Does Tachometer need calibration?

[pa38112]

I just replaced my Vans analog tachometer with a MGL rpm-1 unit. I installed a Hall Effect sensor on one mag and also kept the vans sender as a secondary source. I set up the tac for 1 pulse per revolution on the hall input and 4 pulses per revolution from the Vans sender. They both give the exact same RPM readout. Can I assume this is accurate? When I compare to a photo tach that I have the photo tach reads 5% higher, but I would think that 1 pulse per revolution is 1, especially when it matches exactly to 4 pulses per revolution from the secondary input.

[gasman]

Test your photo tach by pointing it at an incandescent household light..... it should read 3600.

[N941WR]

Electronic tacks simply count pulses over a given time. There is usually an averaging routine to smooth the number because our engines bounce around so much. They are generally pretty accurate and don't need adjustment. If one is way off, then it probably has Abad internal click., Which is very rare.

(We developed a tach function for our EICommander.)