General wiring standards for the installation of the SPA3

To achieve reliable operation of the SPA3 plus UCC, the following should be observed:

  • The PSU must be single fault tolerant, approved to EN60950-1 and must be connected to a supply incorporating a protective earth conductor (earthing provisions and residual fault protection for the complete machine are the responsibility of the OEM or installer)
  • The system must be PAT tested before the equipment is powered
  • 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 screens for motor cables should be connected to the shell on the SPA3 end and connected to the motor housing at the CMM end
  • Signal cables such as tacho and scale cables should be connected to the SPA3 and have a cable shield that runs to the machine but is left unconnected at the machine end
  • Please refer to appropriate product installation guides when installing other Renishaw components
  • Supply and motor cables that are used to connect the SPA3 to the CMM (that are not data cables) must have a minimum cross section of 0.3 mm(as specified in EN  60204-1 para.12.6.)
  • SPA3 has a maximum voltage of 80 Vdc and peak current is 10 A (the actual peak current will be dependent on the size of the motor fitted and how hard it needs to be driven, so cable sizes need to be calculated by the system installer)
  • All cable connectors should be secured to the SPA3 by the connector jack screws.


The power input to the SPA3 is via a 3W3 connector; refer to the Connector and signals section for more information.

SPA3 power requirements

The SPA3 amplifier requires 30 W of power to operate. This must be factored into the power supply used.