800

For connection 4 Servos

Characteristics

• For Märklin and DCC Digital systems

• Switchable like a solenoid decoder

• Switching address for each servo freely selectable

• Adjustable stop positions

• Adjustable rotating speed

• 4 stopping positions via 2 addresses in the DCC operation

• Backlash function, e.g. for boom gates or semaphore signals

• Configurable via the turnout keys of digital systems

or by DCC CV programming

• Powered from the track or separate transformer

• Very low power usage by integrated regulator

• Servo output with overload protection

Description

The servo decoder allows you to use Servos, as commonly employed in modeling, to solve
mechanical control problems on the model railway layout. For example, with the appropriate
mechanics the Servos can change turnout positions, move water cranes in, open doors of
locomotive sheds, operate boom gates and much more.

Up to four Servos can be connected to a servo decoder and operated independently of each
other. The servo decoder works like a turnout decoder and in a digital system is assigned a
solenoid address for each servo. By using digital systems, the solenoid controlling the servo
can be brought to two stop positions. The servo decoder operates with all DCC and Motorola
Digital systems.

The Servos’ stops for the two solenoid positions "red" and "green" can be independently
configured. The speed with which the servo moves between the two stops can also be
adjusted.

For special applications each of the attached servos can have two additional independent
stops by assigning two additional solenoid addresses. This way mechanical items like water
cranes can be moved between four positions via two solenoid addresses.

The servo decoder also has a “rocker” function which can be used for boom gates or
semaphore signals. If the servo reaches a stop it then bounces a little before it stops
completely. The rocker movement amplitude and speed can be adjusted.

1 Address, both stops and the rotating speed for each servo are separately setup with simple
key programming from Motorola and DCC centers.

In the case of use of a DCC center like the Intellibox all parameters can be programmed by
CV programming. That way, 2 addresses, their stops, the rotating speed and the rocker
function can be separately setup for each servo.

Installation of Servo decoders 67 800

Connecting the Servo decoder

The terminals labeled “Gleis” (track) are connected with the track terminals of a DCC or
Motorola Digital center. In this case the decoder is supplied via the track power.

Note: Since most Servos move uncontrolled, when supply voltage is switched on (this is a
servo characteristic and is not produced by the servo decoder), we recommend that the
decoder is also connected to a 16V model railway transformer via the "trafo" terminals. The
uncontrolled movements of the Servos then only occur when the entire layout is switched on.

Connecting the Servos to the Servo Decoder

Each servo decoder has four 3-pin headers for connecting a maximum of four Servos. The
Servo’s plugs are plugged onto the appropriate header so that the earth wire (usually black
or brown) is at the front edge of the circuit board.

Header pin assignment

Earth - PCB front edge
5V - middle
Control wire - back

Tip: If the distance from the servo to the servo decoder is too far you can extend the lead
without any difficulty. Servo cables with plug and socket are available in specialized
electronics outlets.

Programming

From a DCC center, the decoder can be programmed by keys and solenoid instruction or by
using CV programming.

With key programming not all items can be used.

Item Key programming CV Programming
Data format X X
Addresses 1 2
Stop positions 2 4
Switching time X X
Whip function - X
Selection whether the servo is always to be switched

on or only during servo movement

Programming by Key and Solenoid Command
All settings for the stops and the servo speed are easily set by the digital center, or another

control device, with which one can control solenoids.
The desired servos should be connected to the outputs that are to be programmed since the

servo decoder acknowledges the setting of the servo parameters, during programming, with
a movement of the respective servo.

1. Activating Programming Mode

Press the key on the decoder and keep it pressed. The control LED blinks.

2. Selecting Data Format

The LED blinks alternately at flashing rate A and flashing rate B for 5 seconds in each case.
Meaning:
Blinking rate A = __ __ __ = selection DCC format
Blinking rate B = _ _ _ _ _ _ = selection Motorola format
If the key is released during the appropriate blinking rate then the appropriate data format is

selected.

Note: If the decoder no longer reacts to key inputs from the input device, the wrong data
format was selected! Programming must be repeated.

- X