Yamaha RCX-340 Safety Circuit

This is kind of a continuation of this thread.


Given this safety circuit diagram for the Yamaha RCX-340 Controller.



Would I be correct that in the second schematic any external safety trip/device is being completely bypassed?

*Bump*


Come on people. I want to know if I am just mis understanding this or not.

I would say no. In the first drawing, it looks like A4 is connected to A5, and B4 is connected to B5, through what I am going to guess is an opto isolator.

I think somebody already addressed the problem with the external 24v in a previous thread.

The other E-Stop connections are all connected wrong. Let's take A2 and A3 for an example. A2 is going to be the pulsed outgoing voltage to your safety device. When the device is closed, the pulsed voltage will go back in at A3. But it should be noted that this should be taken with a grain of salt because the real connections in this line are between T2 and IN4. IMO the best way to analyze this would be to trace all of the lines all of the way to their start and end points (ie. T2 - IN4)

I don't think anything is being bypassed here, but I do think that if this were energized it might let out some of that magic smoke. Hope this helps some.

The first diagram is just an example from the RCX-340 Instruction manual. In the second diagram test pulses are not being used on this device. OSSD1 and OSSD2 are just straight DC out from the safety controller.


The way I understand it A1 and B1 are V+ out which mean that OSSD1 and OSSD2 are doing nothering. A2 to A3 goes through and E-Stop contact on the pendant and back out so for B2 and B3. So the E-Stop pendant Has Just Main 24V+ control power going to. Then it goes back out to A4 and B4 which are the Actual Safety Inputs. Then A5 and and B5 got to A6 and B6 which are tied to 0V/Common internally.


Am I wrong?

I understand your point a little better now. In your drawing yes, 24 volts would go through A2 and B2, through the two e-stop contacts and go back into A3 and B3. That part sounds correct.

I think you might still be confused about A4 and B4. These are outputs from the safety controller that should only be energized when the e-stop is in a safe position. They control the optoisolators, but they also control two relays to energize the main power circuit. These branch up right after the names. So even if you did have the e-stops bypassed, your connections would not have driven the relays or optoisolators. Referencing the second drawing, A3 would not go to A4. They would both, theoretically, have 24V potential.

You are correct about A5, A6, B5, and B6 being tied together internally to the systems ground, so the jumpers on these terminals are a little redundant and made it kind of confusing to look at.

Sorry I have not been very clear. The second diagram is how my Senior Controls Engineer wired a previous machine. So since he is the senior guy and should know how to design this. I was wondering if I had somehow gone insane and didn't understand how the RCX-340 Controller works.



A2 to A3 is a dry in the Pendant E-Stop, so is b2 to B3. Technically A2 and B2 should have 24V+ on them and A3 and A4 should go back to inputs on the safety controller.



Doing it the way I said previously (A3 to A4 and B3 to B4) would mean the pendant E-Stop would kill the robot but not the rest of the safety circuit.