Precision, multi-channel data acquisition. Temperature-focused menu selections make the 2638A especially suitable for temperature validation applications.

Fluke Hydra III
Key features
- DC accuracy of 0.0024 %
- Thermocouple accuracy of 0.5 °C
- Up to 66 universal differential isolated inputs
- On-screen colour trend graphing of up to four channels at a time
- Easy-to-use menu system for setup and data management
- Input types: ac V, dc V, ac I, dc I, thermocouple, PRT (2, 3, 4 w), thermistor, resistance (2-4 w), frequency
- Multi-channel real-time data display
- 6.5-digit bench DMM function for front-panel inputs
- Monitor function for real-time viewing and charting between scans
- 20 on-board math channels
- One-button screen capture of chart or data displays
- 45 channels/second basic dc scan rate
- 12 channels/second thermocouple scan rate
- Internal 57,000 scan/setup file memory
- USB flash drive support
- Data security features
- 300 V CAT II input safety rated
- Supported by TQSoft and TQAero thermal validation software for FDA 21 CFR Part 11 and AMS 2750 compliant data collection
The Fluke Hydra Series III continues the Hydra Series legacy of precision, multi-channel data acquisition. The new Series III improves on Hydra's industry-leading thermocouple accuracy and adds a new dimension to how you collect and view data in a portable system.
DC measurement accuracy of 0.0024 %, basic 0.5 °C thermocouple accuracy, full-colour display, easy-to-use menu system and industrial safety ratings put the 2638A in a category of its own as a precision data acquisition system. The dedicated 6.5 digit digital multimeter (DMM) mode provides additional utility and value.
The 2638A is expandable from 22 to 66 channels of differential analogue inputs. A flexible, 22-channel Universal Input Connector lets you connect and disconnect any type of input to any channel, quickly and easily.

Selection Guide
INPUT | RANGE | RESOLUTION | ACCURACY (3-Sigma)¹ |
---|---|---|---|
DC Volts | 100 MV to 300 V | 0.1 µV to 1 mV | 0.0024% |
AC Volts | 100 mV to 300 V | 0.1 µV to 1 mV | 0.11% |
Resistance | 100 Ω to 100 MΩ | 0.1 mΩ to 100 Ω | 0.01% |
Frequency | 20 Hz to 1 MHz | 0.01% | |
RTD (Pt100) | -200 °C | 0.001 °C | 0.016 °C |
Thermocouples | |||
J | -200 to 1,000 | 0.01 °C | 0.53 °C |
K | -200 °C to 1,000 °C | 0.01 °C | 0.60 °C |
T | 270 °C to 400 °C | 0.01 °C | 0.62 °C |
Other Thermocouple types R, S, N, E, B, C, D, G, L, M, U, W |