tams elektronik GBM-1 User manual

GBM-1
Track Occupancy Indicator
4-fold
Manual
Item nos. 52-01015 52-01016 52-01017
tams elektronik
n n n

GBM-1 tams elektronik
Version: 2.0 | Status: 01/2023
© 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 t e 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.
** T e asterisks
The asterisks indicate further products from the Tams Elektronik GmbH product range :
Track occupancy indicator GBM-8 Item numbers 52-01085, 52-01086 and 52-01087
Track occupancy indicator GBM-8.2 Item numbers 52-01186 and 52-01187
2 Contents

tams elektronik GBM-1
Contents
1. Getting started.............................................................................................................4
1.1. Contents of the package.......................................................................................4
1.2. Accessories..........................................................................................................4
1.3. Intended use.......................................................................................................5
1.4. Safety instructions................................................................................................5
1.5. Care....................................................................................................................5
2. Operation overview.......................................................................................................6
3. Assembling the kit........................................................................................................8
3.1. Safety instructions................................................................................................8
3.2. Soldering properly................................................................................................9
3.3. Preparation........................................................................................................10
3.4. PCB layout and parts list.....................................................................................12
3.5. Assembly...........................................................................................................13
3.6. Performing a visual check...................................................................................14
3.7. Performing a functional test................................................................................14
4. Connecting the track busy indicator.............................................................................15
4.1. Pin assignment...................................................................................................15
4.2. Connections.......................................................................................................15
4.3. Connection of the track sections..........................................................................17
4.4. Connection to the voltage supply.........................................................................17
4.5. Connecting lamps or LEDs...................................................................................18
5. Connecting subordinate circuits...................................................................................19
5.1. Connection of digital feedback modules...............................................................19
5.2. Application example: Block section control...........................................................19
6. Checklist for troubleshooting and error correction.........................................................22
6.1. Technical Hotline................................................................................................23
6.2. Repairs..............................................................................................................23
7. Technical data............................................................................................................24
8. Warranty, EU conformity & WEEE................................................................................26
8.1. Guarantee bond.................................................................................................26
8.2. EU Declaration of Conformity..............................................................................27
8.3. Declarations on the WEEE Directive.....................................................................27
Contents 3

GBM-1 tams elektronik
1. Getting started
The instructions will help you step by step with the safe and proper assembly of the kit and
installation and use of your track occupancy indicator. Before you start to assemble the kit or
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 kit GBM-1 (item no. 52-01015-01), containing the components listed in the parts list
( section 3.4.) and one PCB or
1 ready-built and tested circuit board GBM-1 (item no. 52-01016-01) or
1 track occupancy indicator GBM-1 in housing (item no. 52-01017-01)
1.2. Accessories
To assemble t e kit you will need
a soldering iron with temperature control and a thin tip and a deposit stand or a controlled
soldering station
a scraper, rag or sponge
a heat-resistant pad
a small pair of side cutters and wire strippers
tweezers and flat-nose pliers if necessary
electronic solder (preferably 0.5 to 0.8 mm diameter)
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: > 0.25 mm²
Connections to the power supply: > 0.75 mm²
Connections to the booster / the driving transformer: > 0.75 mm²
Connections to lamps, LEDs, relays or other downstream consumers: depending on the
current consumption of the consumers
Function test
It is recommended to test the track occupancy indicator´s functions before mounting it into
the layout, especially if you have built the module from a kit. For this you need a light bulb.
4 Getting started

!
tams elektronik GBM-1
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.
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 module
dry. Disconnect the track occupancy indicator from the power supply before cleaning.
Getting started 5

