Thermal signal calibratorThermal Signal Calibrator is a portable instrument used for calibrating and testing process signals such as temperature, pressure, current, voltage, etc. It is widely used in industrial automation, instrument maintenance, and metrology testing fields. Its core working principle involves signal simulation, measurement, comparison, and correction, which can be divided into the following parts:

(1) Signal generation (analog output)

D/A conversion (digital to analog conversion):

Generate precise digital signals through digital processors such as MCU or FPGA, and then output analog signals (such as 4-20mA, 0-10V, thermocouple mV signals, etc.) through high-precision D/A converters.

For example, when simulating a PT100 resistor, the calibrator will calculate the resistance value corresponding to the temperature and output it through an adjustable resistor or electronic load.

High stability benchmark source:

Using low-temperature drift voltage/current reference (such as LTZ1000) to ensure long-term stability of the output signal.

(2) Signal measurement (input detection)

A/D conversion (analog-to-digital conversion):

Convert the signals output by the tested instrument (such as millivolt signals from thermocouples and 4-20mA signals from pressure transmitters) into digital quantities, and calculate the actual values using internal algorithms.

High precision measurement circuit:

Current measurement: through precision sampling resistors (such as 0.01% accuracy) and operational amplifier circuits.

Voltage measurement: Using a high input impedance differential amplifier to reduce load effects.

Resistance measurement: constant current source method or bridge method (such as PT100 three wire compensation).

(3) Signal comparison and calibration

Closed loop feedback control:

The calibrator compares the output signal with the feedback signal of the tested instrument in real time and automatically corrects errors (such as adjusting the D/A output to match the standard value).

Standard reference source:

Built in high-level standard sensors (such as reference thermocouples, platinum resistors) or external traceability standards (such as Fluke 5520A multifunctional calibrator).

(4) Communication and Data Processing

Protocol support:

Supports communication protocols such as HART and Modbus, and can read and write parameters of smart transmitters.

Data recording and reporting:

Store calibration data and generate reports that comply with ISO 17025 standards.