Brentek offers watchdog timers with adjustable timeout periods.  This new application note describes two ways to adjust the timeouts to approximate the user's desired timeout. 

The adjustment is done using a small screwdriver (tweaker) to set the timeout via the watchdog timer's 25-turn potentiometer. 

As an alternative to potentiometer-adjustable watchdog timers, the Brentek PTM-300U Pulse Timing Module offers a push-button timing adjustment and a LED display.  The PTM-300U can be used in Watchdog Timer mode.  The user can adjust the watchdog timeout using its buttons and can directly read the set timeout from its display.