Rat Rig Community [Unofficial]•9mo ago

Tach is not reading correctly at high speeds

I am using the Delta FFB0412UHN-SM36 fan for part cooling. It works well, but the tach isn't working correctly once RPMs exceed 23700 (according to the tach) or so. This occurs at around 93% on the slider. Once I go at or above 94% the rpms report lower values and goes to zero (even though the fan sounds like it is increasing speed). I should also mention I had to use a poll interval of .00001 in order for the tach to work this well. At suggested polling intervals this behavior occurs at much lower slider percentages about 50% or so. Is this a bug?

pin: !fan_part_cooling_pin
max_power: 1.0
cycle_time: 0.00004
off_below: .1
tachometer_pin: ^PG12
tachometer_ppr: 2
tachometer_poll_interval: 0.00001

pin: !fan_part_cooling_pin
max_power: 1.0
cycle_time: 0.00004
off_below: .1
tachometer_pin: ^PG12
tachometer_ppr: 2
tachometer_poll_interval: 0.00001

2 Replies

miklschmidt•9mo ago

No this is just the nature of tachometer signals, it's not always easy to get reliable results on high RPM fans as the poll interval gets very tiny, and the signal from the delta fans aren't the greatest.

billyd•9mo ago

Ok thanks makes sense

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Tach is not reading correctly at high speeds