The CHATEAU Central Heating Controls

Press DAY to start. See bottom of page for questions and explanation of what it's about.

 

M T W Th F S Su
  time:   prog:  
   

 

 

Summary Instructions

This devices stores 16 memories, 8 for turning ON and 8 for OFF. Each memory records the time to act, and the list of days when it should act.

Use button P ('programme') to select which memory to set; use button Day to select the day or group of days on which it should operate; use Hr and Min to set the time when it should operate.

Set up the programmes in turn. Each time you press P the device will store the settings for day(s) and time in the currently chosen memory, and it will then move on to the next programme and show you the stored settings.

 

Memories can be changed independently.

The R ('reset') button clears everything in the memories.

Here's a helpful example - if you press the button, it will program the controller to the same times as the 'Alhambra' defaults

Manufacturer's Instructions

How to check your programming:

press the 'show events' button. NOTE that this is not part of the original device.

Questions

    1. Which of the 5 generic activities best describes typical interaction with a central heating controller?
    2. What is the notation of the main device?
    3. How does this controller rate on the dimensions of viscosity and abstraction level? (Compare it to the Alhambra model and the Balmoral model.)
    4. What abstractions are available? are they transient or persistent? is there an abstraction management sub-device? Does it impose a need for lookahead to avoid premature commitment?
    5. How does it rate on visibility and hidden dependencies? Compare it to the Alhambra model.
    6. How does it rate on closeness of mapping, compared to the Alhambra model?

"What's all this about?"

I have set up this virtual device, and a number of others, to illustrate the 'Cognitive Dimensions' framework. (If you don't know about the framework, you can look at a brief introduction or a full-length tutorial.) By comparing alternative designs for the same purpose, you can see how the framework helps to understand the pros and cons.

At present there are other examples of heating controllers, an example of a telephone (more to come), and two examples of menu selection.A three-button watch and a two-button pager are nearly finished.

Some of these devices may raise usability issues that go beyond the cognitive dimensions framework. For really keen head-scratchers, look also at Ontological Sketch Models (somewhere on my work pages). The Cognitive Walkthrough is an alternative evaluation method, or, coming from a different direction, try Thimbleby's state-space analysis.

The original device is the Potterton PUMA Electronic Timer Pack, pt no 27/19168-02, mnfrd by Potterton Myson, Myson House, Rugby, Warwickshire CV21 3JH. (Photograph to come.)

Thomas Green; , home page

December 1999