One of the first operations you should perform on a clock or watch is to put it in beat. The rate can change if a timepiece is out of beat, so it should be put it “in beat” before rating it. A timepiece is in beat when the even and odd beats are of equal length, but the even and odd beats will almost never be perfectly equal.
To measure beat error you must use the acoustic sensor.
When MicroSet measures watches it displays the beat error as a number of milliseconds. This is the traditional measurement used with watch timers. In this example MicroSet shows us a beat error of 4 milliseconds. In other words, one tick is 4 milliseconds longer than the next. You will have to decide how much beat error you are willing to allow.
When MicroSet measures the beat error of a clock, it shows you the percentage of difference between the even and odd ticks. If the ticks are perfectly equal, the percentage of difference is zero. If one beat is a little longer than the other, there will be some percentage of difference between the two beats. For example, a clock might show a beat error of 10 percent. This means one beat is 10 percent longer than the next beat. If you can adjust the beat error to less than 10%, you’re in good shape. In this example, the clock has a beat error of three percent.
We use percentage of error with clocks because the rates of clocks vary so much. An error of 10 % in a clock with a beat time of 10,000 BPH is 36 milliseconds, but an error of 10% in a clock beating 3600 BPH is 100 milliseconds. By comparing the beats as a percentage you don't have to think about the actual beat time of the clock. A clock that beats slower can tolerate a longer beat error because it's a smaller percentage of the beat time.
MicroSet shows the beat error with a plus or minus sign. This sign tells you which side is longer. A plus sign means the first beat is longer, a minus sign means the first beat is shorter. The first beat is the first one measured after you press BEGIN to start the Beat Error Mode.
When you use the Beat Error Mode on clocks, you’ll find that the value is constantly changing. This is because there are almost always imperfections in the escape wheel. You are likely to find that the beat error of a clock cycles through a range of five or six percent during each rotation of the escape wheel. The goal with MicroSet is to set the clock so the beat error ranges by the same amount between positive and negative values. This means the beat is centered around the point of being perfectly in beat.
Revision date: 10-17-03
