SMD82 - Switch Machine Driver

The SMD82 is an eight (8) output DCC accessory decoder (HO & N scale) specially suited to drive switch (turnout) machines. It features 13 local inputs and 16 routes including conditional routes.

MSRP - 89.95 USD
Manual in PDF format

Board size: 2.75" X 4.25"

The SMD82 is capable of driving eight solenoid and/or stall motor type switch machines. It contains a Capacitor Discharge Unit to store energy. A discharge of this energy is used to energize the solenoid to change the switch state. Using a CDU reduces the current drawn from the track to a small level sufficient to recharge the CDU. However, once the CDU has been discharged (a switch state changed) a time period is required for the CDU to recharge. This is typically about three seconds. Since more than one switch may be requested to change state at the same time, as in a local route, the requests are held so that each switch may change state in turn. A stall motor type does not use the CDU and therefore, no recharge time is required when activated.

There are four output configurations: short pulse for solenoid type machines, continually on for stall motor type machines, eight second pulse (variable) for stall motor type machines where reduced track current is desired and manual control.

The eight outputs of the SMD82 can individually be assigned any address from 1 to 2040. There are 13 inputs available for local control. An addition eight inputs are available with the use of some resistors.

Two types of route control are supported. The remote controlled routes are controlled from the throttle just like a single switch is, except that multiple switches may be activated. The local routes are activated by using the inputs. Routes are configured by programming the respective CVs as to which outputs are selected in the route and the output state. Remote controlled routes are in two groups of eight. Each group has a group address to allow the throttle to access it.

Conditional routes can be established so that an input can not activate it's route unless another input is activated.

“Smart” programming is a term used to describe a method to program Configuration Variables (CVs) using switch addresses. This method is a much easier way to program CVs. With “Smart” programming, you can set the output addresses and the output configuration for solenoid or stall type switch machines.

For route and custom setup, the SMD82 supports Paged Mode Programming in Service Mode and Ops Mode. Ops mode programming is very convenient because you can try out the CV changes almost immediately. "Power on" Ops mode is an additional temporary mode that provides a very quick method of programming CVs.

The SMD82 has been specifically tested with the Digitrax DCS 50 and DB 100 systems and the NCE Powerhouse Pro system.

smd82 diagram