GBM-1 tams elektronik
2. Operation overview
The track busy indicator GBM-1 can monitor a maximum of four independent track sections.
The four track sections have to be supplied by one common driving-transformer (in analogue
layouts) or must be situated in one booster section (in digital layouts).
Application
The track busy indicator GBM-1 is suitable for use in model railway layouts of all gauges
(without gauge II / G):
for visualisation of occupied track sections
to switch on and off further consumers depending on the occupancy status of the track
sections
as part of an automated control system, e.g. a block control system
The GBM-1 has been optimised for use in analogue layouts:
It is very sensitive and detects loads with a current of only 1 mA.
In analogue d.c. layouts it detects vehicles driving into the monitored track sections
independently of the direction of travel.
The four outputs of the GBM-1 can be loaded with 500 mA each, which enables the direct
connection of many consumers.
In principle, the GBM-1 can also be used in digital layouts with all digital formats, e.g. in
combination with digital feedback devices (e.g. s88 feedback devices). Due to the high
sensitivity of the GBM-1, interference voltages from the digital system can cause false alarms.
Therefore, instead of a GBM-1, the track occupancy detectors GBM-8 or GBM-8.2** are better
suited for use in digital systems.
Voltage supply
The GBM-1 must not be supplied by transformers or a digital boosters providing current for
driving operation. In order to supply the GBM-1 transformers or boosters can be used which
supply other track busy indicators or lighting modules as well.
Detection of ve icles
The GBM-1 detects vehicles consuming at least 1 mA (e.g. locomotives and carriages with
lighting) located in the connected section. In d.c. layouts the GBM-1 detects vehicles which
axles are painted with resistive lacquer and which apart from that are not consuming current.
When switching off track sections with a switch mounted between the track section and the
input of the GBM-1, the electric consumer located in the switched off track section can be
detected when
an additional resistor is mounted to bridge the switch and
at the same time the supply voltage is applied to the rail sections not monitored.
6 Operation overview

tams elektronik GBM-1
Evaluation of t e busy signals and connection of subordinate consumers
The evaluation of the track busy signals is done internally against ground. Thus, all consumers
whose inputs switch to ground can be connected to the outputs of the GBM-1 and triggered
depending on the occupancy status of the track sections.
Note: In principle, digital feedback modules that switch to ground (e.g. s88 feedback modules)
can also be connected to the outputs of the GBM-1. However, due to the high sensitivity of the
GBM-1, interference voltages from the digital system can cause false alarms.
The four outputs of the GBM-1 can be loaded with up to 500 mA. Many downstream circuits
can therefore also be connected directly and switched on or off depending on the occupancy
status of the track sections. Consumers that require a higher current must be switched via
relays.
Display of occupied messages
When a connected track section is occupied, the assigned LED on the track occupancy
indicator lights up. Additional lamps or LEDs (e.g. in a track diagram control panel) can be
connected to the four outputs assigned to the signal sections.
Note: If consumers are connected downstream that operate with a higher voltage than the
GBM, this can cause the LEDs on the module to light up dimly even though the connected
track sections are not occupied.
Operation overview 7

!
GBM-1 tams elektronik
3. Assembling the kit
You can skip this section if you have purchased a ready-built module or device.
3.1. Safety instructions
Mec anical azards
Cut wires can have sharp ends and can cause serious injuries. Watch out for sharp edges
when you pick up the PCB.
Visibly damaged parts can cause unpredictable danger. Do not use damaged parts: recycle
and replace them with new ones.
Fire risk
Touching flammable material with a hot soldering iron can cause fire, which can result in
injury or death through burns or suffocation. Connect your soldering iron or soldering station
only when actually needed. Always keep the soldering iron away from inflammable materials.
Use a suitable soldering iron stand. Never leave a hot soldering iron or station unattended.
T ermal danger
A hot soldering iron or liquid solder accidentally touching your skin can cause skin burns. As a
precaution:
use a heat-resistant mat during soldering,
always put the hot soldering iron in the soldering iron stand,
point the soldering iron tip carefully when soldering, and
remove liquid solder with a thick wet rag or wet sponge from the soldering tip.
Dangerous environments
A working area that is too small or cramped is unsuitable and can cause accidents, fires and
injury. Prevent this by working in a clean, dry room with enough freedom of movement.
Ot er dangers
Children can cause any of the accidents mentioned above because they are inattentive and
not responsible enough. Children under the age of 14 should not be allowed to work with this
kit or the ready-built module.
Caution:
Little children can swallow small components with sharp edges, with fatal results! Do not
allow components to reach small children.
In schools, training centres, clubs and workshops, assembly must be supervised by qualified
personnel. In industrial institutions, health and safety regulations applying to electronic work
must be adhered to.
8 Assembling the kit

