Snack - Based Troubleshooting and Repair Guide
September, 2002 Page 13 of 54 1670065
c. Because a vend cycle is determined by one complete revolution of a snack motor, the
machine must have a method of determining whether or not the motor has made that
revolution (ending back in the “home” position). This is done through a series of two
Cycle Sense lines. As with the Row lines, the Cycle Sense lines are organized in
“odd’ and “even”.
The following example is the sequence of events which occur after an even num-
bered selection (0) is made. Figure 2 is the motor circuit showing the cycle switch in
the closed position. Figure 3 shows the identical circuit with the cycle switch in the
open position.
The controller applies a ground (0 vdc) to the Row 0 Even line. This ground passes
through two resistors and two diodes and is sent back to the controller. Both Cycle
Sense lines (Cycle 1 Odd and Cycle 0 Even) are considered to be ON, telling the con-
troller that the motor (and therefore the tray) is present. The ground is also applied to
the motor, but since +24 vdc power is not yet present, the motor does not turn.
Once the controller has verified the motor is present, +24 vdc is applied to the proper
Column line, powering the motor, which begins turning. At the same time, +24 vdc
also passes through two diodes at the motor assembly, through the cycle switch
(closed, because the motor is still in home position) and to the diodes on the tray con-
nector. The +24 vdc reverse biases the two diodes, removing the grounds from the
controller (turning the Cycle Sense lines OFF). Turning Cycle 1 Odd OFF tells the
controller that the motor is still present. Turning Cycle 0 Even OFF tells the controller
that the motor is still in the home position.
Figure 1 Figure 2
To Next Page
Loading...
Need help?
General
