AutoGRAPH ON-BOARD CONTROLLER • USER MANUAL
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TechnoKom © 2016
RPM Input
AutoGRAPH-GSM+, AutoGRAPH-GSM+WiFi and AutoGRAPH-WiFi controllers are equipped
with one RPM input: pin 23 on the 6-pin RS-232 / RS-485 / RPM / Input 9 connector
The RPM input of the controller is intended to measure a rotating frequency of different
actuating mechanisms.
Input frequency ranges from 0,01...10 000 Hz (0,6...600 000 rpm).
Accuracy of frequency measuring – 0,01% (but not accurate than 0,01 Hz (0,6 rpm)).
AutoGRAPH controller is able to measure and record RPM readings, as well as monitor a
threshold value of RPM readings enabling preset actions in case of the threshold crossing. It
can be extra data transmission to server, SMS or call to specified number, and an extra record
of RPM readings.
RPM readings can be recorded with a regular period or in adaptive basis providing that data
is recorded if RPM level changes more than the Maximum level of changing per a unit of time.
To record RPM data in required units, there is a coefficient multiplying reading by before
recording in the tracker memory.
Given below is an example of measuring the rotating frequency of a crank shaft. This requires
that the RPM input is connected to a phase winding of the generator (usually denoted by “W”)
or an output of AC voltage with a frequency proportional to rotating frequency of the actuating
mechanism.
Following formula is used to recalculate frequency value on the RPM input to a number of
revolutions:
You can configure RPM threshold and the conversion coefficient in the AG.GSMConf software
intended to set up operation parameters of AutoGRAPH on-board controllers. Detailed information
is given in document “Configuration and setup. AG.GSMConf software”.
i
NOTE
where
n – a number of engine revolutions;
f – frequency of voltage on RPM input;
p – a number of pairs of poles (e.g. p=6 for the most of vehicle produced in Russia);
i – gear ratio;
This formula can be used only when the RPM input of AutoGRAPH tracker is connected to a
phase winding of the generator. Because the conversion coefficient depends on how the RPM
input is connected to rotating mechanism.
IMPORTANT
60 f
p i
n=
