Manual

Using the Digital Outputs and Inputs 8-3
2. The move sequence can be delayed until a particular condition occurs, by using the WN
("Wait For Digital Inputs") command.
3. You can execute one of two Download Sequences depending on whether a certain
condition does or does not exist on the Digital Inputs; this is the XI ("Execute If")
command.
4. You can repeat a Download Sequence until the Digital Inputs are in a certain state; this is
XU ("Execute Until").
5. You can repeat a Download Sequence while a certain state exists on the Digital Inputs; this
is XW ("Execute While").
6. A certain state of the Digital Inputs can cause automatic actions to occur during vectors,
arcs, Continuous Path moves, or Z moves; this is set up by MN ("Mid-move Digital Inputs
Response").
7. A transition on one of the Digital Inputs can toggle the state of a Digital Output.
8. A transition on one of the Digital Inputs can invoke a Download Sequence as an interrupt.
Logic Sense and Debounce
The logic sense of the Digital Inputs can be changed to be either High True or Low True; see
personality parameter 38 in Chapter 7. This logic sense applies equally to all eight ways of
using the Digital Inputs. For example, the command WN 1,1; waits for a True on Input 0,
regardless of whether the True is to be represented by a high voltage or a low voltage.
Note: the following discussion about debouncing does not apply to the automatic mid-move
responses set up by the MN command. See MN.
The Automove System contains two microprocessors: an Input/Output processor (IOP) for
receiving and processing characters from the host computer, and a vector generator
processor (VGP) for controlling the motors and the front panel. For purposes of toggling
Digital Outputs or invoking Download Sequences the Digital Inputs are polled (i.e.
periodically checked) by the VGP when it isn't busy generating motion or responding to a
front panel button.
Consequently, if a Digital Input changes during a vector, arc, Continuous Path move, or WA
wait, the VGP will not see the change until after the motion or the wait is complete. Also, if
an Input changes from one state to the other and back during a move, the entire pulse will be
missed. Thus you must be sure that your electrical signals remain valid long enough to be
seen by the VGP. If things happen too quickly in your application, you may have to add
external logic circuitry.
The VGP processes the inputs so as to remove the effects of switch contact bounce. The
debouncing is performed as follows: First, the logic sense is evaluated as prescribed by
personality parameter 38. Then the signals are analyzed in the following way. If an Input
was False and is now seen to be True, it is immediately declared True. It is not declared
False until it has been seen to be uninterruptedly False for a period of approximately 20
milliseconds (0.020 seconds).