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Appendix 1 - Probe signals

It is strongly recommended that the Renishaw AC2 card is used to interface the SP600M probe. However, should you wish to attempt to power the probe and deal with its outputs by your own means, the following information is necessary.

Grounding arrangement

The SP600M has two 0 V connections, 0 V-power and 0 V-reference. It is recommended that they are connected to a star point in the interface and kept separate from the probe screen as shown below. The 0 V-power is used to power the internal circuitry and transducers. The 0 V-reference is a signal from which the outputs are referenced.

sp600_grounding

Screening

It is recommended that the screening arrangements are based on the Faraday cage principle, i.e. the screen is continuous throughout the system. The SP600M connector shell is connected to the body of the probe.

Power supply filtering

The power supply to the probe should be filtered as close to the interface output connector as possible to reduce the output noise to <20 mV RMS in the frequency range 0-7 KHz.

Measurement signal filtering

The input bandwidth is 700 Hz. The measurement signals should be filtered as close to the interface connector as possible to stop high frequency noise getting into the interface. It is recommended that a first order filter with a 3 dB cut-off frequency of ~700 Hz is used.

Cable terminations

The probe cable terminates at the high-density 'D' plug and carries the following signals:


HDD pin no.

Wire colour

Signal description

Signal type

11

Orange

X

Analogue signal

4

Violet

Y

Analogue signal

5

Yellow

Z

Analogue signal

6

Red

+ 12 V

Power output

7

Blue

- 12 V

Power output

12

Blue / white

0 V-reference

Power output

1

Brown

+5 V

Power output

3

Green

0 V-power

Power output

10

Coax inner

O/T 1

Signal output (not used)

8

White

Probe identification

Output

14

Black / white

Head LED anode

-

15

Brown / white

Head LED cathode

-

Shell

-

Screen

Grounding


Total number of connections = 13

sp600_cable_terminations