Generating/Simulating
64 MC4 User Guide
possible. In this situation, the accuracy depends on the similarity of
the selected sensor in MC4 and the used sensor.
Wire-wound thermocouple temperature indicators and
recorders are calibrated with known loop resistance, commonly ten
or twenty ohms. The required resistance of the conductors is usually
marked on the device. When calibrating such a device, tune the loop
resistance to the nominal value with an additional resistor.
Use MC4's 2-wire resistance measurement to tune the loop
resistance of a wire wound device. Short circuit the measuring
device for the time of resistance measurement. The resistance
measurement may damage the device, if you do not install the short
circuit. For more information on resistance measurement, see
chapter Resistance Measurement on page 47.
Warnings!
If you short circuit the thermocouple simulation output, MC4
tries to maintain the voltage by increasing the output current. If
you then open the output again, the voltage is first too high, but
returns quickly to the correct level. If this voltage peak could
damage the components of the circuit, make sure that the
circuit can not be shorted or protect the circuit against
overvoltage. For the same reason, always enter 0°C output
before connecting the circuit.
If you connect an RTD sensor to the R, RTD connectors, there is
no galvanic isolation between the thermocouple and the RTD
sensor.
Next
Temperature Measurement (Thermocouple) on page 51.
RTD Sensor Simulation on page 61.
Tools Menu on page 67.
Stepping on page 73
Ramping on page 76.
Calibration, see Part D.
Problems with thermovoltage simulation? See Error situations on page 117.
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