plus Firmware.
On AC-CDI v7.9, DC-CDI v7.9 or DC-CDI v2.1 the tacho output available at RB5/PIN11/TP1 can drive a tachometer.
The signal is a +5volts level and 5% Duty Cycle signal:
but some tachometers need a +12v level at 50% DutyCycle signal !
In order to work with such tachometers I created a small microprocessor able to convert the Duty Cycle while keeping the same frequency.
Characteristics | Min | Typ | Max | Unit |
Output Duty Cycle | 50 | % | ||
Input Duty Cycle | 0.1 | 99.9 | % | |
Input Voltage | 2.5 | 5 | V | |
Output Voltage | 5 | V | ||
Frequency | 5 | 800 | Hz | |
RPM | 30 | 48,000 | RPM |
Working:
The processor convert the input signal to an even 50% ratio.
A +5v level 50% DutyCycle is available at pin2, then a NPN transistor raise the signal to a +12v level.
Extend 0.1% DutyCycle at 8Hz:
at 800Hz:
or shrink a 99.9% DutyCycle signal:
Schematic:
Hi is the software for the tacho drive circuit available without buying a microprocessor?
Hi,
Yes at: https://transmic.net/product/dc_12f629_firmwarefull/