tams elektronik GBM-1
3.2. Soldering properly
Use a soldering iron with temperature control, which you set to approx. 300 °C.
Only use electronic solder with a flux.
Never use soldering water or soldering grease when soldering electronic circuits. These
contain an acid that destroys components and conductor paths.
Insert the connecting wires of the components as far as possible through the holes of the
board without using force. The body of the component should be close above the board.
Make sure that the polarity of the components is correct before soldering them.
Solder quickly: soldering for too long can coffe pads or tracks to become detached or even
destroy components.
Hold the soldering tip on the soldering point in such a way that it touches the component
wire and the pad at the same time. Add (not too much) solder simultaneously. As soon as
the solder begins to flow, remove it from the soldering point. Then wait a moment for the
solder to flow well before removing the soldering iron from the soldering joint.
Do not move the component you have just soldered for about 5 seconds.
A clean, non-oxidised (scale-free) soldering tip is essential for a perfect soldering joint and
good soldering. Therefore, before each soldering, wipe off excess solder and dirt with a
damp sponge, a thick damp cloth or a silicone wiper.
After soldering, cut off the connecting wires directly above the soldering point with a side
cutter.
After assembly, always check each circuit again to ensure that all components are correctly
inserted and polarised. Also check that no connections or tracks have been accidentally
bridged with tin. This can lead not only to malfunction, but also to the destruction of
expensive components. You can re-liquefy excess solder with the clean hot soldering tip.
The solder then flows from the board to the soldering tip.
Assembling the kit 9

GBM-1 tams elektronik
3.3. Preparation
Put the sorted components in front of you on your workbench.
The separate electronic components have the following special features you should take into
account in assembling:
Resistors
Resistors reduce current.
The value of resistors for smaller power ratings is indicated through colour rings.
Every colour stands for another figure. Carbon film resistors have 4 colour rings.
The 4th ring (given in brackets here) indicates the tolerance of the resistor (gold
= 5 %).
Value: Colour rings:
470 yellow - violet - brown (gold)
1,5 k brown - green - red (gold)
10 kbrown - black - orange (gold)
47 kyellow - violet - orange (gold)
470 kyellow - violet - yellow (gold)
Ceramic capacitors
Among other things ceramic capacitors are used for filtering interference voltages
or as frequency determining parts. Ceramic capacitors are not polarized.
Normally they are marked with a three-digit number which indicates the value
coded. The number 104 corresponds to the value 100 nF.
Electrolytic capacitors
Electrolytic capacitors are often used to store energy. In contrast to ceramic
capacitors they are polarized. The value is given on the package.
Electrolytic capacitors are available with different voltage sustaining capabilities.
Using an electrolytic capacitor with a voltage sustaining capability higher than
required is always possible.
Diodes and Zener diodes
Diodes allow the current to pass through in one direction only (forward direction),
simultaneously the voltage is reduced by 0,3 to 0,8 V. Exceeding of the limit
voltage always will destroy the diode, and allow current to flow in the reverse
direction.
Zener diodes are used for limiting voltages. In contrast to "normal" diodes they
are not destroyed when the limit voltage is exceeded.
The diode type is printed on the package.
10 Assembling the kit

