Sig-naTrak -

DAC 22 Accessory Decoder

It allows control of up to 8 point motors, or 16 “on/off” accessories (e.g. lights) on a DCC controlled model railway layout.

Improvements over the original DAC20 include:

• Traditional “leaded” components are replaced with modern surface-mounted parts, for enhanced ruggedness and reliability.
• The majority of components are now enclosed to help prevent inadvertent short-circuits and/or the ingress of debris.
• The DAC22 will drive virtually any type or brand of point motor – e.g. solenoids, or “Tortoise” style slow-motion units – without the requirement for output adaptors or an auxiliary power supply.
• When using solenoid point motors, an internal voltage boost circuit guarantees a 20volt supply to the capaci
• When using solenoid point motors, an internal voltage boost circuit guarantees a 20volt supply to the capacitor discharge unit (CDU) thus providing a strong pulse for reliable operation.
• Output addresses are no longer restricted to a sequential contiguous block of 8 (or 16). Each output address can, if desired, be individually set to any address within the range of 1 to 2043.The DAC22 also has provision for local switches and LEDs for manual operation & status indication.

Its switch inputs can also be used for position feedback or as sensor inputs, using LocoNet to report status to the central command station.

• The DAC22 supports simple programming of logical conditions. These conditions can cause the output to change according to events, or stop the output from changing. These can be used for:
• Controlling semaphore signals in response to point settings and track occupancy.
  
  (The DAC22 can also generate the same signalling message a sthe SIGM20, to allow mixed semaphore and colour light signals).
• Controlling crossing gates, when track onto a crossing is occupied by a train.
• Preventing a "three way" point or single slip from being put into an "illegal" state.

The DAC22 supports enhanced local routes. Local routes can be triggered by local inputs, by DCC accessory commands or by logic conditions. Local routes can trigger points on other accessory deciders, as well as those driven by the same DAC22.

The DAC22 supports several programming options, with the programming track method available as a last resort. Simplified programming options include:-

• Using our PC program "Locoanalyse". Settings can be edited on the PC and be saved to a file. They can download to the board through "live" LocoNet if you have a LocoBuffer or DigiTrax PR3 module.
• Using a "learn address" mode. By setting a single DCC accessory output, the unit can program the base address and set all outputs for Tortoise or Solenoid point motors.
• Using "on the main" ops mode programming.
• On a programming track, for diehard enthusiasts!

The DAC22 has a full function LocoNet interface. It can generate LocoNet messages - for example sensor messages, point position reporting messages and signal control messages. It can respond to LocoNet messages: for example allowing outputs to be triggered by track occupancy sensor messages. The DAC22 can also report the position of points from the stored state WITHOUT needing feedback microswitches attached to tiebars: so PC programs such as Railroad & Co's "Traincontroller" will know the point positions after a "track power on" command.