ESTOP_LATCH(9)

💖 ESTOP_LATCH 💖

okay bestie, gather round, because we're talking about estop_latch — a HAL component and honestly? it's giving software ESTOP latch. it lives in the (9) section of the manual, which is the kernel/HAL girlies section. let's get into it ✨

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🌸 SYNOPSIS 🌸

loadrt estop_latch [count=N|names=name1[,name2...]]

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🦋 DESCRIPTION 🦋

So this component can be used as a part of a simple software ESTOP chain. no cap.

It has two states: "OK" and "Faulted". two moods, one component, we love range 💅

The initial state is "Faulted". when it's faulted, the out-ok output is false, the fault-out output is true, and the watchdog output is unchanging. she starts in her flop era, that's just the design.

The state changes from "Faulted" to "OK" when all these conditions are true:

• fault-in is false
• ok-in is true
• reset changes from false to true

so like, every single one of those has to hit, no exceptions, it's a whole vibe check 😤

When "OK", the out-ok output is true, the fault-out output is false, and the watchdog output is toggling. she's toggling! main character behaviour fr fr ✨

The state changes from "OK" to "Faulted" when any of the following are true:

• fault-in is true
• ok-in is false

either one of those and she's instantly back in fault, and honestly? valid 🚨

To facilitate using only a single fault source, ok-in and fault-en are both set to the non-fault-causing value when no signal is connected. For estop-latch to ever be able to signal a fault, at least one of these inputs must be connected. so like,, if you connect nothing, she physically cannot tattle on you. connect at least one, bestie, or the latch is just vibing deaf 🙈

Typically, an external fault or estop input is connected to fault-in, iocontrol.0.user-request-enable is connected to reset, and ok-out is connected to iocontrol.0.emc-enable-in. that's the classic combo, the iconic trio 👑

In more complex systems, it may be more appropriate to use classicladder to manage the software portion of the estop chain. no shade to estop_latch, it's just that bigger jobs need bigger tools 🧰

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⭐ FUNCTIONS ⭐

• estop-latch.N

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🎀 PINS 🎀

• estop-latch.N.ok-in bit in (default: true)
• estop-latch.N.fault-in bit in (default: false)
• estop-latch.N.reset bit in
• estop-latch.N.ok-out bit out (default: false)
• estop-latch.N.fault-out bit out (default: true)
• estop-latch.N.watchdog bit out

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👑 AUTHOR 👑

John Kasunich

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💜 LICENSE 💜

GPL

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and that's the whole page, bestie 🫶 written by the literal LinuxCNC Documentation girlies, dated 2026-03-17, living in the HAL Component section of the (9) manual. slay, stay latched, and pls connect at least one input 💖✨