tams elektronik GBM-1
Lig t emitting diodes (LEDs)
When operated in the forward direction the LEDs light. They are available in
several different versions (differing in colour, size, form, luminosity, maximum
current, voltage limits).
Light emitting diodes should always be connected via a series resistor which limits
the current and prevents failure.
Transistors
Transistors are current amplifiers which convert low signals into stronger ones. There are
several types in different package forms available. The type designation is printed on the
component.
Transistors for a high power rating (e.g. BD types) have a flat package (TO-
package), which is in use in different versions and sizes.
The three pins of bipolar transistors (e.g. BD types) are called basis, emitter and
collector (abbreviated with the letters B, E, C in the circuit diagram).
Integrated circuits (ICs)
Depending on the type, ICs fulfil various tasks. The most common housing form is
the so-called "DIL"-housing, from which 4, 6, 8, 14, 16, 18 or more "legs" (pins)
are arranged along the long sides.
ICs are sensitive to damage during soldering (heat, electrostatic charging). For
that reason in the place of the ICs IC sockets are soldered in, in which the ICs are
inserted later.
Terminal strips
Terminal strips are solder-in screw-type terminals. They provide a solder-free and safe
connection of the cables to the circuit, which can still be separated any time.
Assembling the kit 11

GBM-1 tams elektronik
3.4. PCB layout and parts list
PCB layout
Parts list
Carbon film resistors R1 470 W
R4, R7, R10, R13, R14, R16, R18, R20 10 kW
R2, R3, R5, R6, R8, R9, R11, R12 470 kW
R15, R17, R19, R21 47 kW
R22 - R26 1,5 kW
Ceramic capacitors C1 - C8 100 nF
Electrolytic capacitors C9, C10 220 µF > 25 V
C11 - C14 22 µF > 16 V
Diodes D1 1N540x, x=2...7
D2 - D26 1N4148
D33 - D40 1N400x, x>1
Zener diodes D27 ZD 12 V
LEDs D28 - D31 3 mm, red
D32 3 mm, green
Transistors T1 - T4 BD679
ICs IC1 LM 339 N
IC-sockets IC1 14-pole
Terminal strips X1 - X3 4 x 3-pole
12 Assembling the kit

!
tams elektronik GBM-1
3.5. Assembly
Proceed according to the order given in the list below. First solder the components on the
solder side of the PCB and then cut the excess wires with the side cutter. Follow the
instructions on soldering in section 3.2.
Caution:
Several components have to be mounted according to their polarity. When soldering these
components the wrong way round, they can be damaged when you connect the power. In
the worst case the whole circuit can be damaged. At the best, a wrongly connected part will
not function.
1. Resistors Mounting orientation of no importance.
2. Wire bridges Br1 and
Br2
Use the off-cut wires of the resistors.
3. Diodes, Zener diodes Observe the polarity!
The negative end of the diodes is marked with a ring. This is
shown in the PCB layout.
4. IC sockets Mount the sockets that way, the markings on the sockets
show in the same direction as the markings on the PCB
board.
5. Ceramic Capacitors Mounting orientation of no importance.
6. Light emitting diodes
(LEDs)
Observe the polarity!
With wired LEDs the longer lead is always the anode
(positive pole).
7. Transistors Observe the polarity!
With transistors for a high power rating in TO packages (e.g.
BD types) the unlabelled back side is marked in the PCB
layout by a thick line.
8. Electrolytic capacitors Observe the polarity!
One of the two leads (the shorter one) is marked with a
minus sign.
9. Terminal strips Put together the terminal strips before mounting them.
10. ICs in DIL-housing Insert the ICs into the soldered socket.
Do not touch the ICs without first discharging yourself by
touching a radiator or other grounded metal parts.
Do not bend the "legs" when inserting them into the sockets.
Check that the markings on the PCB, the socket and the IC
show to the same direction.
Assembling the kit 13

