DENSO robots basic Safety Circuits

Modified on Mon, 06 Mar 2023 at 04:16 PM

Each DENSO robot must have its three primary safety circuits wired in for full Automatic operation.  These include the Emergency Stop Circuit, Protective Stop Circuit, and Auto Enable Circuit.

For jogging/movement of the robot arm in manual mode, only the emergency stops must be wired in.  For any movement of the arm in Teach Check or Auto modes, all three circuits must be wired in and completed.


When an E-stop is pressed, the robot will execute an active stop which causes the robot to stop as quickly as possible and kill motor power. In addition, by default, the programs that were running will be stopped and reset. Hence, you cannot resume the program from when the e-stop was executed. This setting can be changed on the controller (See Continue Function)

The Protective stops and Enable Auto serve similar functions. When opened up, the robot stops similarly to an e-stop in that the robot will stop and motor power will turn off. The main difference is the program will stop but all programs will be put into a suspended state meaning they will stay on the line where the protective or enable auto signal was dropped. This allows the programs to be resumed once all stop conditions are cleared. Note, if you try to resume before clearing all stop conditions, the robot will not allow you to resume and the programs will be reset. Also, when either the protective stop or enable auto are opened up, the robot controller is placed back into manual mode. You will likely notice multiple enable auto-off errors when this occurs. 


The difference between the protective stop and enable auto is based on how you integrate them into the system. Protective stops are normally reserved for safety devices such as door interlocks, light curtains, safety mats, etc. The enable auto is normally wired to a simple toggle switch and is used to manually switch between auto and manual modes.


The safety signals for the DENSO robot, for the RC8, RC8A, and RC8A Safety Motion controllers will always come through the Mini I/O cable.  This will be the case regardless of whether or not you're using the Mini I/O for systems I/O, User I/O, etc.  The safety signals mentioned above will still need to be wired in via the Mini I/O cable.  Safety motion is its own thing and is entirely separate from what is discussed in this article.

[PNP Type] Safety Circuit for RC8A

[NPN Type] Safety Circuit for RC8A

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