Manual

Detailed Descriptions of ACL Commands 3-31
In the case of bits 8 through 11 (PAUSE, STOP, interrupts, and Step Verify): if the button is
pushed (or the event occurs) while disabled by FP then the event is logged ("remembered")
and acted upon as soon as a subsequent FP command re-enables it. While the event is
pending the corresponding front-panel light, if any, glows steadily; i.e., does not blink.
When another FP re-enables the event the light begins to blink.
Thus, FP can be used to protect small critical sections of a move sequence from undesired
interference, as shown in the example below.
In the case of all other buttons (bits 0 through 7 and 12): if the button is pressed and released
while disabled by FP then there is no effect. If the button is pressed while disabled but is
held until after it is re-enabled then its action is performed at that time.
Example: the command FP 96; disables the FAST and GO TO ORIGIN buttons, so the
operator can only move the carriage via the slow Arrow buttons.
Example: suppose your application uses a drill motor or a heater controlled by Digital
Output 0. You execute the following sequence: FP 256; CD 1,1; WA .5; CD 0,1; FP;.
The first FP locks out the PAUSE button. Then the first CD turns on the drill or heater; the
WA waits for a half second; and the second CD turns it back off. The final FP re-enables all
buttons. If the PAUSE button is pushed while the drill or heater is active then the PAUSE
light turns on, but the machine does not actually pause until after the drill motor or heater is
turned off.
FZ [<only if needed>] Find Z Home Switch
The Z axis motor moves in the negative direction until the Z axis home switch closes. This
establishes the Z Home position. The No Z Reference status bit is cleared. (See the OS
command.)
The <only if needed> parameter is optional. If it is specified and is nonzero then the
System checks the No Z Reference status bit before performing any motion. (See the OS
command.) If the switch has already been found (i.e. the status bit is zero) then the FZ
command performs no motion.
If <only if needed> is omitted it defaults to zero; i.e., the motion is performed regardless of
the No Z Reference bit.
The FZ command actually finds the Z home switch twice -- once at high speed and a second
time at low speed for greater accuracy. The motor backs away 100 steps before seeking the
switch the second time.
In order to provide greater load-carrying capacity in systems where the Z motor must fight
gravity to reach the home switch, the FZ command uses a smooth acceleration at startup
rather than instantly jumping to the full seek speed. However, when the switch closes the
motor stops instantly.
The values of acceleration, seek speed, and back off distance can be changed via personality
parameters 52 through 56; see Chapter 7. The half/full-step mode is as specified in the CZ
command or personality parameter 46.