!
GBM-1 tams elektronik
3.6. Performing a visual check
Perform a visual check after the assembly of the module and remove faults if necessary:
Remove all loose parts, wire ends or drops of solder from the PCB. Remove all sharp wire
ends.
Check that solder contacts which are close to each other are not unintentionally connected
to each other. Risk of short circuit!
Check that all components are polarised correctly.
When you have remedied all faults, go on to the next part.
3.7. Performing a functional test
It is recommended to perform a functional test before installing the assembled kit into the
layout. You will need a light bulb for the function test.
There are terminal strips soldered to the module which are used to insert and screw on the
connecting cables. Connect the bulb to the four inputs of the track busy indicator one after
the other.
Light bulb Connection to: Input E1 and ~ (not ^!) of the GBM-1
GBM-1 ~ and ^Connection to: Transformer
→ Now the lamp and the LED at output A1 should light.
→ Repeat the test for E2, E3 und E4.
Caution:
If a component gets too hot, disconnect the track busy indicator from the mains
immediately. Possible short circuit! Check the assembly again.
After successful completion of the function test, disconnect the track occupancy detector from
the supply voltage again and the light bulb from the input of the GBM.
14 Assembling the kit

tams elektronik GBM-1
4. Connecting the track busy indicator
There are terminal strips soldered to the module which are used to insert and screw on the
connecting cables.
4.1. Pin assignment
GBM-1 Connection to
E1 to E4 Isolated conductors of the monitored rail sections
A1 to A4 Downstream accessories or digital feedback modules
+ Return conductors of the downstream accessories
^ ^ - rail not monitored
^ - or "" connection of the transformer supplying the GBM-1
^ - connection of th driving transformer / booster
Notice: Internally, the two ground connections of the GBM-1 ^ are connected to each other, you can
use them according to your needs.
~ ~ - or "+"- connection of the transformer supplying the GBM-1
4.2. Connections
Isolation of t e conductors
The busy status can only be reported trouble free, when with each monitored section one
conductor is isolated at both ends:
With centre conductor systems: both rails. When cutting the middle conductor instead of
the two rails, it is impossible to connect digital feedback modules directly to the outputs A1
to A4.
With 2-rail systems: one of the two rails.
Connecting the track busy indicator 15

GBM-1 tams elektronik
Connection to alternating current systems (centre conductor systems)
Connection to direct current systems (2- rail systems)
0 Track section without monitoring
1 - 4 Report sections 1 - 4
4 Report section to be switched off (Example)
16 Connecting the track busy indicator

!
!
!
tams elektronik GBM-1
4.3. Connection of the track sections
Connect the isolated conductors of the monitored rail sections to the inputs (E1 to E4) of the
GBM-1.
Monitoring switc ed off track sections
Track sections to be cut off in operation (e.g. in a shadow station) can also be monitored with
the track busy indicator. For that purpose a resistor with a value between 1 kW und 4,7 kW
has to be mounted in the wire leading to the concerned track section so that it shunts the
switch when the track section is cut off (see connection diagrams on previous page,
connection to E4).
4.4. Connection to the voltage supply
Connect the ground connections of the supply transformer for the GBM and the driving
transformer to the ground connection of the track occupancy detector. The two ground
connections of the GBM-1 (^) are internally connected and can be used as required.
Caution:
The GBM-1 must not be supplied by transformers or a digital boosters providing current for
driving operation. In order to supply the GBM-1 you can use transformers or boosters which
supply other track busy indicators or lighting modules as well.
Caution:
If you use a d.c. transformer for the power supply of the GBM-1, you generally have to
respect the polarity when connecting it. If using an a.c. transformer the polarity is of no
importance first.
When connecting several outputs to circuits supplied by the same transformer, all
connections have to be polarized the same way as a rule. Otherwise a short circuit could
occur damaging connected devices.
Caution:
The ground of the driving transformer must not be connected to any of the four track
sections to be monitored, as the busy status could not be reported then.
Connecting the track busy indicator 17

