Thin Clients in Manufacturing Environments

Abstract

A plastics manufacturer uses a custom build vb6 application to track production. This is the only application that is needed on the plant floor and the computers need to be secure to prevent un-authorized access to other resources (Internet, games, etc).

Background

Previously this was done with Windows 98 computers locked down with profiles from the domain. Recently the manufacturer experienced 55 inches of water through their operations facility. Luckily the server and general office area is upstairs so none of that equipment was affected. However all 6 computers in the plant were destroyed.

Requirements

The one manufacturing program is needed for each production machine in the plant. A barcode/label printer is needed for each workstation. Also one seperate laser printer is needed. The Barcode printers used are EasyCoder PC4 printers, not exactly industrial strength but for $85/each the price was right and we can replace several printers before reaching the cost of an industrial printer.

The existing server and office workstations were operational so I didn’t want to change anything with the already working operation that might disrupt work with an unproven system. Spending my weekend rebuilting a server that was previously working is not my idea of a good time.

Hardware Solutions Reviewed

NComputing - $230/workstation. This would be a good solution and could have worked. NComputing claims it can run up to 30 workstations from one PC without comprimising performance. They do have the support to really make things happen and are moving from the educational market into the small business community. This is not a true Remote desktop setup. It was a little more expensive than I wanted to spend.

Axel Thin Client - $290/workstation. This would be a true Remote Desktop environment and the test unit I received would support VNC as well as RDP. I am not as sure about the support to get the printers to work on the remote clients.

Off Lease HP 530s desktop computers - $100/workstation. These were standard slimline HP business computers with 256mb, P4, 40gb harddrives, floppy, cd, LPT port. These proved to be the most cost effective solution and if the thin client idea did not work out then they could always be loaded with XP and used as full PCs.

Software

I was looking for a simple piece of software that would run a remote desktop application and provide the support for the local printer on the client. After several hours searching for the a software application to fit the bill I found AnywhereTS and WTware. Both had free versions to try out. The ideal scene was to load the clients from the network however due to the current setup for DHCP (as several more hours of research proved) this was not going to work.

Wtware.com I found on a Tuesday evening and tested it out and determined that it was going to work and was quite disappointed to find the domain expired Wednesday morning. After a bit more research I found that the company is out of Russia and also maintained wtware.ru so an email to support let them know that the domain had expired and they were back up a day later. I have also contacted them on a couple other support issues and they have been very responsive and their existing webpage has a lot of easy to understand examples to get the configurations going.

Downloading and installling Wtware is a simple operation. Once done your choice of media can be choosen to create the boot media. I chose a CD to get started to work ou the proof of concept. The screen was a little confusing when determining were the configuration file was stored for the thin client but once that was understood then things went well. The main thing to know here is that the best way for the system to work is to use the built in tftp server to hand out the configuration files for the clients, this is the ‘get configuration from network’ option. I was able to get this setup and log into an existing XP machine remotely without to much problem. After several more hours of tweaking and understanding the configuration files I found that I could get the system to automatically log on, run a specific application and use a local printer. Wtware was on the only site/software that I found which had the instructions for connecting up a a printer laid out on their site.

There are several pieces of software out there that support providing Terminal Services on XP computers. There is some question about compliance with Microsoft’s Licenses and one could spend a whole lot of time discussing the rights and wrongs however that is not the purpose of this article. The software that I chose was XPUnlimited.com. I have used this before briefly on a couple different projects but this would be the first real live ongoing setup. The cost is $145-$455 depending on licenses and domain requirements but makes the setup of Terminal Services quite easy.

After quite a bit of time researching profile setting to make sure the user on the client computer couldn’t shutdown the main computer and get to the run command the system is pretty tightly setup. The one drawback is that the existing setup doesn’t particularly have a easy override to log in and get to the standard desktop. In order to do this I must change the configuration file back on the server and reboot the client to get access but it sure makes it secure. The only time this will be needed anyway is to change any default settings with the printer or environment settings.

As a note when setting up these terminals each user needed to be unique so they could all be logged in at the same time and each user needed their own default printer and it needed to be set correctly to make sure the labels were set to tear off correctly. This just required the setup to not run the specialized application and I could setup the environment and the reset the configuration file and everything works great.

Future

The plan is to make a virtual machine that supports all of the above including the specialized application so the solution will not be dependant on the one computer upstairs. If something was wrong with that computer then the entire plant would be shutdown. By using a virtual computer that can be ran from different workstations they can just execute the virtual machine from another computer and have the plant back online again.

Due to the effectiveness of this solution and the need/desire to move computer operations to more of a data center environment for backup, support etc. I am considering offering this as a service where the actual system could be rented and all one would need is either a remote desktop or a thin client and they could be up and running.