System signals

The functions of all PICS signals are described in this section, but it must not be assumed that all interfaces and controllers support every signal. The installation guide for individual products must be referred to for full details of signals used and their time relationships.

Types of output signal

There are three types of output signal transmitted by PICS:

• STATUS signals
• WARNING signals
• SYNCHRONISATION signals

Status signals

PICS uses the following five STATUS signals:

• Probe power OFF (PPOFF)
• Halt (HALT)
• Probe damping (PDAMP)
• LED off (LEDoff)
• ERROR (ERROR)

Pin 2 - Probe power OFF (PPOFF)

The purpose of setting this status line is to inhibit the probe trigger signal (SYNC) and, in the case of the laser probe, it can also be used to switch off the laser or light source.

An example of the use of this signal is to inhibit a probe during an autochange cycle. In this case, the line is activated by the autochange controller. This line may be set by any Renishaw device or the CMM controller.

Pin 4 - Error (ERROR)

This line is set by the interface if it has determined that the last reading (trigger or measurement) was not reliable. It is intended that this output should be used to tell the CMM control to disregard and, if appropriate, repeat the last reading.

Pin 7 - Probe damping (PDAMP)

Setting this line will reduce the interface sensitivity so that it will ignore any unwanted short probe synchronisation events, such as a probe “trigger” due to vibration or acceleration. If, however, the probe is triggered for a long period, possibly indicating a crash, then SYNC and HALT signals are sent as usual.

This line may be set by any Renishaw device or the CMM control.

Pin 8 - LED off (LEDOFF)

Setting this line turns off the probe head LED and is normally used by interfaces to indicate a probe signal. The line can be set by any device. The LED is only on if none of the PICS devices (including the CMM controller) is applying LEDOFF.

Pin 9 - READ (READ)

This line is activated by the CMM controller to command the interface to take a reading. An example of its use is with the SP600 interface card, the AC2. Setting this line causes the AC2 card to read the current stylus position of the SP600.

For further details, please refer to the appropriate interface documentation.

Warning signals

Pin 1 - STOP (STOP)

This line indicates that an operational error or crash has occurred in either a Renishaw device or the CMM control. The unit setting the STOP line illuminates a RED LED on the front panel.

Renishaw units receiving STOP will react in various ways:

• Interfaces – respond to STOP by forcing their probe outputs to the triggered state irrespective of the probe state
• Autochange controllers – STOP inhibits any movement of the drive blades while it is present. If STOP is applied while the autochange is in the middle of a lock or unlock operation, it aborts the operation and the ACR1 blade will return to the unlock position. Please refer to your autochange system documentation for further explanation.
• Motorised head controllers (PHC10-3 PLUS) – STOP prevents any automatic head movement while it is asserted. If STOP is asserted during an automatic head move, then the power to the drive motors is removed. If STOP is asserted during a manual head move, the PH10 / PH10 PLUS will only move in single steps.

All Renishaw devices assert the PICS STOP signal if power is removed from that device.

On receipt of this signal, the CMM should stop all axis drives immediately.

This line may be set by any Renishaw device or the CMM control.

Synchronisation signals

PICS has a line dedicated to the synchronisation of the probing system with the CMM scales.

Pin 5 - Synchronisation (SYNC)

This line is a dedicated input to the CMM control. When set, it indicates that a synchronisation event has occurred (e.g. a touch-trigger probe “trigger”). This enables the CMM control to read the CMM scales in synchronisation with the probe trigger.

This line is normally only set by a Renishaw interface; it is unidirectional – i.e. it is only output from the Renishaw system.

Types of input signal

This section describes the PICS input connection for a probe interface. The majority of input signals are the same as those described in the ‘Types of output signal' section, with the exception of those listed below.

If more information is required on the function of the PICS input to a probe interface, please refer to the respective probe interface documentation. Alternatively, you may contact Renishaw direct for assistance (please refer to the front cover of this document for contact details).

Un-interfaced probe signal

These pins are used to transmit and receive 2-wire touch-trigger probe signals when a multiwire cable is not in use.

Pin 5 - Probe signal

This line is a dedicated output (supply) from the probe interface to a 2-wire touch-trigger probe.

Pin 9 - Probe signal return

This line is a dedicated probe input (return) to the probe interface from the 2-wire touch-trigger probe.

Other signals

Pin 4 - LED anode

This line is used to supply a probe head with the necessary voltage and current to illuminate the head LED.

Pin 6 - Stop (pull-up)

This line is used when a probe head controller is not fitted to the probing system and, in this case, the interface can supply the ‘pull-up' for the PICS STOP line (pin 1).