Honeywell Excel Classic System
This system was introduced in the late 1970's. It is an early DDC system. Although Honeywell had a direct digiatal control technique availabel in their older Alpa/Delta Delta 1000 system, this Excel classicc system was a fully fledged DDC system. It was developed by the Honeywell subsidiary network in Germany. The system was quite simple but clever and expandable. It basically consisted of a control board, and an I/O board and interconnect cabling and an unregulated 24Vdc power supply. One control board could control up to 8 I/O boards. One I/O boared was quite sufficient to control even a large air handling system. The point database for the I/O board was quite simple and allowed easy entry via the operator teminal. Then after the database entry you could program the control action for your air handler or any other control mecahnism via the operatore terminal also. The programming language was actually an improved assembly language called RACL. This language although frightening in its appeance was fairly simple to use. But to really get good at it you would need extensive familiarity. Honeywell also provided several program modules that you could use in your programming and also a large EMS module. But the modules were written more with the ease of their engineers in mind than anything else. The documentation is not straightforward to use and the audience for it is again their installers and engineers. Point/program database can be saved to tape and is also restorable. The sytem does not have EPROM memory so a loss of power can result in point/program datafile loss. But there are capacitors on the controller board to hold the datafiles for upto 8 hours.
CITS has all information on this system and all of its documentation and other tools used to install, service and support this system. CITS can also reapiar all hardweare on this system and has stock for all of its pars. CITS can provide all services for this system including training and reprogrammig it from scratch. This system was later ported to various PC interfaces and to this day there are still hundreds of these controllers out there. CITS can also support the PC front-end that this Excel system was ported to.
CITS Advisory 1
All parts for this system are now obsolete and hence the current stock is not cheap. But CITS has in stock every item for this system. Parts available for this system are searcahable on this website. All items are available immediately. The prices are subject to change without notice for understandable reasons.
CITS Advisory 2
It may appear to that the cost of some tof these items is pretty expensive in some absolute sense but CITS advises that even at the curent prices the items are well worth it since otherwise you will be looking at repalcing the system or upgrading it or you will end up using a lot of time searching for the items. CITS recommends immediate attenstion to your system and offers repair/replacement for everry item in this system in short order. This way you can save tens of thousands of dollars. Please, remember that even migrating just one air handler can cost over 20 thousand dollars if not more. This is because all programs will have to rewritten and new hardwar/wiring installed and new front end used. Please call a CITS engineer to get more information and a recommended path for your migration. Pleae use a safe and economical approach for your site.
In the fianl analysis, use the cuurent system, reapair/service it as long as necessary and produce the money for the replacement for the long run.
Always use a safe and economical approach and not just what is technically available. Because the latter may be exciting but may not be justifiable for your business.