StudioTech M45-00151 manual Configuration, Initial Operation

drop can become appreciable in situations where belt pack operation wouldn’t nor- mally be impacted. Performing accurate calculations in this scenario is a bit more difficult but might be required to ensure a reliable installation.

Initial Operation

As soon as a source of power is applied the Model 45 will begin its power-up sequence. As a “boot-up” indication the input power, status, and meter LEDs will light, one at a time, in a “walk-through” sequence. After the sequence has com- pleted, one of the input power LEDs will light indicating which power source is actively powering the unit. The Model 45 is now fully functional.

Configuration

To support the needs of various applica- tions the Model 45 allows a number of operating parameters to be configured. A 5-position DIP switch assembly, located on the front panel, is used to establish the desired configuration. Refer to Figure 6 for detailed views.

Using the Connected 2-Wire

Party-Line Circuit as the

Model 45’s Power Source

Configuration DIP switch 1 is used to select whether or not the connected 2-wire intercom circuit can be used to provide power for the Model 45. When the switch is in its off (down) position the intercom circuit cannot be used to power the Model

45.This ensures that no current will be drawn from the intercom circuit, some- thing that can be important if the circuit is limited in available current, or if the length of the interconnecting cable is excessive. When switch 1 is in its on (up) position the 2-wire party-line circuit can serve as the power source for the Model 45.

It’s important to remember that if an ex- ternal source of 24 volts DC is connected it will always be used as the Model 45’s power source. Even if switch 1 is in its on (up) position, power will be drawn from the connected intercom circuit only if the external source of 24 volts DC is not present. With that in mind, it’s highly recommended that unless the application has been carefully designed, any time an

Figure 6. Details of front panel showing the five configuration DIP switches and the configuration switches chart

Issue Preliminary 2, March 2009	Model 45 User Guide
Page 16	Studio Technologies, Inc.