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PROBE MOVES
Single and double touch (continued)
With some types of controllers, it is an advantage to use the two touch method. The first move finds
the surface quickly. Then the probe is reversed to a position clear of the surface, before making the
second touch at a slower feed rate, thereby recording the surface position at a higher resolution.
Gauging speed
Gauging speeds are not limited by the transmission system delay, which has a repeatability of less than
2 µs. System delays are constant for each direction measurement is taken. These delays are
automatically cancelled out and need not be taken into account, provided a datum move is made in
the same direction and velocity as each measurement move.
Signal delay times
1. Error signal delay
A delay of 48 ms maximum for the OMM + MI 12 or 41 ms maximum for the OMI, will elapse
between an error occurring and the output indicating error.
2. Probe signal delay
The speeds will be limited by the ability of the machine tool control system to process the
probe interface signal, and bring the machine to a halt within the probe overtravel limits.
There is a nominal delay of 140 µs with a repeatability of 2 µs for each interface, from the time the
probe actually operates to the MI 12/OMI interface indicating a probe change of state.
Enabling the enhanced trigger circuit will add a further nominal 7 milliseconds.
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