tams elektronik GBM-8.2 User manual

GBM-8.2
Track Occupancy Indicator
8-fold
Manual
Item no. 52-01186 52-01187
tams elektronik
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GBM-8.2 tams elektronik
Version: 1.0 | Status: 12/2022
© Tams Elektronik GmbH
All rights reserved, in particular the right of reproduction, distribution and translation. Copies,
reproductions and alterations in any form require the written permission of Tams Elektronik
GmbH. We reserve the right to make technical changes.
Printing the manual
The formatting is optimised for double-sided printing. The standard page size is DIN A5. If
you prefer a larger display, printing on DIN A4 is recommended.
The asterisks
The asterisks indicate further products from the Tams Elektronik GmbH product range :
Track occupancy indicator GBM-1 Item numbers 52-01015, 52-01016, 52-01017
s88 feedback module S88-3 Item numbers 44-01305, 44-01306, 44-01307
s88 feedback module S88-6 Item numbers 44-01606, 44-01607
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tams elektronik GBM-8.2
Contents
1. Getting started.............................................................................................................4
1.1. Contents of the package.......................................................................................4
1.2. Accessories..........................................................................................................4
1.3. Intended use.......................................................................................................4
1.4. Safety instructions................................................................................................5
1.5. Care....................................................................................................................5
2. Operation overview.......................................................................................................6
2.1. Use in analogue layouts........................................................................................6
2.2. Use in digital systems...........................................................................................7
3. Connections GBM-8.2....................................................................................................8
3.1. Connecting the power supply and the track sections...............................................8
3.3. Connection of LEDs............................................................................................10
3.4. Connection of digital feedback modules...............................................................11
4. Setting the sensitivity..................................................................................................12
5. Checklist for troubleshooting and error correction.........................................................13
5.1. Technical Hotline................................................................................................13
5.2. Repairs..............................................................................................................13
6. Technical data............................................................................................................14
7. Warranty, EU conformity & WEEE................................................................................16
7.1. Guarantee bond.................................................................................................16
7.2. EU Declaration of Conformity..............................................................................17
7.3. Declarations on the WEEE Directive.....................................................................17
Contents 3

GBM-8.2 tams elektronik
1. Getting started
The instructions will help you step by step with the safe and proper installation and use of
your track occupancy indicator. Before you put the track occupancy indicator into operation,
read this manual completely, especially the safety instructions and the section on possible
errors and their elimination. You will then know what you have to pay attention to and thus
avoid errors that sometimes can only be rectified with a lot of effort.
Keep the instructions in a safe place so that you can restore functionality later in the event of
any malfunctions. If you pass the track occupancy indicator on to another person, also give
the instructions with it.
1.1. Contents of the package
1 ready-built and tested circuit board GBM-8.2 (item no. 52-01186-01) or
1 track occupancy indicator GBM-8.2 in housing (item no. 52-01187-01)
1.2. Accessories
Connection cables
The use of stranded wire is recommended for making the connections. Stranded wires consist
of several thin individual wires and are therefore more flexible than rigid wires with the same
copper cross-section. Recommended cross-sections:
Connections to the tracks and the booster / the driving transformer: > 0.25 mm²
Connections to digital feedback modules: > 0,10 mm²
Displaying the occupancy messages
If you want to display the busy signals, you will need
LEDs and suitable series resistors (e.g. 1 k)
for connection to AC voltage additionally:
1 electrolytic capacitor 10...100 µF / 25 V
1 diode 1N400x, x = 2...7
Monitoring of switched off track sections
To be able to monitor track sections that are to be switched off during operation (e.g. in the
staging yard), you need additional resistors with a value of max. 1.5 k.
1.3. Intended use
The track occupancy indicator is intended for use in model railway layouts as specified in the
instructions. Any other use is not in accordance with the intended use and will result in the
loss of the warranty claim. Intended use also includes reading, understanding and following all
parts of the instructions. The track occupancy indicator is not intended to be used by children
under the age of 14.
4 Getting started

