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HA0364T Rev C Aug 2022
Chapter 6
Triggering Introduction
The K-Cube motor controllers have two bidirectional trigger ports (TRIG1 and TRIG2)
that can be used to read an external logic signal or output a logic level to control
external equipment. Either of them can be independently configured as an input or an
output and the active logic state can be selected High or Low to suit the requirements
of the application. Electrically the ports output 5 Volt logic signals and are designed
to be driven from a 5 Volt logic.
When the port is used in the input mode, the logic levels are TTL compatible, i.e. a
voltage level less than 0.8 Volt will be recognised as a logic LOW and a level greater
than 2.4 Volt as a logic HIGH. The input contains a weak pull-up, so the state of the input
with nothing connected will default to a logic HIGH. The weak pull-up feature allows a
passive device, such as a mechanical switch to be connected directly to the input.
When the port is used as an output it provides a push-pull drive of 5 Volts, with the
maximum current limited to approximately 8 mA. The current limit prevents damage
when the output is accidentally shorted to ground or driven to the opposite logic state
by external circuity.
Warning: do not drive the TRIG ports from any voltage source that can produce an
output in excess of the normal 0 to 5 Volt logic level range. In any case the voltage at
the TRIG ports must be limited to -0.25 to +5.25 Volts.
Input Trigger Modes
When configured as an input, the TRIG ports can be used as a general purpose digital
input, or for triggering a relative, absolute or home move. When used for triggering a
move, the port is edge sensitive. In other words, it has to see a transition from the
inactive to the active logic state (Low->High or High->Low) for the trigger input to be
recognized. For the same reason a sustained logic level will not trigger repeated
moves. The trigger input has to return to its inactive state first in order to start the next
trigger. The mode is set in the
Trig 1 Mode
and
Trig 2 Mode
parameters as follows:
Disabled
- The trigger IO is disabled
Digital Input
- General purpose logic input (read through status bits using the
LLGetStatusBits method).
Trig In Rel. Move
- Input trigger for relative move.
Trig In Abs. Move
- Input trigger for absolute move.
Trig In Home
- Input trigger for home move.
When the trigger mode is selected to
Trig In Rel Move
or
Trig In Abs Move
, the relative
distance or absolute position to move, can be entered in the
Relative Move Dist
and
Absolute Move Pos
. parameters.
