Märklin Digital
Märklin Digital is the name of a system for digital model railway control that the model railway company Märklin brought onto the market in 1984. It was the first generally available digital model railway system.
Principle function
Classic model railway controls use two conductors in the model railway track, between which a voltage is applied. The conductors are directly connected to the motor in the model locomotive, which rotates at a speed proportional to the voltage and moves the locomotive. This technology is now called " analog ".
A digital model railway, on the other hand, uses the two conductors in the model railway track as a combined energy-data bus , which provides a constant voltage as an energy supply, into which additional control commands are woven. These commands are evaluated by simple and small microcontrollers in the locomotives, the so-called " decoders ". Additional permanently installed decoders also enable the control of stationary devices such as switches or signals .
Marklin Digital used initially to drive the bus and for decoding the embedded control commands integrated circuits from Motorola , is why in the original system and the Motorola format or the Marklin Motorola digital system speaks. From 2004 this type of control was supplemented by the mfx system, which is described in more detail in the Märklin Systems article . Both systems were developed as house standards for the Märklin company. This is a fundamental differentiator to alternative digital model railway controls , in which the digital command control data format (also known as DCC) has established itself on a broad front. In the classic Märklin digital system, the data bus is unidirectional, i.e. This means that the locomotives and other devices can only receive commands from the control center, but cannot send any information themselves. The system uses a second, completely independent feedback bus for this purpose . mfx decoders, on the other hand, have a built-in feedback capability, which means that appropriately equipped vehicles register automatically with the control center. All mfx decoders also understand the Motorola protocol.
A square-wave voltage that oscillates between +22 V and −22 V is fed into the Märklin digital bus for power supply . This is based on the classic Märklin system, which works with an alternating voltage of up to 16 V in the track to control the motor. For this reason, locomotives that are theoretically not equipped with a digital decoder can also be used on a Märklin digital model railroad - they always move in the same direction at a constant speed.
With the Märklin-Motorola protocol, the digital information is transmitted on the bus in that the time span for positive and negative voltage between the conductors is not exactly the same. A digital 0 or 1 is transmitted depending on whether the transition between positive and negative voltage occurs a little earlier or later than necessary for a uniform frequency. A digitally transmitted command is created via the protocol layers of the Motorola format.
In addition to controlling the locomotive decoders, the Märklin-Motorola protocol uses a practically identical data format for controlling turnout and function decoders, but uses a clock with twice the data rate, so that both types of decoder ignore the signals of the other type.
System components
Original components of the central control
The heart of the first Märklin digital system is the central unit , which drives the data bus and sends commands. In its original design it has no operating elements and at least had to be supplemented by a Control 80 and a transformer. The control 80 is used to enter the control commands for the locomotives. Over time, various combinations of these three components came onto the market.
On the Control Unit, a combination of Central Unit and Control 80f, the locomotive to be controlled is selected using a ten-digit keypad; the speed can then be changed with a rotary knob or a special function can be switched on and off using additional function keys - such as lights, a sound module or a steam generator. Early versions of the Märklin digital system only allowed one such special function. Up to four functions were added later. In principle it is always possible to use several Control 80 and / or Control 80f to control several locomotives at the same time.
In addition, so-called keyboard units can be connected to the central unit , each of which can switch up to 16 stationary command receivers such as switches and signals. In contrast to the Control 80, a receiver is permanently assigned to each pair of buttons. In order to switch more than 16 receivers, several keyboards can be integrated into the system.
The central components are supplemented by a kind of intelligent keyboard called memory , which enables routes to be saved, and an interface module, which establishes a connection to the serial interface of a computer.
All these components are connected to one another by a common data bus ( I²C bus ). The central unit implements the commands coming from the various input devices and sends them to the command receivers via the tracks or supply lines laid parallel to them. If necessary, the entire system must be broken down into several circuits so that the total power consumption per circuit does not become too great. Each circuit is connected to the Central Unit via a digital amplifier called a booster .
The classic Märklin digital system allows 80 locomotives and 256 fixed receivers to be controlled via the same data bus.
Alternatively, the computer itself can be used as a control center, e.g. B. with the software Digital Direct for Linux or Rocrail . All that is needed from the Märklin range is a transformer and a booster.
Märklin Delta / Märklin My World / Märklin Start Up
As a result of the further developments in the manufacture of electronic components and assemblies, electronic controls for locomotives became cheaper to manufacture from around 1995 than the parallel offering of analog and digital models that had been operated up until then.
