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PowerBrick STO


AnthonyLH
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Dear all,

I have some difficulties understanding exaclty what are the differences between "BrickAC.STO0" and the "BrickAC.STO1".

 

I have only 1 wire connected to the STO connector. It goes to the pin3 "STO IN". The wire supplies 24v when the Emergency Stop is not pressed.

 

From what i observe:

BrickAC.STO0 is always at 0.

BrickAC.STO1 is at 0 when 24v is supplied, at 1 when emergency stop is pressed.

 

The documentation talks about:

STO0 : “Safe torque off” STO0 input state

STO1 : STO1 disable condition control input state

 

It seems like there is a link with the DYN Brake input.

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Dear all,

I have some difficulties understanding exaclty what are the differences between "BrickAC.STO0" and the "BrickAC.STO1".

 

I have only 1 wire connected to the STO connector. It goes to the pin3 "STO IN". The wire supplies 24v when the Emergency Stop is not pressed.

 

From what i observe:

BrickAC.STO0 is always at 0.

BrickAC.STO1 is at 0 when 24v is supplied, at 1 when emergency stop is pressed.

 

The documentation talks about:

STO0 : “Safe torque off” STO0 input state

STO1 : STO1 disable condition control input state

 

It seems like there is a link with the DYN Brake input.

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A few issues here:

 

The two inputs are two "hardware-only" methods of bringing the motor to a stop by not permitting external torque commands to be applied to the motor.

 

One input removes the power from the gate drivers of all 6 transistors, turning them all off. When power is removed from this input, the motor will coast to a stop.

 

The other input removes the power from the gate drivers of the 3 top transistors, turning them off, but keeps the bottom transistors enabled. When power is removed from this input, the motor will dynamically brake to a stop by the resistance in the windings that are effectively shorted together. This will be a quicker stop than coasting.

 

Both of these were intended to be "safe torque off" controls, and the programmers labeled the status bits this way. But it turns out that in some regulatory environments, you cannot call the second case (dynamic braking) a "safe torque off". (And our original concept that the second input would control the mode of stopping, which got documented first, also did not pass regulatory muster.)

 

So we modified the external description of the second input to "Dyn Brake". However, in doing so, we got the two inputs mixed up.

 

Our apologies for the confusion.

 

Pin 2 of the STO (A11) connector on Power Brick AC is the "STO" input. This state of this input can be monitored from PMAC using BrickAC.STO0 status register. If the input is connected to 24VDC, BrickAC.STO0 reports a 0. If 24VDC is removed from this pin, BrickAC.STO0 reports a 1.

 

Pin 3 of the STO (A11) connector on Power Brick AC is the "Dyn Brake" input.This state of this input can be monitored from PMAC using BrickAC.STO1 status register. If the input is connected to 24VDC, BrickAC.STO1 reports a 0. If 24VDC is removed from this pin, BrickAC.STO0 reports a 1.

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A few issues here:

 

The two inputs are two "hardware-only" methods of bringing the motor to a stop by not permitting external torque commands to be applied to the motor.

 

One input removes the power from the gate drivers of all 6 transistors, turning them all off. When power is removed from this input, the motor will coast to a stop.

 

The other input removes the power from the gate drivers of the 3 top transistors, turning them off, but keeps the bottom transistors enabled. When power is removed from this input, the motor will dynamically brake to a stop by the resistance in the windings that are effectively shorted together. This will be a quicker stop than coasting.

 

Both of these were intended to be "safe torque off" controls, and the programmers labeled the status bits this way. But it turns out that in some regulatory environments, you cannot call the second case (dynamic braking) a "safe torque off". (And our original concept that the second input would control the mode of stopping, which got documented first, also did not pass regulatory muster.)

 

So we modified the external description of the second input to "Dyn Brake". However, in doing so, we got the two inputs mixed up.

 

Our apologies for the confusion.

 

Pin 2 of the STO (A11) connector on Power Brick AC is the "STO" input. This state of this input can be monitored from PMAC using BrickAC.STO0 status register. If the input is connected to 24VDC, BrickAC.STO0 reports a 0. If 24VDC is removed from this pin, BrickAC.STO0 reports a 1.

 

Pin 3 of the STO (A11) connector on Power Brick AC is the "Dyn Brake" input.This state of this input can be monitored from PMAC using BrickAC.STO1 status register. If the input is connected to 24VDC, BrickAC.STO1 reports a 0. If 24VDC is removed from this pin, BrickAC.STO0 reports a 1.

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