Renishaw PI 7-2, Руководство по установке

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2 Product description
2. Technical description
The PI 7-2 automatically recognises the probe type, determines the probe status, which
is either triggered or seated (armed), and transmits debounced signals to the CMM
controller. Status and control signals are transferred between the PI 7-2 interface, other
Renishaw equipment and the CMM controller via the product interconnection system
(PICS) ports.
The TP7M probe series employ silicon strain sensors to detect the small gauging forces
applied to the stylus tip. There is no electronic processing in the probe and the sensors
are connected directly to the interface via the Renishaw autojoint connector, the probe
head and associated wiring. The sensor signals are amplified and the resultant ‘probe
signals’, proportional to changes of strain, are compared with reference voltages to
determine the status of the probe.
The initial value of strain in the sensor structure will vary with the mass of the stylus and
the orientation of the probe. At switch-on or following re-orientation of the probe on a
movable head, a process known as ‘autozero’ is used to rapidly null the strain to a zero
reference level.
When the stylus contacts the workpiece, a change of strain occurs in the probe
structure causing the probe signal voltage to exceed the trigger reference level. A
probe trigger signal condition occurs by asserting SYNC on the PICS port. As stylus
deflection increases, the probe signal voltage will exceed the halt reference level and
HALT will be asserted on the PICS port. When the stylus backs-off the workpiece, the
probe signal falls below the reference levels; SYNC and HALT are cleared to the seated
state and the sensor outputs are nulled to the zero reference level in preparation for
the next trigger. Debounce timers allow the motion characteristics to stabilise after the
initial trigger and reseat events, to prevent spurious switching.
A solid state relay (SSR) equivalent of the SYNC output is provided for controllers
requiring a voltage free contact at their probe input.
There is a choice of 2 levels of trigger sensitivity to allow the TP7M series to be used on
a wide range of CMM types or in situations where the ambient vibration levels are not
ideal.
Product description