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tams elektronik GBM-8.2
1.4. Safety instructions
Note:
The track occupancy indicator contains integrated circuits (ICs). These are sensitive to
electrostatic charging. Therefore, do not touch these components until you have
"discharged" yourself. For this purpose, e.g. a grip on a radiator is sufficient.
Improper use and non-observance of the instructions can lead to incalculable hazards. Prevent
these dangers by carrying out the following measures:
Only use the track occupancy indicator in closed, clean and dry rooms. Avoid moisture and
splash water in the environment. After condensation has formed, wait two hours for
acclimatisation before use.
Disconnect the track occupancy indicator from the power supply before carrying out wiring
work.
Supply the track occupancy indicator only with extra-low voltage as specified in the
technical data. Use only tested and approved transformers.
Only plug the mains plugs of transformers into properly installed and fused earthed sockets.
When making electrical connections, ensure that the cable cross-section is sufficient.
Heating of the track occupancy indicator during operation is normal and harmless.
Do not expose the track occupancy indicator to high ambient temperatures or direct
sunlight. Observe the information on the maximum operating temperature in the technical
data.
Regularly check the operational safety of the track occupancy indicator, e.g. for damage to
the connection cables.
If you notice damage or if malfunctions occur, disconnect the connection to the power
supply immediately. Send the track occupancy indicator in for inspection.
1.5. Care
Do not use any cleaning agents to clean the track occupancy indicator. Only wipe the track
occupancy indicator dry. Disconnect the indicator from the power supply before cleaning.
Getting started 5

GBM-8.2 tams elektronik
2. Operation overview
The GBM-8.2 track occupancy detector can monitor up to eight independent track sections. It
can be used in analogue and digital model railway layouts of all nominal sizes with a
maximum current consumption of 6 A per track section.
Adjustable sensitivity
The "correct" sensitivity at which a current consumer in a section is detected by the track
occupancy detector depends on several factors: If, for example, vehicles whose axles are
coated with resistive paint are to trigger an occupancy signal, a very high sensitivity is
required. In digital systems, however, high sensitivity can become a problem if interference
voltages from the digital system cause false alarms. Therefore, a lower sensitivity is usually
recommended for use in digital systems.
With the GBM-8.2, the sensitivity is adjusted separately for each track section at a trimmer
potentiometer and adapted to the individual requirements.
Evaluation of the busy signals
As soon as the GBM-8.2 detects a current consumer in a connected track section, the
corresponding output is internally connected to the output M. The output of the GBM-8.2 thus
acts like a switch that switches to ground. Digital feedback modules that switch to ground
(e.g. s88 feedback modules) can be connected directly to the outputs.
Display of the busy messages
To display the busy messages, LEDs (with suitable series resistors) can be connected to the
outputs of the GBM-8.2. Since the outputs of the GBM-8 can be loaded with a maximum of
50 mA each, they are not suitable for connecting incandescent lamps, relays or downstream
circuits with a higher current consumption. For these applications, the 4-fold track occupancy
detector GBM-1** is suitable.
Power supply
The GBM-8.2 is supplied with power directly via the rails. The track sections must be in one
booster circuit or supplied via a common driving transformer.
2.1. Use in analogue layouts
A typical application in analogue DC or AC systems is the use as part of a block position
control or an automated control system.
With the appropriate sensitivity setting, the GBM-8.2 detects vehicles with a current
consumption of at least 1 mA (e.g. illuminated locomotives or wagons) located in the
connected sections. Even the small current that flows in DC systems when an axle of a vehicle
is coated with resistive paint is sufficient to generate an occupancy signal when the sensitivity
is set to the lowest setting.
In principle, the GBM-8.2 can only detect vehicles in analogue DC systems that enter the
monitored track section from one direction of travel. Note: If the detection of vehicles from
both directions of travel is required, it is recommended to use a GBM-1** track occupancy
detector instead of a GBM-8.2.
6 Operation overview

