[email protected] | Installation manual Omnicomm 2.0 terminals v2.2
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APPENDIX D
Description of operating principles for universal inputs of Omnicomm2.0 Terminals
Universal inputs can be connected to one of three types of sensors:
• with analog output voltage signal;
• with impulse (frequency) output signal;
• with potential signal.
Analog voltage output signal
is a signal in which the measurement sensor is proportional to the voltage
at its output. The higher the voltage, the greater the measured value (which is called directly proportional
to the signal) or the lower the voltage, the greater the measured value (the inversely proportional signal).
The Omnicomm Terminal can work with either directly proportional, or inversely proportional, to the signal.
The analog sensors can be classi
fi
ed as sensors that have no output signal voltage and current signal (the
most common signals being 4–20 mA and 0–20 mA). To connect the sensor to the Omnicomm Terminal,
you need to install a bypass resistor and measure the voltage drop on the Terminal (i.e. the signal current is
converted into a voltage signal perceived by the Omnicomm Terminal).
Analog voltage signal is measured by Omnicomm Terminal and is converted into a physical quantity
measured by sensor. Conversion is performed according to a linear law given by two points when
con
fi
guring the Omnicomm Terminal.
FIGURE 48. ASSIGNING THE LAW OF CONVERTING VOLTAGE INTO THE VALUE
OF THE MEASURED PHYSICAL QUANTITY
The average measured value obtained during the period of data collection and converted based on the
linear law is transmitted to Omnicomm Online.
Note: The Omnicomm Terminal collects data and transfers it to Omnicomm Online once during a given
period of time. Data collection period is speci
fi
ed during con
fi
guration of Omnicomm Con
fi
gurator with
the parameter that carries the same title.
Impulse (or frequency) signal
is a signal in which the result of measurement is modulated by frequency,
i.e. the greater the result of the measurement, the greater the number of impulses per unit time. For
impulse signal type, Omnicomm Terminal adds together the number of impulses (along the front, i.e. along
the front of the increasing signal) for the data collection period, multiplies the amount by the calibration
coe
ffi
cient of the impulse input and transmits the result to Omnicomm Online. Multiplication by calibration
coe
ffi
cient is needed to convert the number of impulses into the value of the physical quantity, measured
by sensors (for example, converting the number of impulses into engine rotation speed).
