THE CLIMATE CONTROL COMPUTERSYSTEM AT THE IMAG, WAGENINGEN

The development of the humidity deficit controller on the IMAG institute ten years ago, a controller that was produced very soon by several firms in order to be used by practical growers, and after additional developments in the area of controlling water supply, screens and so on, it was a logical consequence to develop a computer to control the complete climat in greenhouses.
For this reason the first computer was already put on the budget in 1970 but it was rejected then.
In 1974, however, a new proposal was honoured and one year later the computer was installed.
Three IMAG engineers spent half a year each to develop the control software, which was basically a translation of the analog controllers.
Each greenhouse was connected to the computer by a number of thermocouples using for each couple a relative expensive amplifier, and some analoge sensors directly connected to a multiplexer that was a part of the computer hardware.
The output to each greenhouse was specially constructed by an IMAG engineer, with for each control output a relay and a lamp.

Very soon the occupation of this stand alone computer system was equal to 100%, because more and more researchers discovered the advantage of working with a computer.
For this reason and because of the expensive hardware and because the IMAG gardener personal wanted to have a central room for measuring and controlling all the greenhouses on the IMAG premises, did IMAG decide on the development of a new system.

The system had to meet some requirements:

1. The new system should have the tools, needed for the development of new algorithms.

2. The new algorithms should be tested by means of easy to install software modules, whilst using them in a normal greenhouse control loop.

Symposium on Computers in Greenhouse Climate Control

W.Th.M. van Meurs

https://doi.org/10.17660/ActaHortic.1980.106.10