tams elektronik GBM-8.2
2.2. Use in digital systems
The GBM-8.2 can be used independently of the digital format with which the layout is
controlled. A typical application in digital systems is the combination with feedback modules
that read in ground contacts (e.g. s88 feedback modules). The eight outputs of the GBM-8.2
are arranged in such a way that they can be directly connected to the inputs of the s88
feedback modules from the Tams Elektronik product range (e.g. S88-3** or S88-6**).
In digital systems, a high sensitivity of the occupancy sensor can become a problem if
interference voltages from the digital system cause false alarms. With the GBM 8.2, the
sensitivity can be set separately for each track section at a trim potentiometer so that
interference from the digital system has no influence on the busy signals.
The inputs and outputs of the GBM-8.2 are galvanically separated from each other by
optocouplers. This filters out interference peaks and effectively prevents ground loops ("hum
loops") and fault currents.
Info: Galvanic isolation
In digital layouts, the circuits for
supplying the tracks and the
digital devices can either be
galvanically (i.e. electrically)
separated from each other or
connected to a common,
continuous ground. Establishing
a common, continuous ground is
prone to errors in practice and
therefore unreliable, especially in
larger layouts.
With the use of galvanically
separated circuits, ground loops
("hum loops") and fault currents,
which can cause malfunctions
and in the worst case damage to
the digital devices, can be
reliably prevented.
With track occupancy detectors
such as the GBM-8.2, the inputs
(for connecting the monitored
track sections) are galvanically
separated from the outputs (for
connecting digital feedback
devices). The signals (i.e.
occupancy messages) are passed on, but no electrical energy.
Operation overview 7

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GBM-8.2 tams elektronik
3. Connections GBM-8.2
The module is equipped with modular terminals into which you insert the connection cables
and screw them tight.
3.1. Connecting the power supply and the track sections
Connections to 2-rail systems
Connections to 3-rail systems
Connecting the power supply
Please note that all track sections must be in one booster circuit or must be supplied via a
common driving transformer.
GBM-8.2 Track output of the booster or the driving transformer
V1 + / ~ Please note: If you use a DC voltage transformer as the
driving transformer, you must always observe the polarity when
connecting it. If you use an AC voltage transformer, the polarity is
not important.
V2 - / 
8 Connections GBM-8.2

tams elektronik GBM-8.2
Connecting the track sections
The busy status can only be reported trouble free, if one conductor is isolated at both ends of
each section to be monitored:
3-rail systems: centre conductor or both rails
2-rail systems (analogue): "-" rail
2-rail systems (digital): one of the two rails
Please note that, due to the principle, in analogue 2-rail systems (DC systems) only vehicles
are detected that enter the track section in the direction marked as "direction of travel" in the
connection diagram.
GBM-8.2 Connection to
G1, G2, G3, … G8 isolated conductors in the track sections
V1 uninterrupted conductor
Monitoring of switched-off track sections
Track sections that are to be switched off during operation (e.g. in a staging yard) can also be
monitored with the GBM-8.2. For this purpose, a resistor with a value < 1.5 kW must be
installed in the supply line to the track section concerned in such a way that it bridges the
switch in the switched-off state.
3.2.
Connections GBM-8.2 9

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GBM-8.2 tams elektronik
3.3. Connection of LEDs
To display the busy signals (e.g. in
analogue systems), connect the
cathodes (-) of LEDs (with series
resistors, e.g. 1 kΩ) to the outputs of
the GBM-8.2.
Always with series resistor!
Never operate LEDs without a series
resistor, the LEDs will be destroyed
very quickly in this case!
Separate transformer!
Do not use the driving transformer for
the power supply of the LEDs, but a
separate transformer, e.g. to supply
other lights! If you use the driving
transformer to supply the LEDs, the
equalising currents that occur can
damage connected components.
Supply with alternating voltage
If you connect the LEDs to an AC transformer, you should also connect a protective diode
(e.g. 1N400x, x=2...7) and a capacitor with a capacity between 10 and 100 µF and a dielectric
strength of at least 25 V. This will prevent the LEDs from flickering.
No incandescent lamps!
Never connect incandescent lamps to the outputs, as they usually consume more than 50
mA of current. The outputs of the GBM-8.2, which are designed for a maximum current of
50 mA, would be destroyed during commissioning!
10 Connections GBM-8.2

