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matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 11094

Posted: 03:26pm 19 Mar 2026

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Probably no correct answer but...

If I get an estop condition should I remove the enable on the motion drivers?

For: guarantees power is removed
Against: axis momentum could cause more issues

PhenixRising
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Joined: 07/11/2023
Location: United Kingdom
Posts: 1791

Posted: 04:10pm 19 Mar 2026

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In the context of closed loop servo motors:

A regular e-stop, I change the current decel ramp to as fast as is reasonable. Use the motor power to bring the motor to a controlled stop and then disable. Coasting can be catastrophic.

If the e-stop is caused by a servo loop going awry (servo-amp, feedback, etc.) then disable immediately.

In some applications, my motors feature an integral brake (fail-to-safe).

Don't know about open loop steppers, though.

Mixtel90

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Joined: 05/10/2019
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Posted: 04:23pm 19 Mar 2026

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It's a case of which is the lesser of two evils - let the thing come to a natural stop or use some sort of braking to prevent damage from inertia. Industrial approaches often use the latter, with mechanical brakes held off by a control supply. If that supply fails the brakes come on. If the device is still being powered then it will probably trip it's overcurrent protection. Pumps and medium size fans are usually just left to freewheel to a stop.

A motion drive module may be configurable to use electrical braking if disabled (e.g. both top or bottom devices in a H bridge turned on to short circuit the motor).

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

PhenixRising
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Posted: 04:33pm 19 Mar 2026

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Quote Dynamic Braking in Stepper Motors
Dynamic braking is possible with stepper motors, but it's implemented differently than in traditional DC or AC motors.

Understanding Dynamic Braking
Dynamic braking involves using the motor's own energy to slow it down quickly. When a stepper motor is decelerating, the energy generated during this process can be reused or dissipated through various methods:

Regenerative Braking: This method recovers energy by feeding it back into the power supply or storage elements (like capacitors). However, this is less common in standard stepper motors.
Resistive Braking: In this approach, the motor's windings are short-circuited, converting kinetic energy into heat. This method is typically straightforward and effective for rapid deceleration.
Motor Feedback and Control Systems: Using a closed-loop system, you can dynamically manage the braking process. Sensors can detect the motor's position and speed, allowing for more precise control over the dynamic braking method.

Mick, yeah I had to ask ChatGPT it dynamic braking worked for steppers

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