Renishaw HS20 Installation Manual page 33

Cable preparation
Note: For cable lengths in excess of 10m it is suggested that the 'spare core' in the cable be used to
connect an additional 0V line. This provides two lines for the 0v and can help offset voltage drop on
longer length cables. For lengths over 30m it may be necessary to use cable with 20AWG conductors
for the power lines.
The cabling for the laser head is a critical component in terms of the performance of the installation.
This is primarily because of the harsh electrical environment around most machine tools, and also
the high frequency nature of the signals used in the system. EMC (Electro Magnetic Compatibility)
is very important, and Renishaw have done a considerable amount of research in selecting
the optimum performance cables and specifying the way in which they are used. It is strongly
recommended that the exact cables identified below (or a direct equivalent) should be used for the
installation.
Signal strength
• 24 AWG EcoMini 2 pair
cable
• Nominal diameter 4.22mm (0.166")
An example of this cable is 'Alpha Wire'- Mfr. Part No. 78172
This cables nominal diameter correctly fits the recommended Binder cable
back shell clamp (max allowed diameter 5mm)
Belden 8166
Six pair, 24 AWG low capacitance 'datalene' cable used for:
- Connections from HS20 to RCU10.
Note: Belden 8166 cannot be used to carry 24V DC power to an HS20 laser
head over distances greater than 10m (30ft) due to voltage drop. In this case
Belden 9874 may be used but does have inferior screening.
24 V power
4 core 18 AWG if used with voltage sense or 2 core 18 AWG if just required
cable for laser head grounding.
Maximum outer diameter: 7.3 mm
It is recommended that a screened cable is used
Figure 25 shows how the screen should be connected to the body of the 16 way connector to
ensure that these conditions are satisfied.
Figure 25 - Circular connector termination details
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