Correspondence testing, making sure that data and wiring are correct so that you know that what you see and control in the control centre matches what is in the real world, is a bit of a bore! It’s also very expensive and very important.
Correspondence testing our model railway, so that when we take it to an exhibition we can check that it has survived the move, is not quite so labour intensive, not quite so important, BUT is equally boring!
Automation is the answer!
You may have seen a previous blog about our ARTIST test tool and wondered what it is/does. Well, here I am going to describe a real life example of an application of ARTIST. Although this is aimed at correspondence testing our model railway, the tool and the principle are equally applicable to ‘real’ railways.
Our model railway control centre consist of the following components:
- Signallers interface providing indications of the state of the railway on a mimic diagram and controls to allow routes to be set and points to be moved, manually;
- An interlocking to maintain the safety of the railway by not allowing routes to be set if they are already occupied and controls ATP codes to stop trains driving into each other;
- A timetable to define the service that the railway runs;
- An Automatic Route Setting module to automatically run and maintain the timetable;
- A serial interface to the model railway controller.
The problem is to check that every indication on the screen corresponds to the correct piece of equipment on the track and that the controls provided effect the correct track equipment. The solution; write a few test scripts, configure the interfaces, connect ARTIST and do it automatically. And redo it until it corresponds!
The interface to the interlocking did require us to write a custom adaptor. Adaptors for more common interfaces, serial, IP, ODBC, already exist. The test script goes through each piece of equipment to:
- Move points;
- Set every signal aspect;
- Set every route;
- Test every track circuit occupation.
The tester is prompted to:
- Confirm that the correct piece of equipment is affected;
- Confirm that the corresponding icon is affected;
- Confirm that the route and route indications are as expected;
- Occupy a track and confirm that the display is correctly updated.
Results are logged and may be printed out in the required format using ARTIST’s print manager. On a model railway this is a fairly simple exercise as one person can watch both the track and the display. However, having developed a script that performs a complete test, it can be rerun automatically in the knowledge that everything is being exercised.
On a ‘real’ railway, the problem of seeing all of the equipment has not been taken away using ARTIST, but making use of a wireless link to a handheld device on the trackside would allow the engineer to see the expected result and confirm its action. Script files can be nested so a complete correspondence test may consist of a number of scripts, each testing one particular item of equipment. Following maintenance of that piece of equipment, the engineer could run the relevant script and check the functioning and correspondence of that piece of equipment, whilst standing next to it!
What you can do is limited only by your (our) imagination. Come and see our model railway correspondence demo at Railtex (Stand C56) and see how ARTIST can help you.