Introduction

This document will review the definitions for Emergency Stop categories and explain when and how they are used in Yaskawa Motoman robots.

Definitions: Stop Categories (0, 1, 2)

Type	Immediate Action	Secondary Action
Stop Category 0	The immediate insulation of the motor power source to servo motor causes the stop.	After the motor power is insulated, the manipulator and the external axis decelerate by the brake and stop. The manipulator and the external axis may run off the operation path.
Stop Category 1	The manipulator and the external axis are controlled on the operation path, decelerate and then stop.	After the stop, the manipulator and the external axis are locked by the brake and the motor power is insulated.
Stop Category 2	The manipulator and the external axis are controlled on the operation path, decelerate and then stop.	After the stop, the stop position is retained in a state where the motor power is being supplied.

As you can see, a “CAT 0” stop is the most aggressive – power is dropped and the brakes are applied immediately. If this were a car, it would be like turning off the engine and slamming on the brakes. The robot is built to handle this, but regular use would cause excessive wear. Robot Programmers and Operators should not be in the habit of using the Programming Pendant E-Stop to pause a job during testing or operations. Instead, the Hold button should be used. Other instances where a Cat 0 stop is used are shown in the table below.

When are these stop categories used?

The table below is from section 5.3.3 of the YRC1000 Instructions Manual. So, for example, when you are in TEACH mode and press the E-Stop button on the Programming Pendant (PPESP) a Cat 0 Stop is issued. If in PLAY mode, that would be a CAT 1 stop.

Using an E-Stop Signal as an INPUT

The existence of an E-Stop condition can be detected in the Safety Logic Circuit, and additional logic can be added after the “secondary actions” defined above. The following E-Stop signals can be used as inputs in the Safety Logic Circuit. An example of when you might use these would be if an alarm needs to be sounded when an employee presses an Emergency Stop connected to the cell (EXESP.)

Signal	Description
EXESP	External emergency stop input signal
PBESP	Controller emergency stop signal
PPESP	Programing Pendant emergency stop signal
S-EXESP	External emergency stop signal in the safety logic circuit

Issuing an E-Stop Signal

The following stop signals can be used as outputs in the Safety Logic Circuit. An example of when you might use these would be if an area scanner that has detected personnel approaching an operating robot and you want to issue a Category 1 stop (SVOFF CAT1).

Signal	Description
S-EXESP	External emergency stop signal in the safety logic circuit
SVOFF CAT0	Turns OFF the servo power supply to the robot. (Category0 stopped)
SVOFF CAT1	Turns OFF the servo power supply to the robot. (Category1 stopped)

Examples

In the image below, a Safety Logic Circuit is shown. The line highlighted in blue shows when the Programming Pendant E-Stop (PPESP) is pressed, Safety Fieldbus Output Signal 01 (SFBOUT01) is triggered. In yellow, it shows when Safety Fieldbus Input Signal 01 (SFBIN01) is received a CAT 0 E-Stop (SVOFF CAT0) is issued.

More information on the Safety Logic Circuit and signals available to use are in section 8.26 of the YRC1000 Instructions Manual.

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E-Stop Categories and Use