The external automatic operation mode of the KUKA robot allows its movement and operation to be controlled by external signals or commands. This mode is particularly suitable for application scenarios that require close integration with external devices (such as PLCs, sensors, etc.). The article “KUKA Robot Configuration External Automatic Operation & Super Useful Combination IO” has already involved some content. This article will give a detailed introduction to the relevant variables and processes. 1. Robot and PLC connection
The upper controller (for example, a PLC) can be used to control the robot process through the external automatic operation interface. The upper control system sends relevant signals of the robot process to the robot control system through the external automatic operation interface (such as operation permission, fault confirmation, program start, etc.).
The principle of KUKA robot’s external automatic operation mode is that the robot receives commands from an external controller or system. This enables coordinated operation with other equipment in a production line.
For configuration, it requires connecting to external control devices via communication interfaces like Ethernet. Then, parameters such as operation sequences and motion paths are set. Proper calibration is also crucial to ensure accurate movements.
The robot control system sends information about the operating status and fault status to the upper control system. In order to use the external automatic operation interface, the following configurations must be performed:
① Configure the CELL.SRC program.
② Configure the input/output end of the external automatic operation interface.
- Input end (from the perspective of the robot controller) variable description
1.PGNO_TYPE-Program number type This variable determines the format in which the program number transmitted by the upper control system is read. When the “N choose 1” transfer format is used, the values of PGNO_REQ, PGNO_PARITY and PGNO_VALID are not analyzed and therefore have no meaning.
2.PGNO_LENGTH-Program number length This variable determines the bit width of the program number transmitted by the superior control system. Value range: 1 … 16. If the value of PNGO_TYPE is 2, only bit widths of 4, 8, 12 and 16 are allowed.
3.PGNO_PARITY-Parity of program number The input terminal for the superior control system to transmit the parity bit. If the value of PNGO_TYPE is 3, PNGO_PARITY is not analyzed.
4.PNGO_VALID-Program number valid The input terminal for the superior control system to transmit the instruction to read the program number.
5.＄EXT_START-External start After setting this input terminal, a program (usually CELL.SRC) will be started or continued when the input/output interface is activated. Only the rising edge of the pulse of the signal is analyzed.
- $MOVE_ENABLE – Enable operation This input is used by the higher-level controller to check the robot drive. When the drive is stopped by the higher-level controller, the message “Start all operations” is displayed. The robot can only move again after this message is deleted and the external start signal is issued again. When starting operation, the variable $MOVE_ENABLE is often configured with the value $IN[1025]. If you forget to configure another input later, external start is not possible.
- $CONF_MESS – Confirm message By assigning a value to this input, the higher-level controller will acknowledge the fault message itself when the cause of the fault has been eliminated. Only the rising pulse edge of the message is evaluated.
- $DRIVES_ON – Drives on If a high pulse of at least 20 milliseconds is applied to this input, the higher-level control switches on the robot drives.
- $DRIVES_OFF – Drives off If a low pulse of at least 20 milliseconds is applied to this input, the higher-level control switches off the robot drives.
- Output (from the robot’s perspective)
Variable Description 1. ＄ALARM_STOP-Emergency Stop This output will reset when the following emergency stop situations occur:
①Press the emergency stop button on the KUKA control panel (KCP). (Internal emergency shutdown)
②External emergency stop When an emergency stop occurs, the status of the outputs ＄ALARM_STOP and int.NotAus can be used to determine which type of external emergency stop it is:
a. Both outputs are FALSE: The emergency stop button on the KUKA control panel (KCP) is triggered
b. ＄ALARM_STOP FALSE, int.NotAus TRUE: External emergency stop
- ＄USER_SAF-Operator protection/protective door This output is reset when the guardrail inquiry switch is opened (operating mode AUT) or the confirmation switch is released (operating mode T1 or T2).
- $PERI_RDY – Drive in standby state By setting this output, the robot control system informs the higher-level control system that the robot drive is switched on.
- $STOPMESS – Stop message This output is set by the robot control system to indicate to the higher-level control system that a message has appeared to stop the robot. (e.g. emergency stop button, operation start or operator protection device)
- $I_O_ACTCONF – External automatic operation activated The output is TRUE when the external automatic operation mode is selected and the input $I_O_ACT is TRUE (usually always set to $IN[1025]).
- $PRO_ACT – Program active/running This output is always assigned a value when a process is active on the robot level. The process is active when a program or interrupt is being processed. Program processing at the end of the program is only considered inactive after all pulse outputs and triggers have been processed.
*PGNO_REQ – Program number query When the signal at this output changes, the higher-level controller is requested to transmit a program number.
If the PGNO_TYPE value is 3, PGNO_REQ is not analyzed.
*APPL_RUN – Application is running
The robot control system informs the higher-level control system that the robot is processing the relevant program by setting this output.
*IN_HOME – The robot is at the home position (HOME).
This output informs the higher-level controller that the robot is at its home position (HOME). - Principle of external automatic operation communication
- Overview of the whole process
- Turn on the drive
Preconditions
＄USER_SAF-protective door is closed
＄ALARM_STOP-no emergency stop
＄I_O_ACTCONF-external automatic operation is activated
＄MOVE_ENABLE-allowed
＄DRIVER_OFF-unactivated drive device is turned off and the drive device is turned on
＄DRIVER_ON-turn on the drive device for at least 20ms. The drive device is in standby mode. ＄PERI_RDY-as soon as there is feedback from the drive device, the signal ＄DRIVER_ON is withdrawn
- Confirmation message prompt
Preconditions
＄STOPMESS-there is a stop message confirmation message prompt
＄CONF_MESS-confirmation message prompt The confirmable prompt message is deleted
$STOPMESS – no more stop message, $CONF_MESS can now be withdrawn
- Start program externally (CELL.SRC)
Preconditions
$PERI_RDY – drive is in standby state
$IN_HOME – robot is at home position (HOME)
No $STOPMESS – external start without stop message
$EXT_START – external start is switched on (pulse positive edge) CELL program is running
$PRO_ACT – report that CELL program is running
$ON_PATH – signal $EXT_START is withdrawn as soon as there is feedback that the robot is on the path
- Process program transfer and application
Preconditions
$PERI_RDY – drive is in standby state
$PRO_ACT – CELL program is running
$ON_PATH – robot is on the path
$IN_HOME – robot is at home position (HOME), no longer required for restart
PGNO_REQ – Program number query, program number transfer and confirmation (correct data type (PGNO_TYPE), program number length (PGNO_LENGTH) and first bit of program number (PGNO_FBIT) are set) application is running
APPL_RUN – Report that the robot leaves the home position (HOME) while the application is running, and the robot returns to the home position (HOME) after the application ends
- External automatic operation input configuration