ESTOP_LATCH(9)

NAME
estop_latch - Software ESTOP latch

SYNOPSIS

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

DESCRIPTION

This component can be used as a part of a simple software ESTOP chain.

It has two states: "OK" and "Faulted".

The initial state is "Faulted". When faulted, the out-ok output is false, the fault-out output is true, and the watchdog output is unchanging.

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

When "OK", the out-ok output is true, the fault-out output is false, and the watchdog output is toggling.

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

    • fault-in is true

    • ok-in is false

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.

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.

In more complex systems, it may be more appropriate to use classicladder to manage the software portion of the estop chain.

FUNCTIONS

estop-latch.N (requires a floating-point thread)

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

AUTHOR

John Kasunich

LICENSE

GPL