Domburg ASB User manual

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DTS
Manual
DTS Manual:
Analogue Servo Control ASB
Version 2 - 2019

Manual ASB │ version 2 – 2019
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Content
Introduction ......................................................................................................................................................... 3
How the ASB works ............................................................................................................................................. 4
The functionality of the ASB ............................................................................................................................ 4
Possibility’s to control the ASB ........................................................................................................................ 4
Mounting ............................................................................................................................................................. 5
Servo bracket ................................................................................................................................................... 5
Servo ................................................................................................................................................................ 5
Spring steel wire .............................................................................................................................................. 6
Aansluiten ............................................................................................................................................................ 7
Power ............................................................................................................................................................... 8
Servo’s .............................................................................................................................................................. 8
Rocker switches ............................................................................................................................................... 8
Relay ................................................................................................................................................................. 9
Configuring the controller ................................................................................................................................. 10
Resetting the ASB ........................................................................................................................................... 10
Fault status ..................................................................................................................................................... 11
FAQ .................................................................................................................................................................... 11
The heat sink of the print gets hot, is that a problem? ................................................................................. 11
When I switch on the power supply, the servos convulse ............................................................................ 11
Epilogue ............................................................................................................................................................. 11

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Introduction
Thank you for purchasing the Analogue Servo Control ASB. This item has been specially developed for
users who would like to operate their switches and barriers beautifully and reliably by hand. A controller
that is unique in its kind and that offers an answer to a frequently asked lack. There are many users for
whom digital control is still a bridge too far, or who simply do not find digital control of accessories
interesting. This group of users controls their switches and scenery by hand with switches on a control
panel. A way that is well known to every model railroader. These users often use magnetic controls for
points, signals and barriers. A solution that has many disadvantages compared to servo control.
Servo control is not only cheaper to buy, but also many times more economical, reliable and beautiful
than the click-on magnets. However, you usually need a hardware for servo control with software to
operate the servos. Here are some solutions for this through a handful of small print providers. However,
these solutions lack the ability to switch a relay with a servo. These relays have two changeover contacts,
which makes it possible to polarize heart pieces and create feedback for the position of the change.
Until now this was only possible with an OC32 or self-build through Arduino. However, this is a great
solution for the advanced and experts among us. But for the normal model railroader there was no
solution yet, until now!!!
I wish you much ease of use with the ASB, if you have suggestions for improving the product or a critical
note. Let me know by sending an email to [e-mail]
Sincerely,
Martin Domburg

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How the ASB works
The functionality of the ASB
The ASB works based on a PIC interface with a code with which it can function. For the PCB to work
properly, the power supply offered is reduced to 5VDC, which allows the PIC to operate the servos and
the relay.
Each servo is controlled via a switch. The most used is the rocker switch, but any switch that retains its
position is suitable for this. A link is made to the middle position of a servo in the internal code with a
relay. As soon as the servo has reached its middle position, it switches the relay on or off depending on
the position taken.
To determine the servo positions and speed, three push buttons are present namely: Plus, Enter and Min.
The internal code can be set with these three buttons.
As mentioned, the ASB can control two servos, but it does not do this simultaneously. If you control a
servo and immediately control the second, the print will first convert the first servo and then the second
servo. This is built into the code to prevent the interface from missing a command. This makes the servos
work more reliably.
Possibility’s to control the ASB
With the relay it is possible to perform several functions by means of two changeover contacts per relay.
Some of the most common:
 Point polarization of a switch
 LED status notification on a control panel
 Activation of an MP3 player (e.g. the AVT 100 series MP3 player)
 Switching of a signal position to the switch position
 Switching blocks to the switch position
This is a selection of the many options. If you have applied a new option, please let me know. I can collect
and process this in this manual.

