Summer Start with ZIMO Decoder News

For a long time already, many model railroaders consider ZIMO decoders to be the best there is. But even the best has room for improvement. In January we presented a list here of possible new developments (The Features of Tomorrow); in the meantime some were fulfilled (e.g. extended function mapping with CV #61 = 98 or MOTOROLA for large scale) and implemented with new software, some of them are still in development stage; but new ideas were also formed from public discussions and from experience gained in field-tests.

• Further fine-tuning of motor regulation

Smoother motor regulation characteristics for actual motor starts at lowest speed step and for "difficult" motors (with 3 armatures, ....). 

• Km/h - defined speed control as alternative to today's usual method of percent scale graduation.

To interpret DCC speed steps (128 in modern systems and decoders) as absolute speed in km/h or mph -  actually an obvious idea and yet, was only recently taken up in public discussions. The proper setting of the already present CV #5 (top speed) does not bring the desired results. ZIMO puts this idea now into practice with three steps:

A new CV as conversion factor, which takes into account the scale (HO, O, 1 etc.) and length of the calibration track (see below); to be entered with the help of a simple formula.

-During a calibration procedure, the loco is driven at a given speed for a predetermined distance (e.g. 15 feet). Passing the start and end of the line is recorded by activating a function (semi-automatic procedure) or a decoder input (Reed switch or similar for fully automated procedure).

- This kind of control is not just for a visually pleasing drivability, which is the main task of today's load regulation or back-EMF, but rather to hold a desired speed exactly, in km/h or the distance to reach a full stop. This new demand is reached by continually calculating the already driven distance and applying the necessary changes. The required data (EMF values, taken up to 200 times per second) and the processing power is available in all current ZIMO loco decoders.

Using km/h or mph for controlling loco speed adds a number of other operational advantages; from the strict observance of speed limits to the precise calculation of arrival times at the next station. Consist operations should also profit from such precise speed control - although field tests have yet to be performed to confirm this.

The mph speed control is also related to the announced "distance controlled stopping" but is not yet included in this version. 

• Virtual wheel synchronizer for Dietz and other sound modules.

For a loco to sound prototypical (especially a steamer), the sound produced by the decoder has to be synchronized to axle movements. This can be achieved with optical, inductive or magnetic sensors that send the actual position of the wheels to the decoder. Installing such sensors though is often quite difficult and often unreliable (susceptible to dirt). So far, the usual alternative method has been to use the selected speed as the basis for sequencing the single steam chuffs. The result is most often a wrongly assigned sound sequence that can not be overlooked when compared to the actual loco movement (most often, the chuff rate at low speed is much faster than the actual loco speed). 

The "virtual wheel synchronizer" however - a function output of the MX69 decoder - relies on the actual speed as measured through BEMF (resulting in big differences at lower speeds) and is connected to the sound module just like a real wheel synchronizer (in addition to the SUSI interface). Of course, contrary to a real sensor, there will be no synchronization to the actual wheel position but with the speed  properly matched, the goal of synchronized sound (chuff rate) is achieved. 

• Implementation of signal stops with "asymmetrical DCC signal (Lenz ABC).    

Even though the "asymmetrical DCC signal" doesn't offer the flexibility and range of functions the ZIMO "signal controlled speed influence" does, it is nevertheless an alternative method for simple applications. It is possible to have automated directional signal stops with just 4 diodes at the track (at virtually no cost)

Even though the "asymmetrical DCC signal" doesn't offer the flexibility and range of functions the ZIMO "signal controlled speed influence" does, it is nevertheless an alternative method for simple applications. It is possible to have automated directional signal stops with just 4 diodes at the track (at virtually no cost)

• Uninterrupted driving

Insulated frogs or heavily soiled track should not stop a loco; the new decoder software will take care of that automatically. That requires an energy source during power interruptions, which may be in the form of a condenser connected to the decoder (see decoder manual) or the energy modules (MXSPEIK, MXSPEIG) currently in development.