Any piece of machinery with moving parts that can potentially hit or even injure somebody
must have a way of turning them off in case of an unexpected situation.
The DOFReality platforms have an (optional) "EMERGENCY STOP" button for this.
It is plugged into the control boxes and, when pressed, closes a circuit that powers
a relay, which in turn cuts power to the motors. And here is where the problem lies: because
this button is optional and therefore the control boxes also need to work without it, it can
only "close" a circuit to tell the boxes to cut power. In order to function as a real
safety feature, however, such a button must itself open a connection when pressed.
There are several reasons for this:
- The cable that goes from the button to the control box might get broken.
- The plug might be pulled out of the box.
- The button might be damaged and won't close the connection.
- The relay might be broken and won't engage when powered.
Fortunately, there is an easy way to convert this into a real safety feature. All it takes
is to swap some wires, as shown in the images below.
CAUTION: Make sure the control boxes are disconnected from main power before opening them!
That's it! Now your platform will only move if all safety features are working.
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