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.
KUKA robot’s external automatic operation mode allows the robot to work autonomously under external control. In this mode, it can receive commands from external devices such as a PLC. It’s designed to integrate with production lines smoothly. The robot precisely executes tasks like welding or palletizing as per the external signals, enhancing productivity and ensuring consistent quality in industrial settings.
- 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 (such as operation permission, fault confirmation, program startup, etc.) to the robot control system through the external automatic operation interface. 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. Important signals at the interface 2. Input terminal (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 superior control system is read, as shown in the following table. When the “N select 1” transmission format is used, the values of PGNO_REQ, PGNO_PARITY and PGNO_VALID are not analyzed and therefore meaningless. 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 bit 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, a program (usually CELL.SRC) will be started or continued when the input/output interface is activated. Only the rising edge of the signal pulse is analyzed.
- $MOVE_ENABLE – Enable operation
This input is used by the upper controller to check the robot drive. When the drive is stopped by the upper controller, the message prompt “Open all operations” is displayed. The robot can only move again after deleting this message prompt and re-issuing the external start signal.
When the variable $MOVE_ENABLE is put into operation, it is often configured with the value $IN[1025]. If you forget to configure another input terminal later, external start is not possible.
- $CONF_MESS – Confirm message prompt
By assigning a value to this input, the upper controller will confirm the fault message itself when the cause of the fault has been eliminated. Only the rising edge of the message pulse is analyzed.
- ＄DRIVES_ON – Drive device is turned on
If a high pulse lasting at least 20 milliseconds is applied to this input, the upper control system will turn on the robot drive device.
- ＄DRIVES_OFF – Drive device is turned off
If a low pulse lasting at least 20 milliseconds is applied to this input, the upper control system will turn off the robot drive device.
III. Output terminal (from the perspective of the robot) variable description
- ＄ALARM_STOP – Emergency stop
This output terminal will be reset in the following emergency stop situations:
① Press the emergency stop button on the KUKA control panel (KCP). (Internal emergency shutdown)
② External 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 query switch is opened (operating mode AUT) or the confirmation switch is released (operating mode T1 or T2).
- ＄PERI_RDY-drive is in standby state
By setting this output, the robot control system notifies the superior control system that the robot drive is turned on.
- ＄STOPMESS-stop message
This output is set by the robot control system to display to the superior controller a message prompting the robot to stop. (e.g. emergency stop button, operation start or operator protection)
- $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 on the robot level is active. The process is active when processing a program or interrupt. 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 transfer a program number.
If the value of PGNO_TYPE 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 upper controller that the robot is at its home position (HOME).
IV. External automatic operation communication principle
- Overview of the whole process
- Turn on the drive
Prerequisites
＄USER_SAF – the protective door is closed
＄ALARM_STOP – no emergency stop
＄I_O_ACTCONF – external automatic operation is activated
＄MOVE_ENABLE – enable
＄DRIVER_OFF – drive is not activated and turned off
Turn on the drive
＄DRIVER_ON – turn on the drive for at least 20ms
The drive is in standby state Status
＄PERI_RDY-As soon as there is feedback from the drive, the signal ＄DRIVER_ON is withdrawn
- Confirmation message prompt prerequisite
＄STOPMESS-There is a stop message
Confirmation message prompt
＄CONF_MESS-Confirmation message prompt
The confirmable prompt message is deleted
＄STOPMESS-There is no stop message, and now ＄CONF_MESS can be withdrawn
- Start the program from the outside (CELL.SRC)
Prerequisite
$PERI_RDY – Drive is in standby mode
$IN_HOME – Robot is at home position (HOME)
No $STOPMESS – No stop message
External start
$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
- Processing program transfer and application prerequisites
$PERI_RDY – Drive is in standby mode
$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 request is available
Program number transfer and confirmation
(correct data type (PGNO_TYPE), program number length (PGNO_LENGTH) and first bit of program number (PGNO_FBIT) Already set)
Application is running
APPL_RUN – Reports that the robot leaves the home position (HOME) while the application is running, and returns to the home position (HOME) after the application ends
- External automatic run input configuration