B&B Electronics I-7060 - Quick Start Guide - Manual (Page 38)

Getting Started for I-7000 Series Modules
Date: Jan-08, 2002 Version 1.02 page: 38
5.2 Host Watchdog
The host may be down for the following reasons:
1. excessive noise
! host hardware goes into error
2. software problem
! host changes to dead lock mode
3. hardware problem
! host hardware is damaged
4. the RS485 network is open
! cannot send out commands to modules
The host-watchdog (software) is designed to monitor the host computer.
If the host computer is down, the output of the I-7000 modules will
automatically go into their safe states to avoid unpredictable damage.
Figure 5-2-1. Host PC sends the “ ~** ” command to every module.
The Host PC is OK.
Figure 5-2-2. Host PC cannot send command to any module.
Every Host-Watchdog sets its module to go into safe state.