Periodical audits of networked resources within manufacturing systems.
Key words: Manufacturing systems, production systems, machine tools monitoring, data acquisition
The basic questions for monitoring of resources located in networked manufacturing systems are:
* which parameter or event to monitor
* how to acquire the data presenting selected parameter or event
* how to log and transform acquired data for later graphical display in the proper format for front-end software
There is much valuable information located in the local manufacturing system, important for monitoring, management and supervising of manufacturing systems, for example:
* runtime/ uptime status of each resource
* number of resources (machines, robots, assembly devices, workstations, etc.) logged into the local manufacturing network
* how continous is the connection between selected resources
* how continous is the connection from/to the Internet provider
* traffic load on selected check-points
* any other variables, which can be acquired from the network every defined time period and then represented as a numeric variable.
The problem of the data acquisition can be solved in a different way, depending on individual features of the system modules, like: type of hardware and software modules installed in manufacturing system.
The presented method uses the following software tools for the monitoring of manufacturing resources:
* the Stealth Port Scanner for Network Exploration and Security Audits (map), which is part of UNIX operating systems (or can be downloaded via the Internet from the author's web page)
* regular commands available in UNIX operating systems--like ping, traceroute, netstat, cron, grep and other commands
* Multi Route Traffic Grapher (MRTG), which can be used:
* to log the data obtained from selected resources within networked manufacturing systems and
* for the graphic presentation of results: using MRTG it is possible to monitor any variable which can be described by an integer value
2. AUDIT OF MANUFACTURING RESOURCES
An audit of all manufacturing resources connected to the local manufacturing network can be done using the Stealth Port Scanner for Network Exploration and Security Audits Tool--nmap. The aim of such an audit is to obtain information about the actual status of networked manufacturing resources like ethernet enabled machines, machine tools, robots, work cell computers as well as Computer Aided Design (CAD), Computer Aided Manufacturing (CAM), Computer Aided Production Planning (CAPP) and Manufacturing Resource Planning (MRTII)/ Enterprise Resource Planning (ERP) work stations and servers. The command for such an audit, using namp "ping scan"--one of the functions available in the Stealth Port Scanner for Network Exploration and Security Audits is:
/usr/bin/nmap -sP (IP address range)
Sample nmap "ping scan" command for single IP address:
/usr/bin/nmap -sP 192.168.1.1
This command runs an audit for one selected manufacturing resource placed under the indicated IP address and gives--as audit result--the text output (sample: see Fig. 1):
Sample nmap "ping scan" command for entire manufacturing local network (C-class, 255 IPs):
/usr/bin/nmap -sP 192.168.1.1-255
This command runs an audit for the IP range 1-255 and gives--as result--text output (sample: see Fig. 2):
3. PERIODICAL AUDITS
Such an audit can be repeated for every defined time period using "cron" deamon, presented in each UNIX based system. Using crontrab it is possible to run an audit every 5 minutes and write results to a file (see: Fig. 3)
After we have saved results of an audit in a file, we can analyze this file and forward the results to a front-end software module. Using other UNIX commands (cat + grep + wc), we can read results, then grep and count selected lines (see Fig. 4).
After completing those operations, our system will have a final result--the total number of active resources which are online (in the case presented result is: 12).
This result is ready to be accepted by the front-end software, however it must be converted (using a simple software script) to the format readable by MRTG.
After this operation MRTG can read it, save it--and, when requested: display the results as web pages.
4. SAMPLE MONITORING RESULTS
Sample results of monitoring show graphs generated by MRTG (see Fig. 5, 6, 8, 9).
[FIGURE 5 OMITTED]
[FIGURE 6 OMITTED]
The information about selected resources can be also acquired by grep in the main audit file (see: Fig. 3)
This allows us to make just one general audit for all resources connected to a local network. Based on an audit results saved in one file, it is possible to grep the status of each networked manufacturing resource (see Fig. 5).
Other information manufacturing network, such as latency time (see: Fig. 8) or extablished tcp connections (see: Fig. 9) can be obtained using UNIX commands, and--after conversion to the proper format--can be also presented using MRTG.
[FIGURE 8 OMITTED]
[FIGURE 9 OMITTED]
The presented method for periodical audits of manufcturing resources uses a set of software modules and tools available in UNIX systems on GNU license, making both a useful flexible monitoring system, capable of being utilized in any size of networked manufacturing systems.
The Free Stealth Port Scanner for Network Exploration and Security Audits, 2005, www.insecure.org/nmap
The GNU: General Public License: http://www.gnu.org and the GNU Polish translation: Powszechna Licencja Publiczna, http://gnu.org.pl/text/licencja-gnu.html
Tobias Oetiker, Dave Rand: The Multi Router Traffic Grapher, 2005, www.mrtg.org
Tobias Oetiker: RRDtool 1.2, 2005 http://rrdtool.eu.org
Fig. 1 Sample audit of a single manufacturing resource using using nmap "ping scan" command: Starting nmap 3.50 at 2005-07-06 13:25 CEST Host cad202.inpoland.pl (192.168.1.202) appears to be up. map run completed--1 IP address (1 host up) scanned in 0.310 seconds Fig. 2 Sample audit of manufacturing network using using nmap "ping scan" command: Starting nmap 3.50 at 2005-07-06 13:25 CEST Host machine2.inpoland.pl (192.168.1.2) appears to be up. Host machine3.inpoland.pl (192.168.1.3) appears to be up. Host machine7.inpoland.pl (192.168.1.7) appears to be up. Host machine10.inpoland.pl (192.168.1.10) appears to be up. Host machine14.inpoland.pl (192.168.1.14) appears to be up. (...) Host robot112.inpoland.pl (192.168.1.112) appears to be up. Host robot121.inpoland.pl (192.168.1.121) appears to be up. Host robot122.inpoland.pl (192.168.1.122) appears to be up. (...) Host cad201.inpoland.pl (192.168.1.201) appears to be up. Host cad202.inpoland.pl (192.168.1.202) appears to be up. Host cad204.inpoland.pl (192.168.1.204) appears to be up. Host cad209.inpoland.pl (192.168.1.209) appears to be up. Nmap run completed--255 IP addresses (12 hosts up) scanned in 7.256 seconds Fig. 3: Sample of crontab command. 1-56/5 * * * * root /usr/bin/nmap -sP 192.168.1-255 >/var/log/activeresources.txt Fig. 4 Sample transformation command cat /var/log/activeresources.txt [absolute value of grep appears] wc -1 Fig. 7. Sample transformation command--grep single resource cat /var/log/activeresources.txt [absolute value of grep192.168.1.2] wc -1
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|Author:||Fabisiak, B.; Zasada, M.|
|Publication:||Annals of DAAAM & Proceedings|
|Date:||Jan 1, 2005|
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