tams elektronik GBM-8.2
3.4. Connection of digital feedback modules
You can connect the inputs of digital feedback modules that switch to ground (e.g. s88
feedback modules) directly to the outputs of the GBM-8.2. Connect the ground output of the
feedback module to one of the two connections M of the GBM-8.2.
Connections GBM-8.2 11

GBM-8.2 tams elektronik
4. Setting the sensitivity
Adjust the sensitivity of the track occupancy detector for each of the 8 track sections at the
associated trim pot. Use a small screwdriver for the adjustment.
Settings:
Left stop: highest sensitivity (setting on delivery)
Right stop: lowest sensitivity
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5. Checklist for troubleshooting and error correction
Warning: If you notice a strong heat development, immediately disconnect the
connection to the supply voltage. Fire hazard!
Possible causes:
One or more connections are faulty. à Check the connections.
The GBM-8.2 is defective. à Send the track occupancy indcator in for inspection.
Connected LEDs do not light up
Possible causes:
The power supply is interrupted. à Check the connection of the LEDs and the track
occupancy detector to the transformer supplying the LEDs.
One or more LEDs are defective. à Check the LEDs by connecting them directly (via a
series resistor) to the power supply.
Occupied sections are not recognised
Possible causes:
The sensitivity for the relevant track section is set too low. à Check the position of the
corresponding trim pot and correct the setting (left stop = highest sensitivity).
5.1. Technical Hotline
If you have any questions about the use of your track occupancy indicator, our technical
hotline will help you (telephone number and e-mail address on the last page).
5.2. Repairs
You can send us a defective track occupancy indicator for repair (address on the last page). In
the event of a warranty or guarantee claim, the repair is free of charge for you. As proof of
any warranty or guarantee claim, please enclose the proof of purchase with your return.
If there is no warranty or guarantee claim, we are entitled to charge you the costs of the
repair and the costs of the return shipment. We charge a maximum of 50% of the new price
for the repair according to our valid price list. We reserve the right to refuse the repair if it is
technically impossible or uneconomical.
If you want to clarify whether a repair is possible or economical before sending it in, please
contact our Technical Hotline (telephone number and email address on the last page).
Please do not send us repair shipments freight collect. In the event of a warranty or guarantee
claim, we will reimburse you for the regular shipping costs.
Checklist for troubleshooting and error correction 13

GBM-8.2 tams elektronik
6. Technical data
Number of
monitored sections maximum 8
Evaluation of the
occupancy messages against mass of the downstream components
Galvanic isolation between inputs and outputs
Inputs and outputs
Inputs 8 inputs for the connection of the monitored track sections
Outputs 8 outputs for the connection of
the inputs of downstream feedback devices and/or
LEDs for displaying the occupancy status
Electrical characteristics
Power supply via the rails
Note: All track sections must be in one booster circuit or
supplied via a common driving transformer.
Current consumption
(without connected loads) approx. 15 mA
Max. current
in the track sections 6.000 mA per rail section
Max. current per outpu 50 mA
Sensitivity 1 mA … 
separately adjustable for each of the 8 track sections at a
trim potentiometer
Protection
Protection class Ready-made module (without housing): IP 00
Meaning: No protection against foreign bodies, contact and water.
Ready device (in housing): IP 20
Meaning: Protected against solid foreign bodies with diameter ≥ 12.5 mm and
access with a finger. No protection against water.
14 Technical data