!
GBM-1 tams elektronik
4.5. Connecting lamps or LEDs
Lamps are not polarised, thus the assignment of the connections to the outputs of the GBM-1
(A1 to A4) and to the return conductor for the outputs (+) is optional.
With LEDs you have to observe the polarity, otherwise they do not light. Connect the cathodes
(-) to the outputs of the GBM-1 (A1 bis A4) and the anodes (+) to the return conductor for
the outputs (+). With standard LEDs the longer connecting pin is the anode (+).
Attention:
When using LEDs you always have to connect them via a series resistor as the LED will be
damaged when put into operation or its duration of life will be reduced considerably.
The necessary value of the series resistor depends on the voltage supply to be available, the
forward voltage of the LED (which depends on the colour) and the current.
Calculating the series resistor:
necessary RV [Ohm] = ( UB [V] – UF [V] ) / (IF [mA] x 0,001)
UB = operating voltage
UF = forward voltage of the LED
IF = current with max. luminosity
For red and green LEDs you can take 2 V as a basis for the forward voltage. The luminosity
depends on the current draw, with standard LEDs the difference between 10 and 20 mA is not
visable.
Connection to a.c. voltage
Note: The operating voltage of an a.c. transformer is approx.
1,4 fold the nominal voltage given.
Connection to d.c. voltage
Note: With d.c. Power packs the operating voltage
corresponds to the nominal voltage given.
Nominal
voltage
Necessary series resistor with
current draw
Nominal
voltage
Necessary series resistor with
current draw
10 mA 20 mA 10 mA 20 mA
12 V ~ 1,5 k820 16 V = 1,5 k820 
14V ~ 1,8 k820 18 V = 1,5 k820 
16 V ~ 2,2 k1 k20 V = 1,8 k1 k
18 V ~ 2,2 k1,2 k22 V = 2,2 k1 k
18 Connecting the track busy indicator

tams elektronik GBM-1
5. Connecting subordinate circuits
Consumers with a current consumption of up to 500 mA can be connected directly to the
outputs A1 to A4 of the GBM-1 and switched on and off depending on the occupancy status.
The GBM-1 evaluates the income signals against earth. Thus you can connect the outputs of
the GBM-1 to:
the inputs of downstream electronic circuits that switch to ground and consume a current of
max. 500 mA;
relays to switch the inputs of subordinate electronic circuits with a current consumption of
more than 500 mA or to switch circuits requiring to be galvanically isolated;
relays to switch the current at the outputs of subordinate modules.
5.1. Connection of digital feedback modules
In principle, it is possible to connect the inputs of digital feedback modules (e.g. s88 modules)
to the outputs of the GBM-1.
Due to the high sensitivity of the GBM-1, interference voltages from the digital system can
generate false occupancy messages. Therefore, instead of a GBM-1, the GBM-8 and
GBM-8.2** track occupancy detectors optimised for digital operation are more suitable for use
in combination with digital feedback devices.
5.2. Application example: Block section control
Functional principle
In the block section, the section behind the occupied section (seen in the direction of travel)
must be blocked for the entry of a following vehicle and the section behind it must be released
again.
With track occupancy detectors and one bistable relay (RL) per section, a block section control
can be realised. The relays are connected between the inputs E1...E4 of the GBM and the
corresponding track sections and function as switches for switching the track voltage in the
relevant sections on and off.
The control connections of the relay are controlled via the two outputs of the GBM, which are
assigned to the two sections a ead. If the section ahead is occupied, the relay's normally
open contact is opened and the section is thus de-energised (see track sections 2.1 and 2.3 in
the illustration). If the section ahead is vacant again, the contact of the relay is closed again
and the section is thus supplied with current again (see track section 1.4 and 2.2 of the
illustration). If neither of the two sections ahead is occupied, the contact of the relay remains
closed and the section is supplied with power.
Connecting subordinate circuits 19

GBM-1 tams elektronik
Connection example
For an automatic block section control you need
one GBM- 1 track occupancy detector for up to 4 sections each
one bistable relay or one relay board RL-2 (item numbers 72-00055 or 72-0056) for each
section
20 Connecting subordinate circuits