Yokogawa VI451-10 Communication Module

Current signals: 4-20mA, 0-20mA

Voltage signals: 1-5V DC, 0-10V DC

Thermocouples (TC): Types K, J, T, E, R, S, B, etc.

Resistance Thermometers (RTD): Pt100, Ni100, Ni1000, etc.
The module matches different signal types through internal input selection circuits (such as relays or analog switches) to ensure compatibility when signals are connected.

Filtering: High-frequency interference (such as electromagnetic noise) is removed via RC filter networks or LC filters.

Amplification/Attenuation: Weak signals (such as millivolt-level thermocouple signals) are amplified, while strong signals are attenuated to adapt to the subsequent ADC conversion range.

Linearization Processing: For non-linear signals (such as the thermoelectric potential-temperature relationship of thermocouples), linearization correction is performed through hardware resistance networks or software algorithms to improve measurement accuracy.

Sampling: Analog signals are sampled at a fixed frequency (such as 100Hz or higher).

Quantization: Sampled values are converted into digital codes.

Coding: Binary digital signals are generated and transmitted to the internal processor of the module.

Calibration and Error Correction: Digital signals are real-time corrected using pre-stored calibration parameters (such as zero and full-scale offsets) to compensate for errors such as component temperature drift and non-linearity.

Engineering Quantity Conversion: Digital codes are converted into actual engineering quantities (such as temperature, pressure, flow, etc.), supporting linear or non-linear conversion formulas.

Signal Filtering: Noise is further suppressed through digital filtering algorithms (such as first-order low-pass filtering and average filtering) to improve signal stability.

Overvoltage/Overcurrent Protection: If abnormal high voltage (such as high voltage access due to wiring errors) or overcurrent occurs on the input side, the protection circuit quickly cuts off the input or limits the current to prevent damage to the ADC or other components.

Thermal Protection: An internal temperature sensor in the module real-time monitors the chip temperature, triggering an alarm and limiting output when the threshold is exceeded.

Open Circuit Detection: For inputs from sensors such as resistance thermometers and thermocouples, the module can detect open circuits in the lines and output fault signals (such as fixed values or alarm flags).

Redundancy and Fault Diagnosis: When redundancy configuration is supported, the module can communicate with redundant partners, exchange status information in real time, and automatically switch to the redundant module when it fails to ensure continuous system operation.