VICI Selectors (multiposition) Standard electric - Manual (Page 6)

 Controlling the Actuator with a Computer
Random Access
Logic Input
For devices with an RS-232 connector, a simple solution is available in the
form of the Valco Serial Valve Interface (SVI). The SVI is a self-contained
unit, complete with software, that will convert commands from a computer
into positional control for as many as two multiposition and four two position
Valco electric actuators. Designing a similar means of control for a computer
without a serial port requires a little more thought and effort on the part of
the user.
Refer to Drawing 21464 on page 18 to determine the functions of the wires
in the interface cable. All of the inputs are held at five volts, called “logic
high”. When they are pulled to ground potential (“logic low”), the voltage
drop signals the logic circuits in the actuator to direct the motor to the
appropriate point. Randomly accessing the positions involves two steps:
first, a logic low signal must be applied to the proper BCD input lines to tell
the actuator which position to go to; then, a logic low signal must be applied
to the enable line, telling the motor to turn on and find the specified position.
Locate the inputs which are labelled 1’s, 2’s, 4’s, 8’s, and 10’s, plus
PRESET ENABLE and GROUND. Strip a small amount of insulation from
each of these wires. To demonstrate the two steps described in the previous
paragraph, first touch the brown wire (1’s) to the white wire (ground), loading
the code for Position 1. Then, while the brown and white wires are still in
contact, touch the green wire (PRESET ENABLE) to the white wire (ground)
to execute the move to Position 1.
Position 2, 4, 8, and 10 are just as straightforward, but the other positions
involve combinations of two or three wires. To load the code for Position 3,
twist the 1’s and 2’s wires together and touch them to ground. For Position 5,
twist together the 4’s and the 1’s. A complete table appears below.
Position BCD Combination
1 1’s
2 2’s
3 1’s + 2’s
4 4’s
5 4’s + 1’s
6 4’s + 2’s
7 4’s + 2’s + 1’s
8 8’s
9 8’s + 1’s
10 10’s
11 10’s + 1’s
12 10’s + 2’s
13 10’s + 2’s + 1’s
14 10’s + 4’s
15 10’s + 4’s + 1’s
16 10’s + 4’s + 2’s