uThing::iPH
Lab-grade isolated pH & ORP meter with ATC
Description:
uThing::iPH™ is an easy-to-use USB, lab-grade, high-precision, isolated pH and ORP (redox) meter with integrated pH temperature compensation and calibration algorithms.
The dongle is designed for online continuous process pH and ORP monitoring. The voltage input range can be configured for pH or ORP measurements.
Automatic pH temperature compensation can be performed either from an onboard temperature sensor or by connecting the water-proof temperature probe in order to obtain the exact temperature of the liquid to measure.
The integrated MCU coordinates the data acquisition from the isolated analog frontend and the temperature sensors and use the calibration parameters to convert the raw voltage data into precise PH values. These values are then streamed on a configured time interval over a simple Virtual Comm Port (VCP) on the USB connector in various formats (JSON, CSV or "human-readable") for ease of integration.
Very-high impedance analog frontend
pH and ORP probes can have high impedance values in some cases reaching resistances above1 GΩ. Therefore, in order to avoid introducing substantial errors, the input impedance of the measuring system has to be much higher than the probe itself. TheuThing::iPH™analog frontend was carefully designed to have an input bias current as low as20 fA!, or an equivalent input impedance well over theTeraOhmrange, achieving insignificant offset error, even with the most demanding probes (i.e. ±0.2 mV for a 1 GΩ probe).
Key Features:
- High-Precision Measurement: Lab-grade accuracy for both pH and ORP (redox) monitoring.
- Galvanic Isolation: Isolated data and power paths prevent ground loops and protect your host system.
- Automatic Temperature Compensation: Uses an onboard sensor or an external waterproof probe for accurate pH readings at any temperature.
- Very High-Impedance Input: Ensures compatibility with virtually any pH/ORP probe without introducing measurement errors.
- Core Processor: STMicroelectronics ARM Cortex-M4.
- Simple Connectivity: Plugs into any USB host (Linux, macOS, Windows, Android) and works as a standard Virtual COM Port (VCP) with no drivers needed.
- Flexible Output: Provides data in JSON (default), CSV, or a human-readable format.
Sensor Metrics:
- pH (calibrated and temperature compensated) - last measurement
- pH (calibrated and temperature compensated) - average
- Raw Voltage [mV] - last sampling period
- Raw Voltage [mV] - average
- Temperature - on-board sensor
- Temperature - external probe
Output Formats:
JSON:
{"ph":{"last":6.378,"average":6.381},"voltage":{"last":38.21,"average":38.07},"temperature":{"onBoard":23.10,"external":23.31}}
CSV:
[ph_last], [ph_average], [voltage_last], [voltage_average], [temperature_internal], [temperature_probe]
6.378, 6.381, 38.21, 38.07, 23.10, 23.31
Specifications:
- Data reporting rate: configurable between 1 second and 1 hour
- Calibration: 2-points, automatic buffer detection
- Automatic Temperature Compensation: Yes. From on-board or external temperature probe
- Measuring Range:
- pH: 0 to 14.00 pH
- ORP: ±1,650 mV
- Sensitivity:
- ADC: 4uV (pH range), 16 uV (ORP range)
- Reported output: 0.001 pH, 0.1 mV (ORP)
- Stability: 0.01 pH or 1 mV per 24 hours, non-cumulative (*1)
- Input Impedance: > 1 TΩ (1x1012 Ω)
- Input Bias current: 20 fA (typical)
- Temperature resolution: 0.0625°C
- ADC resolution: 18-bit
- Power input: 5V from USB port / 23 mA (115 mW)
- Operating range: -40 <‒> +85 °C, 10 <‒> 90 %r.H.
Connector Type:
USB Type-A Male, BNC for the pH probe, 4-pin for external temperature sensor
Dimensions:
19.8 (W) x 100.2 (L) x 23.5 (H) [mm]
Weight:
24.8 g
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