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General wiring standards

To achieve reliable operation of the UCC2, UCC2-2 and the CMM's host computer, the following should be observed:

WARNING: It is essential that the UCC2 and UCC2-2 controller is connected to a mains supply earth. The recommended method of ensuring that the controller is earthed is to use the protective earth wiring in the AC supply cable and connector:

Earthing provisions for the complete machine are the responsibility of the manufacturer or installer.

Isolation: UCC2 and UCC2-2  is isolated by removing the mains connector. It is the responsibility of the installer or user to fit additional means of isolation if indicated by risk assessment.

Earth fault / residual current protection: It is the responsibility of the machine manufacturer or product installer to ensure an adequate level of protection for the complete machine installation. 

  • Scale readhead signals, reference marks and error signals should comply with EIA RS-422A. It is recommended that each readhead had its own screened cable and that these cables are kept well away from electrically noisy wiring such as motor supplies, etc.
  • All opto-isolated inputs and outputs should be separate from other connections to the UCC2 and UCC2-2 controller, so that the CMM's electrical system is kept isolated from the circuitry within the controller, with the exception of the 0 V reference and protective grounding.
  • The analogue ground ( if daughtercard fitted) for a 3rd party joystick compatibility should be dedicated only to that function.
  • The analogue ground for the analogue probe connections should be dedicated only to that function.
  • All signal cables MUST be screened and all cable screens should be connected electrically to the cable connector's metal shells. It is recommended that cable screens should only be connected to the protective earth (via the connector shell) at the UCC2, UCC2-2 ,SPA2-2 and SPA3 end, and not directly connected to the CMM's protective earth. This is to avoid earth loops. However, the protective grounding must be continuous between the controller and all other equipment in the installation.
  • All cable connectors should be secured to the UCC2 and UCC2-2 by the connector jack screws.
  • See also the installation instructions supplied with other Renishaw components in the system, i.e. probes or probe heads etc. Particular attention should be paid to the screening and earthing methods of the cables carrying low level signals from either analogue or touch-trigger probes.

NOTE: The UCC2 an UCC2-2 electronics 0 V rail is connected to the overall ground plane at a star point within the UCC2 and UCC2-2 and also to the protective ground of the ac supply. 


Before beginning the installation of the UCC2 and UCC2-2 ensure that:

  • All connecting cables, Ethernet link, daughtercards, test equipment and software are available
  • The CMM's measuring scales / readheads are correctly installed and are functioning
  • All the CMM status and limit switches etc. are correctly installed and have been function checked
  • All mains power has been removed from the CMM, CMM's host computer, CMM servo power amplifiers and CMM's axis drive motors etc.
  • The CMM and the UCC2 and UCC2-2 are in their final positions and that all connecting cables are of the required length