VICI Selectors (multiposition) Standard electric - Manual (Page 7)

 Controlling the Actuator with a Computer
To implement the BCD logic, attach the remote cable wires for the PRESET
ENABLE, 1’s, 2’s, etc. to relays or transistor collectors. The white GROUND
wire must go to a “common” point on the control device. (However, direct
connection to open collector transistor outputs may not be suitable in all
environments – the use of opto-isolators may be required. If in doubt,
consult an electronics design expert.) Software must then be created which
will control the appropriate inputs in accordance with the timing diagram
shown in
Figure 4. The direct BCD position inputs (DI1- for for BCD1’s
through DI10- for BCD10’s) must be valid before the PRESET ENABLE
pulse (DIPE-) goes low, and should remain valid for the period, td (1.6 milli-
seconds minimum), after DIPE- goes low. The enabling pulse, DIPE-, should
remain low for the period, tp (5 microseconds minimum). When the STEP
(DIS-) or HOME (DIH-) input is used, it must be held low for the period, ts
(200 milliseconds minimum), to be recognized as valid. (STEP and HOME
operation may be effected with pulses as short as 50 milliseconds, but it is
not guaranteed.)
Logic Output
Some computers have actual BCD logic inputs and outputs, by which the
combinations indicated in the table on the previous page are generated by
the software. This allows a relatively straightforward setup, but matching
the logic sense between the actuator and computer is critical. The input
and output of the actuator are low-true, as supplied from the factory. If the
computer to be used requires a positive true logic (consult the manual for
the computer or interface board being used), the BCD output of the actuator
may be reversed by following these steps to change one of the integrated
circuits:
1. Unplug the actuator. Remove the four 4-40 x 1/4" phillips head screws
which secure the cover to the actuator assembly, and remove the cover
from the body of the actuator assembly.
2. Remove the four 4-40 x 1/4" phillips head screws from the rear cover,
which allows the removal of the PC board inside the cover.
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