Device Monitor Guide

The Device Monitor is an important part of the alarming system on a Foxbro system. The Device Monitor keeps a list of statuses of workstation and printer destinations. This it passes on to CP stations so they don’t have to mess around with failed destinations when sending alarms and messages. The Device monitor software runs on each workstation on a Foxboro network. There are two modes of operation for the software, master or slave. Only one workstation should have the device monitor working in master mode. 

The master Device Monitor sends a mutlicast message to the slave Device Monitor alias (SLV_DEV_MON) every 90 seconds. All Device Monitors receive this message. If a slave Device Monitor does not receive three consecutive heartbeat messages the slave Device Monitor will attempt to become the master Device Monitor. If a master Device Monitor receives a heartbeat from another Device Monitor, the receiving Device Monitor relinquishes the mastership and operates as a slave Device Monitor. 

The master DEVICE MONITOR sends out the heart beat message every 90 seconds, if a master should receive a heartbeat he will give up being master, “mastership” become a slave and request Device monitor to perform a recon of the network. As part of this recon, the ‘current master’ will get current information about all of the printers on the network. As the master receives this printer info, it updates the heartbeat message with the current status.

The “dm_recon d” function can be issued at any processor, and sends a signal to the active DevMon station to report status. This is done by creating a text file on the active station and writing the status of alarm destinations for all stations on the network into it. The file it creates is /usr/fox/cs/cs_dm.current

dm_recon t 

directs the local station (where the command was run) to take over the active DevMon monitoring function. To find which station has the active DevMon functions running, there are two ways. One is to issue a

dm_recon d

wait a couple of minutes, then look around for which station has just created the text file. The second way is to use “glof” to find the ethernet address of the station containing the Device Monitor process, then use “fist” to find what station has that ethernet address.

/opt/fox/bin/tools/glof -p DEV_MONITOR 

find the MAC of a station

/opt/fox/bin/tools/fist LETTERBUG 


dm_recon d

Dumps the current status of device monitor on the master workstation in file /usr/fox/cs/cs_dm.current

dm_recon t

Directs this workstation to take over as device monitor master 

Version 8 
In the release notes for Version 8.2 V0700RN/B 
Section 3.4.7 
The device monitor operates across an ATS. The Device Monitor master will automatically run on a V8.x workstation and will automatically disable any potential Nodebus device monitor.

Location of files 
/usr/fox/cs/cs_devmon executable process 
/usr/fox/cs/cs_devmon.cfg configuration file 
/usr/fox/cs/dm_recon executable tool 

Startup Script 

More Help 
See helpful hints, 
HH843 HH832

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