I/O signals, also known as input/output signals, are electrical signals used by robots to communicate with peripheral devices such as end effectors and external devices. Fanuc robot I/O signals can be divided into general I/O signals and special I/O signals. General I/O signals refer to signals that can be freely defined by users, while special I/O signals refer to IO signals with a certain purpose that cannot be freely defined by users.
Fanuc robots have various I/O types. They include digital I/O for simple on/off signals, analog I/O for continuous value signals, and group I/O for handling multiple signals as a group. Configuration is done through the robot’s programming interface. You can define the function and address of each I/O point to match the specific needs of the application, enabling seamless interaction with other devices and systems.
- Classification of IO signals
1.1 General IO signals General IO signals are divided into the following three categories:
(1) Digital IO signals
They are general digital signals that are processed from peripheral devices and divided into digital input DI[i] and digital output DO[i]. The values of digital signals are ON and OFF.
(2) Group IO signal
Group IO signal is a general digital signal that aggregates multiple signal lines and exchanges data. It is expressed as GI[i] / GO[i]. The value of the group signal is expressed as a numerical value (decimal/hexadecimal number). After conversion or inversion into a binary number, the data is exchanged through the signal line.
(3) Analog IO signal
Analog IO signals are divided into analog input AI[i] and analog output AO[i]. When reading and writing, the analog input/output voltage value is converted into a digital value. Note: The [i] of these IOs represents the logical number of the signal number and the group number.
1.2 Dedicated IO signal
Dedicated IO signals are divided into the following three categories:
(1) Peripheral device (UOP) IO signal
Peripheral device (UOP) IO signals are divided into peripheral device input signals UI[i] and peripheral device output signals UO[i].
(2) Operation panel (SOP) IO signal
The operation panel (SOP) IO signal is a digital dedicated signal used to exchange status data between buttons and LEDs on the operation panel and operation box. It is divided into input signal SI[i] and output signal SO[i].
(3) Robot IO signal
The robot IO signal is a robot digital signal used as the end effector I/O via the robot. It is divided into robot input signal RI[i] and robot output signal RO[i].
Note: The [i] in these IOs represents the logical number of the signal number and group number. - IO allocation
2.1 Basic description
When performing I/O allocation, it is necessary to set the rack number, slot, and start point.
(1) Rack number
The rack refers to the type of IO module. The figure below shows the rack number of FANUC robots. For example, if the rack number is 89, it means that EthernetIP communication is used.
(2) Slot
The slot refers to the number of the I/O module that constitutes the rack.
When using the processing I/O printed circuit board and I/O connection device connection unit, the order of connection is slot 1, 2, etc. When using I/O Unit-MODEL A, the I/O module is installed. When using I/O Unit-MODEL B, the unit number set by the DIP switch of the basic unit is the slot value of the basic unit. In the I/O connection device slave interface and the main board (CRMA15, CRMA16) of the R-30iB Mate, this value is always 1. When using flags and identifiers, the flag is always set to 1 and the identifier is always set to 2. It is always 1 in the always-ON state. (3) Start point The start point allocates physical numbers to logical numbers for signal line mapping. (4) Status There are 4 states after IO allocation: PEND, ACTIV, INVAL, and UNASG. PEND: The allocation is valid and needs to be restarted to take effect. After restart, it will change to ACTIV; ACTIV: The allocation is valid and is in use; INVAL: Invalid allocation, the IO in this range is ineffective. UNASG: Unallocated.
2.2 Digital signal allocation
(1) Press the [MENU] button, select “5 I/O”, and select “3 Digital” on the type interface.
(2) Press F2 [Assign] to enter the digital output allocation interface, fill in the DO range, fill in the rack number as 89 (using EthernetIP communication), set the slot to 1, and set the start point to 1. This means that DO[1]-DO[20], these 20 points of signal are at the first 20 points on the IO module.
(3) After the allocation is completed, restart the control cabinet. After the restart, the IO status changes from PEND to ACTIV.
(4) When F3 [IN/OUT] is pressed, you can switch between digital input/digital output. The allocation of digital input is the same as the allocation of digital output.
2.3 Group signal allocation
(1) Press the [MENU] button, select “5 I/O”, and select “5 Groups” on the type interface.
(2) Press F2 [Assign] to enter the group output GO allocation interface.
(3) The following items need to be filled in:
A. Rack: the type of I/O communication device;
B. Slot: the number of I/O modules;
C. Start point: the starting point signal position corresponding to the IO number;
D. Points: refers to the number of signals allocated to a group
Note: The number of signals allocated to a group can be 2 to 16.
(4) Set to allocate 4 digital output DO (DO21~DO24) as a group.
2.4 Peripheral device IO signal allocation
Peripheral device IO (UI/UO) is a dedicated signal with a determined purpose in the system. There are the following types of automatic allocation of UOP:
There are two types of allocation of peripheral device I/O (UOP): full allocation and simplified allocation.
Full allocation allows all peripheral I/Os to be used, and 18 input points and 20 output points of physical signals are allocated to peripheral I/Os;
Simplified allocation allows peripheral I/Os with fewer signal points to be used, and 8 input points and 4 output points of physical signals are allocated to peripheral I/Os.
In simplified allocation, the number of peripheral I/O points is reduced, so the number of signal points that can be used for general digital I/O increases, and the functions of peripheral I/O are limited.
A.CSTOPI is assigned to the same signal as RESET, so if “Forced program termination with CSTOPI signal” is set to valid, the program can be forced to exit by RESET input.
B.PNSTROBE is assigned to the same signal as START, so the program is selected at the rising edge (OFF→ON) of the START signal, and the program is started at the falling edge (ON→OFF) of the START signal.
C.In case of simplified allocation (START has been assigned to the same signal as PNSTROBE), program selection methods other than PNS cannot be used. If “Program selection mode” is set to other than PNS on the program selection screen, it will automatically change to PNS when the power is turned on.
D. It will be assigned to the internal I/O (rack 35, slot 1) that is always ON.
E. PROD_START will not be assigned in the simplified assignment, so when the “Restart dedicated signal (external START)” on the system setting screen is set to valid, the program will no longer be able to start from the peripheral device I/O. In the case of simplified assignment, please set “Restart dedicated signal (external START)” to invalid.
The steps for peripheral device IO signal assignment are the same as those for digital signal assignment. The rack number, slot and start point are set in the same way. After correct assignment, restart the device.