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Mounting
The ASB has 4 mounting points. It is advisable to mount the printed circuit board at height due to the
heat development of the voltage regulator. Preferably with the components on top.
Mounting the ASB in upside down or sideways position is also possible if you consider the cooling of the
cooling element.
For the assembly you can use the printed circuit board assembly kit which
you can find in the webshop.
Servo bracket
The MDF Servo brackets consist of 3 separate parts. A base plate stands and partition.
You must glue the 3 parts together with preferably wood glue. Hobby glue and hot glue are also good.
Note the partition, it only fits well in one way. Then the sides are the same. You can use the bracket by
Mount the supplied sheet screws on your layout.
Servo
The servo has several arms. Choose the arm that you wish to use and mount it on the servo. Be sure to
use the small screw to secure the arm to the servo shaft.
You must now position the servo in the bracket in this way and screw it into the servo bracket with two
plate screws.

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Spring steel wire
The spring steel wire can be used to affect the transfer between the servo arm and the object to be
moved. You do this as directly as possible. Every kind of bending, Z-cut and V-cut are not necessary and
counteract the movements.
The most common way of mounting is right under the switch tongue, making the distance and movement
of the servo as short as possible. You can use the different holes in the arm to play with the stroke of the
servo. If the stroke is too short or too fast, you can prefer a hole closer to the axis. If you want a direct
movement, choose a hole as far as possible from the axis.
The distance from the arm to the servo is irrelevant, if you cover more than 5 cm perpendicular to the
arm and in line with the movement of the servo, it is advisable to use a tube to guide the spring steel.
Tip: use the cotton buds for this. That saves you a lot in your wallet.

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Aansluiten
Figure 1
V + Positive voltage between 7-35 VDC
GND Well-known minus, or the Ground
Servo 1 First servo connection
Servo 2 Connection second servo
S1 Rocker switch associated with servo 1
S2 Rocker switch associated with servo 2
Servo1 Contact 1 First changeover contact of relay 1 associated with servo 1
Servo1 Contact 2 First changeover contact of relay 1 associated with servo 1
Servo2 Contact 1 First changeover contact of relay 1 associated with servo 1
Servo2 Contact 1 First changeover contact of relay 1 associated with servo 1

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Power
The supply voltage that must be offered on the ASB is a direct voltage of a minimum of 7 volts and a
maximum of 35 volts. A voltage between 12 and 15 volts is recommended. Offering an alternating
voltage is not allowed, if you do this can cause irreparable damage to the printed circuit board and its
components.
If you have an alternating voltage you can solve this by using a bridge rectifier circuit as shown below in
figure 2 by means of a few simple parts such as a bridge cell rectifier and an Elko capacitor.
source Wikipedia
Figure 2
On the two-pole terminal of the ASB you can offer the DC voltage as in figure 1. On the voltage regulator
side, you offer the positive voltage (V +) and on the other side the ground or better known as V- (GND).
If you have connected the polarity correctly, the green POWER LED lights up. If you connect the polarity
incorrectly, the ASB will not light a green power LED.
Servo’s
Connect the servos to the two three-pole headers with the text "servo 1" and "servo 2". It is important
that you connect the orange wire of the servo cable to the inside of the print. If you plug the plug in the
wrong way, the servo will show strange behaviour.
You can extend the servo cable if desired. You will find servo extension cables 30, 50 and 100 centimetres
long in the webshop.
Rocker switches
You offer the two rocker switches on the four-pole terminals next to the servo connection. The two left
terminals (S1) are a set and belong to servo 1. The two right terminals (S2) are the second set and belong
to servo 2.
The rocker switches each have 3 contacts, identical to those of the relay. You connect one terminal to the
middle leg of the rocker switch, the other terminal to either the left or the right leg of the rocker switch.
You repeat this with two wires for the second set of terminals.
Incidentally, it is not necessary to use a rocker switch. Any switch that switches between two contacts is
enough to operate the servo.

