On-Line Data Logging for NPK Plants

Keywords: Data logging computer, Fertiliser manufacture, Process control.

In 1975 a Paper was presented to the Society about an Off-Line Data Logging System. This paper continues the story from then onwards. The starting points were the disadvantages of an Off-line system, and the costs of running computing on an external bureau. Similarly an alternative to a bureau was sought for Technical computing where Fortran programs were extensively used. A micro-computer – the Wicat – was found which could run full ISO Fortran programs. A small Wicat was purchased for Technical computing, and some of the calculations done on the NPK Plant were run on this machine. This developed into some limited data logging. It was then realised that the whole of the NPK Off-line data logging system could be transferred to a microcomputer.

A system design was prepared for logging the Chemical Analyses, Sieve Analyses and Control Panel Readings on the Wicat 150 microcomputer, which became used exclusively for NPK Plant Data. Data is entered in the control room via the keyboard, though consideration was given to alternative means of data collection. The initial program design was based very much on the Plant Log Sheets which had preceded them, with retrieval programs similarly matched. Initially there were some programs for preparing reports including graphs and statistics. There was also a program for logging production statistics based on plant integrators and down time records.

The second phase of the development saw improvements being made to the Plant mass balance program which is used for formulation control, and this has become the standard way of plant control with consequent significant financial savings. Other programs have been developed for giving various management reports, and for handling all the variable cost reporting and budgeting.

The Wicat 150 was replaced by a Wicat 155 (and subsequently a Wicat 1260), and the whole system expanded to a plant information system, where information on training, the plant diary, and lubrication schedules are kept. Because of the flexibility and approachability of the Wicat operating System, many people on the plant have been able to develop and use the computer with good result.

The system continues to develop, with links to an Automatic NPK analyser recently being commissioned and the conversion of the Wicat 155 to a training computer for running computer-based training packages.

I K Watson and D W Phillip, UKF Fertilisers Ltd., Ince, Chester, UK.

39 pages, 12 figures, 2 refs.