Description The M5Stack Kmeter Isolation Unit, also documented on the official sale page as Unit KMeter-ISO, is an integrated K-type thermocouple sensor unit that combines temperature acquisition, signal isolation, and I2C communication. It uses an STM32F030 microcontroller with a MAX31855KASA 14-bit thermocouple digital conversion chip to convert thermocouple data into a host-friendly I2C reading. The Unit KMeter-ISO adds CA-IS3641HW signal isolation between the acquisition side and the communication side, improving stability, safety, and reliability in industrial temperature measurement. It supports K-type thermocouple probes from -200 degC to 1350 degC and uses a standard flat K-type interface so probes can be replaced according to the required temperature range. Features Isolated thermocouple measurement: CA-IS3641HW signal isolation improves safety and stability. K-type thermocouple support: compatible with probes covering -200 degC to 1350 degC. MAX31855 conversion: 14-bit ADC, 0.25 degC resolution, and +/-2% accuracy rating. STM32F030 controller: handles acquisition, processing, I2C communication, and firmware update support. I2C host interface: communicates at address 0x66 for simple integration with M5Stack controllers. Development support: supports Arduino and UIFlow workflows for quick temperature monitoring projects. Specifications MCU STM32F030F4P6 Temperature Sensor Chip MAX31855KASA+T Signal Isolation Chip CA-IS3641HW Resolution 14-bit, 0.25 degC Thermocouple Type K-type Thermocouple Operating Range -200 degC to 1350 degC Standard Probe Range -50 degC to 250 degC, 1m cable length Maximum Sampling Rate 10 Hz SPI Interface Clock Range Up to 5 MHz Internal Temperature Sensor Accuracy +/-2 degC Thermocouple Measurement Accuracy +/-2 degC Fault Detection Open circuit, short circuit, and thermocouple low voltage Communication Interface I2C @0x66 Product Size 56.0 x 24.0 x 8.0mm Product Weight 10.0g Package Size 138.0 x 93.0 x 9.0mm Gross Weight 22.0g Applications Industrial automation temperature acquisition Instrumentation and thermal monitoring Power electronics temperature supervision Heat treatment process monitoring Wide-range K-type thermocouple data logging Product List 1 Unit KMeter-ISO 1 K-type thermocouple probe (measurement range -50 degC to 250 degC, 1m cable length) 1 HY2.0-4P Grove cable (20cm) Other Content The K-type thermocouple sensor unit uses a standard flat K-type connector, making it practical to replace the included probe with another K-type probe when a different temperature range, cable length, or mechanical form is required. Grove Pin Signal Black GND Red 5V Yellow SDA White SCL Before using the isolated K-type thermocouple unit in a control loop, verify probe polarity, expected temperature range, grounding conditions, and the I2C address used by the host controller. Resources Product documentation Arduino library Arduino simple example Arduino graph example UIFlow1 documentation UIFlow2 documentation Internal firmware FAQ What probe type does the Unit KMeter-ISO use? It is designed for K-type thermocouple probes and ships with a K-type probe rated from -50 degC to 250 degC. What is the communication interface? The M5Stack Kmeter Isolation Unit communicates with the host through I2C at address 0x66. Why does this version include signal isolation? The CA-IS3641HW isolator helps separate acquisition and host communication signals, improving reliability in electrically noisy temperature measurement environments.
