Limit switches
Sixteen inputs are allocated to limit switch signals, 8 inner and 8 outer. When a limit switch is not activated (i.e. the machine is within its
working range) these inputs should be connected to the 24 V return line by the limit switch contacts. If the machine installation does not
require the connection of the limit switches the signals must be connected to the 24 V return line.
NOTE:
Limit switches should be installed such that they will not be damaged in the event of overtravel. Where necessary for safety
related functions, they should be of the direct (or positive) operating type to IEC 60947-5-1).
Amplifier OK and contactor feedback
The ‘amplifier OK' and the ‘contactor feedback' inputs have been discussed in
"Motor engagement via SPA connector"
Fatal fault
Three ‘Fatal Fault' inputs are provided: emergency stop, machine air pressure low and a ‘Crash Switch' input. This last is intended for use with
a sensing mechanism which detects an unintended contact between the machine's moving and fixed components. The controller monitors
these inputs and will stop the motors if one or more input goes open circuit or high. If not required these inputs should be connected to the
24 V return line.
NOTE:
The ‘emergency stop' input is not a primary safety device, although the controller will stop the motors as far as it can. Its
main use is to allow the controller to inform the main computer, and hence the operator, of the ‘emergency stop' switch actuation.
In addition it will prevent motor re‐engagement if the ‘emergency stop' switch is still activated. Where an electromechanical
controlled emergency stop is required, to IEC/ EN60204-1 category 0, it must be separately provided and external to the UCC2.
Declutched mode
The ‘CMM in declutched mode' input is intended to tell the controller that the driving motors are mechanically disconnected from the
machine, and that the machine may be moved by some other means, e.g. by hand. In this state, the motor commands will be kept at zero
velocity until the machine clutches are re-engaged, at which time the controller will resume servo control at the new machine position. For
normal servo operation, this input should be pulled down to the 24 V return line. If this function is not required, the input should be connected
to the 24 V return line.
Uncommitted inputs
The remaining six inputs are uncommitted and may be used as required. These signals are not used by the controller and are simply passed to
the main computer, on request. If not required these inputs should be connected to the 24 V return line.
UCC2 and UCC2-2 installation guide
www.renishaw.com
Issued 07 2021
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