USA57 Revision
1.2
103
Appendix J
Jog Modes and Limit Switches
Jog
The Accuriss can be placed in a mode that will allow the two switch inputs to “Jog” the motor
backwards and forwards. The command for this is
/1n4R
. Once issued, the motor can be moved
by pressing switch 1 or 2. Internally these inputs are “pulled up” with 10K ohms to 3.3V. A
closure to ground is all that is required.
Note that these are inputs 1 and 2, and that the status of the switches can be read via firmware
by
/1?4
. This command returns a binary number between 0-15, which represents the status of
the four inputs.
Limit Modes
The Accuriss uses the two opto inputs as limits. These are inputs 3 and 4. It should be noted
that these inputs are general-purpose inputs and can be driven by switch closures or any device
that produces a voltage change. The inputs are actually ADC inputs, and the One/Zero
threshold can be set by the “
at
” command.
Input 3 is the lower limit and also the home switch. Input 4 is the upper limit. Both limits are
simultaneously turned on by the
/1n2R
command.
The default setting of the Accuriss expects the optos to be low when not on the limit. This
polarity can be changed by issuing a
/1f1R
command, for example when normally open
switches are used for limits. (NOTE: normally closed switches are better for limits, since any
disconnect of the wires will shut down the motion). When n2 mode is engaged, the motor will
not move in the direction in which a limit is active, but will back out of the limit.
In V 6.998 and later firmware, the limits can be moved to the switch inputs 1, 2 if desired by
issuing the command
/1an16384R
.
Note that limit switches can be used to kill moves. For example, a
/1n2gA100000A0GR
command
will loop between
A100000
and
A0,
but if the positive limit is cut during the
A100000
motion, then that command is terminated and the
A0
command is executed.
Noise Considerations
The inputs are relatively high impedance at 10K ohms and will pick up noise if bundled with the
motor wires, etc. For long cable runs, each input line should be shielded. The addition of a
0.1
μ
F ceramic capacitor from the input to ground at the board connector may be an alternative
to shielding, but may slow the response.