Fluke 5626 Secondary Standard PRTs

The Fluke 5626 Secondary Standard PRTs are high-temperature secondary standards that fill the gap between affordable, but temperature-limited secondary PRTs (platinum resistance thermometers) and more expensive, highly accurate SPRTs (standard platinum resistance thermometers).

The Fluke 5626 is nominally 100 Ω and the 5628 is nominally 25.5 Ω. Both instruments have a temperature range of –200 °C to 661 °C. They make great working or check standards for calibration work up to the aluminum point. This article will provide an overview of the Fluke 5626 Secondary Standard PRTs, their key features, and their specifications.

Key Features

The Fluke 5626 Secondary Standard PRTs are designed to meet all ITS-90 requirements for resistance ratios. They have an RTP drift of less than 20 mK after 500 hours at 661°C. The calibrated accuracy of the Fluke 5626 is ± 0.006 °C at 0 °C. The 5626 and 5628 are designed to reduce the contamination risk through the use of internal protection while not impairing performance.

The 5626 Secondary Standard PRTs are ideal for applications where block calibrators, furnaces, or temperature points are being used above normal PRT temperatures. They have a temperature range of –200 to 661°C, higher than most PRTs. With internal protection, the thermometer helps reduce the risk of contamination. The Fluke 5626 Secondary Standard PRTs are available in different sizes, including 12, 15, and 20 inches. Custom lengths are also available on request.

Fluke 5626 Secondary Standard PRTs Specifications:

• Temperature Range: −200 °C to 661 °C
• Rtp: 100 Ω ±1 Ω at 0.01 °C
• Resistance RatioW(Ga):
  • W(302.9146K) ≥1.11807
  • α ≥ 0.003925
• Calibration Uncertainty (k=2):
  • ±0.006 °C at −200 °C
  • ±0.004 °C at 0 °C
  • ±0.009 °C at 420 °C
  • ±0.014 °C at 661 °C
• Short-Term Stability: ±0.003 °C
• Long-Term Drift (Rtp): ≤ 0.03 °C with 500 hours at 661 °C
• Sheath: Inconel 600
• Handle Temperature Range: 0 °C to 80 °C
• Lead Wires: 4-wire Super-Flex PVC, 22 AWG
• Termination: Gold-plated spade lugs
• Size:
  • 304.8 mm x 6.35 mm dia. (12″ L x 0.25″)
  • 381 mm x 6.35 mm dia.(15″ L x 0.25”)
  • 508 mm x 6.35 mm dia. (20″ L x 0.25″)