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Environment
For use in closed rooms
Ambient temperature during
operation 0 ~ + 30 °C
Permissible relative humidity
during operation 10 ~ 85% (non-condensing)
Ambient temperature
during storage - 10 ~ + 40 °C
Permissible relative humidity
during storage 10 ~ 85% (non-condensing)
Other features
Dimensions (approx.) Circuit board: 63 x 97 mm
Ready device including housing: 100 x 98 x 35 mm
Weight (approx.) Assembled board (ready-made module): 43 g
Ready device including housing: 91 g
Technical data 15

GBM-8.2 tams elektronik
7. Warranty, EU conformity & WEEE
7.1. Guarantee bond
For this product we issue voluntarily a guarantee of 2 years from the date of purchase by the
first customer, but in maximum 3 years after the end of series production. The first customer
is the consumer first purchasing the product from us, a dealer or another natural or juristic
person reselling or mounting the product on the basis of self-employment. The guarantee
exists supplementary to the legal warranty of merchantability due to the consumer by the
seller.
The warranty includes the free correction of faults which can be proved to be due to material
failure or factory flaw. With kits we guarantee the completeness and quality of the
components as well as the function of the parts according to the parameters in not mounted
state. We guarantee the adherence to the technical specifications when the kit has been
assembled and the ready-built circuit connected according to the manual and when start and
mode of operation follow the instructions.
We retain the right to repair, make improvements, to deliver spares or to return the purchase
price. Other claims are excluded. Claims for secondary damages or product liability consist
only according to legal requirements.
Condition for this guarantee to be valid, is the adherence to the manual. In addition, the
guarantee claim is excluded in the following cases:
if arbitrary changes in the circuit are made,
if repair attempts have failed with a ready-made module or device,
if damaged by other persons,
if damaged by faulty operation or by careless use or abuse.
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7.2. EU Declaration of Conformity
This product fulfils the requirements of the following EU directives and therefore
bears the CE marking.
2001/95/EU Product Safety Directive
2015/863/EU on the restriction of the use of certain hazardous substances in electrical and
electronic equipment (RoHS)
2014/30/EU on electromagnetic compatibility (EMC Directive). Underlying standards:
DIN-EN 55014-1 and 55014-2: Electromagnetic compatibility - Requirements for household
appliances, electric tools and similar electrical appliances. Part 1: Emitted interference, Part 2:
Immunity to interference
To maintain electromagnetic compatibility during operation, observe the following measures:
Only connect the supply transformer to a professionally installed and fused earthed socket.
Do not make any changes to the original components and follow the instructions, connection
and assembly diagrams in this manual exactly.
Only use original spare parts for repair work.
7.3. Declarations on the WEEE Directive
This product is subject to the requirements of the EU Directive 2012/19/EC on Waste Electrical
and Electronic Equipment (WEEE), i.e. the manufacturer, distributor or seller of the product
must contribute to the proper disposal and treatment of waste equipment in accordance with
EU and national law. This obligation includes
registration with the registering authorities ("registers") in the country where WEEE is
distributed or sold
the regular reporting of the amount of EEE sold
the organisation or financing of collection, treatment, recycling and recovery of the
products
for distributors, the establishment of a take-back service where customers can return WEEE
free of charge
for producers, compliance with the Restriction of the Use of Certain Hazardous Substances
in Electrical and Electronic Equipment (RoHS) Directive.
The "crossed-out wheeled bin" symbol means that you are legally obliged to
recycle the marked equipment at the end of its life. The appliances must not be
disposed of with (unsorted) household waste or packaging waste. Dispose of the
appliances at special collection and return points, e.g. at recycling centres or at
dealers who offer a corresponding take-back service.
Warranty, EU conformity & WEEE 17

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Further Information and Tips:
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Warranty and Service:
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Tams Elektronik GmbH n
Fuhrberger Straße 4
DE-30625 Hannover
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fon: +49 (0)511 / 55 60 60
fax: +49 (0)511 / 55 61 61
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e-mail: [email protected] n
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