Microset Program Sceen
The Microset timer can be connected to your computer, allowing you to view your mechanisms beat on your monitor. The beat pattern shown in this screen shot is from a long-duration Viennese mechanism with a 30-tooth escape wheel and a very light weight. Due to the light driving weight the escapement has no over-swing, which means that even a very slight variation in the length of the escape wheel teeth causes a variation in the beat. I have arbitrarily labeled the peaks as “Ticks” and the lower as “Tocks”. Please realize, I use tick and tock interchangeably, in as much as I am not focused on describing which is associated with the entrance or exit pallet.
Where the wave form expands to its largest extent (like where the labels and arrows for “Ticks” and “Tocks” are pointing) is where the difference between the duration of the tick and tock (the “Beat Error”) is greatest. And in the valleys between these areas (where the two vertical lines indicating the extents of 1 turn of the escape wheel are placed) is where the difference between the tick and tock duration is least – where the beat trace is almost flat on the average beat.
Or, as a correspondent of mine put it: “The graph shows an upper and lower trace, which correspond to the entry and exit pallet locks. The distance between them represents the beat error, and their deviation from a horizontal line shows the variation in either tooth length, escape wheel out of round or offset of the center.”
Our goal is to have a flat line all the way across the plot which would indicate that the tick and tock durations are exactly the same. Probably not possible in the real world but hope springs eternal.
Interestingly, with the way this escapement is set up, the ticks and tocks switch places in the next grouping – but more on that below and in the next slides.
Look carefully at the picture - note the time scale on the left side - with increments of 0.02 seconds. This scale represents the time between a tick and a tock, or, well, a tock and a tick. Looking at the pattern, if you pick any of the upper points, the next point to the right represents the next beat of the clock. So, let’s say the point you pick is just below 0.74 seconds – this tells you that roughly 0.74 seconds elapsed since the previous beat. And, when you find the next beat to the right, it is right around 0.78 – so, 0.78 seconds elapsed since the previous beat.
The vertical axis scale (beat duration) and the center point for the scale can be changed, depending on the mechanism you are working on. I have set the average beat time (0.76 seconds) as the midpoint of the vertical axis. The peaks above the 0.76 average are shorter than the average beat for this pendulum (0.76 seconds) while the valleys (below the 0.76 average) are longer.
As you go from left to right across the graph, each peak or valley is a tick or a tock. So, for this mechanism, there are roughly 240 beats. While it is difficult to tell in this plot, sometimes the tick is longer, and sometimes the tock is longer. Likely you have heard mechanisms that seem to go in and out of beat – this is a plot of that situation. The next picture shows what happens when you go from monitoring both the tick and the tock, to only monitoring one of them.