Servo power amplifier / E-STOP (25W D socket)
The connection on the UCC AI is a 25W D socket with the following connections:
External I/O +24 V
Axis 3 command -
/Contactor/ (active low)
Axis 3 command +
/Enable amps/ (active low)
Axis 0 command -
Axis 0 command +
Contactor feedback (active low)
Axis 1 command -
/Amps OK/ (active low)
Axis 1 command +
Axis 2 command -
Axis 2 command +
NOTE: The following servo power amplifier / E-STOP I/O pin structures can be referred to machine I/O diagrams and thresholds (see section 'Machine I/O (44W HDD socket)').
External I/O +24 V
+24 V dc supply provided for the use of contactors, relays and other motor control circuits. Current limit 1 A.
NOTE: Please be aware that the 1 A current is shared between the machine I/O and servo power amplifier connectors.
This command is issued by the UCC AI, to the amplifier, to engage the motor contactor. This output signal can drive the contactor directly providing its current consumption is within the output specification. This output signal is available in both an active low on pin 2 and an active high on pin 5.
This is a command from the UCC AI to the amplifier requesting it to enable its amplifiers. This output signal is provided as both an active low signal on pin 4 and as an active high signal on pin 21.
E-STOP A and E-STOP B
These are the connections from the amplifier E-STOP system to the MCU mounted emergency stop switch. E-STOP A is the high end and E-STOP B is the return.
CAUTION: If the UCC AI's MCU and RS232 devices are accidentally swapped, the RS232 CTS pin will be connected to the E-STOP B signal. The system installer must ensure that any power provided by a connected RS232 device's CTS signal will not allow the SPA E-STOP system to be enabled.
Axis command signals
These outputs (pins 8 to 15) are the velocity demand signals for each axis from the UCC AI to the servo power amplifiers. They vary over the range +10 V to –10 V.
An analogue zero reference is available, some third party units do require this reference. It is important that this is not used as a 0 V for digital signals because this will inject noise into the velocity demands. This pin (16) should be left open circuit if not required.
This is a confirmation signal (pin 22) from the motor contactor to the UCC AI that is has successfully operated and the motors are now engaged.
This is a confirmation signal (pin 23) from the servo amplifiers that they are on and ready. It is produced as a response to the 'enable amps' command.
This input (pin 24) is used to inform the UCC AI of the CMM ‘emergency stop' condition (E-STOP). If the input pin is pulled down to 0 V the UCC AI will assume that there is no emergency stop active and allow the servo motors to be energised.
If the input pin is open-circuit or above 4.2 V the UCC AI will assume that the emergency stop is active and will remove the motor demand signals, as well as the 'enable amps' and contactor commands.
NOTE: No motor can be enabled while this input is high or open-circuit.
This is the 0 V reference connection for all the digital and switching signals, unless otherwise stated the 0 V connections from all external devices should be connected to this line. This signal line is available on pin 25 on the SPA connector and pins 37 and 44 of the machine I/O connector. It is taken to a star point within the UCC AI controller where it is connected to protective ground, cable screens and all the internal supply 0 V lines. The star point must be the only point that these different 0 V and ground connections are made.
E-STOP electrical characteristics
- The UCC AI passes the E-STOP signal chain through the MCU E-STOP button and back to the attached amplifier
- Maximum current is 1 A (1000 mA)
- For details see the documentation for the MCU and amplifier used in the installation
Any emergency stop components fitted to this connector must have the following electrical characteristics:
|Emergency stop signal chain voltage||24 V|
|Emergency stop signal chain current||1 A maximum|
All connections to this connector should be fitted by a competent technician or engineer and all wires should be sleeved.
The machine manufacturer or product installer must perform a risk assessment to determine the requirements for emergency stopping and emergency switching off. The UCC AI emergency stop signal paths have been designed to be compatible with the category 2 architecture in standard ISO 13849-1:2015. The risk assessment should therefore have determined that a category 2 safety function is satisfactory.
CAUTION: It is strongly recommended that the CMM manufacturer or retrofitter includes a periodic test of the emergency stop and, if fitted, the associated reset switch in their maintenance instructions.
CAUTION: If an RS232 device is to be connected to UCC AI then the E-STOP risk assessment should specifically assess the consequences of accidentally connecting it to the MCU port.