For this reason there was an early approach with the system called "Märklin Delta" to offer digital controls also in the entry-level segment. In contrast to two-wire DC systems, Märklin always had a separate control system in the form of a changeover relay in the locomotive due to AC operation. The Delta system uses the same command format, but dispenses with the control of stationary receivers and can only address a maximum of 15 different locomotives. There are even more reduced controls for starter sets, which are limited to four different locomotives (declared as "steam locomotive", "electric locomotive", "diesel locomotive" and "railcar"). As a saving measure, simple controls only have push buttons for “slower”, “faster” and “change of direction”. The power is partially limited to less than 20 watts.
From 2012 the Märklin My World brand , from 2014 Märklin Start Up, was used for this simple type of digital control. Confusingly, the kits that were added as battery trains in H0 in 2012 were then continued as Märklin My World from 2014 .
Receiver (decoder) and transmitter
There are basically three different types of decoders:
- Decoder for controlling engines and functions in locomotives.
- Decoder for switching functions such as controlling turnouts and signals.
- Special receivers and transmitters, for example, for controlling special equipment such as cranes or for feedback.
Receiver (decoder) for locomotives
The decoders built into the locomotives take over the internal control of motors and functions. The necessary strong miniaturization due to limited space was the decisive development step towards the digital model railway. The Märklin system in particular benefited from the fact that the classic Märklin locomotives still required a second component in the locomotive in addition to the motor, the changeover relay for changing the direction of travel, so that space could always be gained inside the locomotive by removing the changeover switch . Instead of the switch, the decoder was installed. The first generation of digital Märklin locomotives was further developed from their non-digital counterparts in many models through this one change. Even the self-conversion of existing locomotives was comparatively easy for the experienced do-it-yourselfer.
In the history of the Märklin digital system there have been different types of decoders that could address different types of motors or different additional functions. Since the locomotive motor is decoupled from the supply voltage with the digital decoder , completely new motor types could also be used, for example brushless motors such as the C-Sinus high-performance drive . Initially, only a single additional function was supported (mostly switching lights), soon there were up to five, including acceleration and braking delay; Today's decoders also support sound and the control of brushless motors.
The decoder is designed so that a locomotive equipped with it can also be used on analogue-controlled systems. This also applies to the simplified version, the decoder of the Delta system . The vast majority of Märklin locomotives are therefore now always delivered with a decoder. Almost all older models can be converted to control with digital commands using kits. While older decoders have to be explicitly set to analog operation by a reserved address, newer decoders automatically recognize operation with alternating voltage, today even with direct voltage, and adjust the control of the motor accordingly.
All Märklin digital and Delta system decoders are technically designed for 80 addresses. With the Märklin digital decoders it is also possible to use the 80 addresses, but only 15 addresses can be used with the simplified decoders for the Delta system.
Since the addresses are technically not sent as binary numbers in the data stream of the Motorola protocol, but rather as trinary values packed in "trits" (two binary values encode only three defined states), it was possible to expand the protocol instead of 81 to 255 different addresses to send on the bus. This is partly supported by newer decoders and controls, while older decoders are limited to the original addresses.
Decoder for the Delta system
Probably in order to replace the tricky switchover relay and to supplement the digital system, which was expensive for the time, with an inexpensive system, simplified decoders for the Delta system were produced since 1992. This decoder for the Delta system is upwardly compatible, i.e. it can be used without restriction on both the Märklin digital system and the Märklin system . This decoder also replaced the electronic direction switch that was just emerging at the time. To make this decoder more cost-effective than the Märklin digital system, the DIP switches were initially left out; the address had to be determined by solder bridges. This generation was very quickly replaced by a decoder with four instead of the eight DIP switches customary in the Märklin digital system, which resulted in the limitation to 15 addresses. As a rule, they also have no way of switching additional functions.
| address | symbol | 1 | 2 | 3 | 4th |
|---|---|---|---|---|---|
| 02 | - | 2 | 3 | 4th | |
| 06 | 1 | - | 3 | 4th | |
| 08 | - | - | 3 | 4th | |
| 18th | 1 | 2 | - | 4th | |
| 20th | - | 2 | - | 4th | |
| 24 | Electric locomotive | 1 | - | - | 4th |
| 26th | - | - | - | 4th | |
| 54 | 1 | 2 | 3 | - | |
| 56 | - | 2 | 3 | - | |
| 60 | Rail bus | 1 | - | 3 | - |
| 62 | - | - | 3 | - | |
| 72 | Diesel locomotive | 1 | 2 | - | - |
| 74 | - | 2 | - | - | |
| 78 | Steam locomotive | 1 | - | - | - |
| 80 | Hand controller b | 1 | 2 | 3 | 4th |
| Conventional c | - | - | - | - |
mfx decoder
With Märklin Systems, a new generation of decoders was presented in 2004. These mfx decoders no longer have fixed addresses, but are assigned by the control center when they register. The user does not have to worry about address conflicts. A locomotive is placed on the track, registered and can be used. The limit of a maximum of 80 locomotives in the previous system has also been overcome. In order to use these new decoders on previous Märklin digital systems, they also allow the address to be set manually.