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Relay
Each servo has a relay that switches to the middle position of the servo. As shown in figure 1, each relay
has two changeover contacts. This means that every contact consists of a Common (COM), Normally
Closed (NC) and Normally Open (NO). We have indicated this more easily by a few letters per contact:
P: Common
A: Normally Closed
B: Normally Open
In principle you can forget the above again. You connect the supply wire of what you want to switch to
the P, then the contact switches this voltage to either A or B. This depends on the position of the relay.
If you want to polarize a switch:
1. Solder a wire to the point of the switch and connect it to terminal P (middle terminal of a contact)
2. Solder a wire to the rail, which is straight, it feeds the heart piece when bent. Connect this to
terminal B
3. Solder a wire to the rail, which is bent, this will feed the heart piece in the straight-through
position. Connect this to terminal A
4. Measure with the multimeter after switching the servo or the correct rail led to the heart piece
5. If this is not the case, exchange A and B
If you want to make a status message with an LED:
1. Connect the long leg of the LED (cathode) to the V + of the power supply.
2. Connect the short leg of the LED (Anode) to the A or B terminal of a contact. Depending on the
status message determined by the position of the servo.
3. Connect the GND of the power supply to terminal P.
Figure 3

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Configuring the controller
Each servo has its own characteristics due to its mechanical transmission from motor to gears. As a result,
the results of the servos cannot be programmed in advance. You determine the result per servo by
programming it in the ASB. This operation does not take much time but is very essential. On the printed
circuit board, you will see three push buttons with the text Plus, Min and Enter. You will need these keys
for programming.
There are 8 steps to go through of which 4 per servo:
Step 1: Left position servo 1
Step 2: Medium servo 1
Step 3: Right position servo 1
Step 4: speed servo 1
Step 5: Left position servo 2
Step 6: Medium servo 2
Step 7: Right position servo 2
Step 8: speed servo 2
To enter programming mode, you must keep the Enter key pressed for 3 seconds. After releasing the
button, the red PROGRAM LED lights up and you are directly in step 1. Go through steps 1 to 8.
You determine the result of the servo by using the PLUS and the MIN key.
When you have finished a step, press ENTER to go to the next step. You will then see the red LED go out
temporarily.
After step 8, both servos go into the middle position and the ASB is ready for use. If desired, you can
repeat the steps, the fact is that the order is fixed. You can also walk through the steps without making a
change. The ASB then remembers the position that the servo is currently in.
Resetting the ASB
It is possible that the programming did not go well, or you are not satisfied with the settings and want to
perform them again. You can of course go through the steps again. However, you can also reset the
entire ASB.
You can do this by keeping the PLUS and MIN button pressed simultaneously for 2 seconds in normal
operation. You hear the servos give a blow and the ASB is reset again.
This does not work in PROGRAM mode to protect your settings.

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Fault status
The centre of the servo is very important for the ASB because the left and right results are measured with
the middle position. If this position is not programmed between the two results, the servo will get into a
"loop" in which it travels a path and shoots back to the start and then repeats this. This is an indication
that the middle position is not set correctly.
FAQ
The heat sink of the print gets hot, is that a problem?
No this is not a problem; it is also normal that it gets hot. The voltage regulator is responsible for
this and switches itself off at 125 degrees Celsius. As an indication, at 45 degrees the average
person feels that it is too hot to touch.
When I switch on the power supply, the servos convulse
That is correct and is caused by the servos themselves. The cheaper servos such as the HXT900 and
TG9 or even the Towerpro series are analogue servos. As soon as the voltage is switched on, they
get a small peak, which causes them to bump. This shouldn’t be any issue.
Epilogue
I have written this manual for general use. You do not have to pay for this manual and it can be
downloaded free of charge on our website. If you want to copy the text for private or club use, please
contact us.
I hope this manual will help you connect the ASB. If you have any comments or remarks, please let me
know. I can then process this in a new version. You can report this by sending an email to
[e-mail]
Thank you for reading and using this manual.
Sincerely,
Martin Domburg