NAME

       watchdog - monitor multiple inputs for a "heartbeat"

SYNOPSIS

       loadrt watchdog num_inputs=N

       You must specify the number of inputs, from 1 to 32.  Each input has a separate timeout value.

FUNCTIONS

       process
              Check  all  input pins for transitions, clear the ok-out pin if any input has no transition within
              its timeout period.  This function does not use floating point, and should  be  added  to  a  fast
              thread.

       set-timeouts
              Check  for timeout changes, and convert the float timeout inputs to int values that can be used in
              process.  This function also monitors enable-in for false  to  true  transitions,  and  re-enables
              monitoring  when  such a transition is detected.  This function does use floating point, and it is
              appropriate to add it to the servo thread.

PINS

       watchdog.input-n bit in
              Input number n.  The inputs are numbered from 0 to num_inputs-1.

       watchdog.enable-in bit in (default: FALSE)
              If TRUE, forces out-ok to be false.  Additionally, if a timeout occurs on any input, this pin must
              be set FALSE and TRUE again to re-start the monitoring of input pins.

       watchdog.ok-out bit out (default: FALSE)
              OK output.  This pin is true only if enable-in is TRUE and no timeout  has  been  detected.   This
              output  can be connected to the enable input of a charge_pump or stepgen (in v mode), to provide a
              heartbeat signal to external monitoring hardware.

PARAMETERS

       watchdog.timeout-n float in
              Timeout value for input number n.  The inputs are numbered from 0 to num_inputs-1.  The timeout is
              in seconds, and may not be below zero.  Note that a timeout of 0.0 will likely prevent ok-out from
              ever becoming true.   Also  note  that  excessively  long  timeouts  are  relatively  useless  for
              monitoring purposes.

LICENSE

       GPL

LinuxCNC Documentation                             2010-06-22                                        WATCHDOG(9)