Receiver (decoder) for switching functions
There are also special decoder modules for controlling switches and signals, which are also connected to the track or its data bus and can control up to four switches and signals (also known as K83 decoders). Another type of decoder is intended for the permanent switching of permanent consumers such as lamps and the like (also known as K84 decoders).
Feedback decoder
The feedback from track contacts or other sensors is collected in another type of decoder ( feedback decoder S88 ), which can process up to 16 input signals. This is not connected to the track data bus, but directly to the data bus of the control center. Depending on the central unit, up to 63 of these decoders can be connected in series.
Special receivers and transmitters
In the course of time, various special designs have come onto the market. In addition to special modules for digitally controlling the Märklin model crane or the turntable , these are in particular specially shaped turnout decoders that can be built directly into the turnout. There they are supplied with power and data via the track. No additional cabling is required.
Historical classification
Before the introduction of the Märklin digital system, it would have been technically possible to have two trains (with catenary four trains) run simultaneously on the Märklin track by connecting diodes so that one locomotive on the positive half-wave and the other Locomotive runs on the negative half-wave. In contrast to the companies Trix ( Trix ems in the range from 1973) and Jouef ( Jouefmatic 1968 to 1981 in the catalog), Märklin did not support such an analog multi-train control.
The Jouefmatic multi-train control system, which is actually only known in France, enabled the independent operation of up to eight locomotives in addition to permanent train lighting. The data were modulated onto an alternating voltage and received by the decoder, each tuned to a specific frequency.
In general, Märklin Digital is seen as a significant advance in model railroad technology. For the first time, it enabled the independence of many locomotives and switching functions (locomotive lighting, signals, points, etc.) in a single circuit. Control buses for stationary devices or feedback buses have been on the market for a long time, even with the option of computer connection.
The electronic engine control was nothing fundamentally new either. External suppliers had corresponding conversion kits, especially for Märklin locomotives, in their range since the early 1980s. With the 6600 control unit, Märklin itself offered a system that enabled locomotives to be controlled conveniently using electronics.
The original Märklin digital system also has some limitations compared to other control systems that came onto the market only a little later. In addition to the relatively small number of 80 independently addressable locomotives, this is primarily the small number of only 14 speed steps that can be sent to the locomotives. In addition, the system is based on the classic Märklin system when transmitting the directional information. There, the direction relay in the locomotive was addressed by a high voltage pulse and the direction of travel was changed; in the digital system, this task is performed by a special command (speed step 1 - the motor is only supplied with power from speed step 2). As a result, it is not readily possible to clearly specify the direction of travel of a locomotive, which can be problematic in particular with computer controls.
After all, Märklin Digital did not initially offer any simulation functions such as digitally simulated acceleration or braking delay . As long as the control was not carried out by computer, movements of the speed sensor were converted directly to the locomotive speed - as with the classic, voltage-based control. The aforementioned analog control unit 6600 continued here, which has a switchable delay (separately adjustable for acceleration and deceleration).
In the years and decades that followed, Märklin gradually reduced or lifted the system's limitations, whereby, remarkably, extensive compatibility between old and newer system components was maintained.
At the end of 2004, Märklin launched a new generation of control units under the new name Märklin Systems (“mfx” for short), which combines these further developments and offers further innovations.
Even before the introduction of digital model railway controls, products from market leader Märklin were incompatible with other model railway systems due to the central conductor track system in the H0 gauge . With Märklin-Digital, the company continued to consistently rely on its own system and thus secured its market.
With the second generation of mfx control units from Märklin (CS2 and MS2), the DCC protocol is also supported. As already known from other manufacturers, these multi-system controls alternately send data packets from all digital systems used to the track power supply. This trick is based on the fact that the wrong-format data packets are ignored by the decoders.
Influences on Arnold Digital
After the appearance of Märklin Digital, the manufacturer Arnold from Nuremberg developed its own digital multi-train control for its two-wire DC-N range, although it cooperated with Märklin: the HAMO DC digital system developed by Märklin and that of Lenz Electronics was used was developed for Märklin. The system is basically related to the DCC standard later developed by Lenz, so you can run old Hamo-Digital and Arnold-Digital locomotives on DCC systems.
The Arnold-Digital-Dystem appeared in 1988. Due to the cooperation with Märklin, some control components from Arnold Digital are compatible with Märklin Digital and can partly be used together in one system. The control components of the two systems are also very similar in appearance.
Individual evidence
- ↑ www.Arnold-Digital.com ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. - unofficial Arnold Digital website
