Service manual

Avantra 36/44 Service Manual

2-12 Functional Analysis

• Connects directly to all sensors (except several that connect to the CSDM)

and gathers them into matrices of 2 x 6. This allows for a simpler and

more orderly system cabling scheme.

2.7.1 SDM to DEC Interface

Each SDM has one header connection from the DEC, providing power and two 8-

bit data lines for reading sensors and controlling motors. The control signals for

the servo motors also pass through this header to the appropriate servo motor.

2.7.1.1 Motor Drives

The SDM has three basic types of motor drivers:

• Stepper

• DC motor/solenoid

• Servo

2.7.1.2 Sensors

Each SDM supports twelve sensors conﬁgured in a 2 x 6 matrix. The matrix is read

directly by an 8-bit data port through a RS-423 type driver pair to the DEC. The

sensor matrix is similar to that of a keypad design where each sensor has a row and

column location (address) on a grid (refer to Figure 2-5). A sensor is determined to

be active by addressing a column within the grid and reading the row for an active

sensor condition.