251 Series {Horizon Line Series}

1 ½" to 4 ½ " Panel meters. High-res. Scales, Ideal for Complicated Scaling
(Reliable tautband or pivot & jewell movement with a basic accuracy of ±2% )


  • Pivot and Jewel or Taut Band models available
  • Basic Accuracy: ±2% of full scale
  • UL models available
  • Expanded Scales available
  • Surface or conduit mounting
  • Surface or window mounting option


  • Standard panel applications
  • Instrumentation – manufacturing component
  • Ideal for adverse (dusty) environments or severe applications, meets UL-1437, IEC 144 or IP54
  • Ideal for OEM and Retrofit applications


251 – Horizon Line analog panel meters are available in a variety of sizes and mounting configurations (front or behind-the- panel mounting)

Our Mod department customizes the meter input and scaling to meet your exact specifications. From dual scaled meters, non-standard distributions such as cosø, log or square root , our dial department can meet your exact requirements. High accuracy meters are calibrated to better than ±1% and if required an optional expanded scale with an accuracy of ±0.5% of full-scale for those applications that require critical readings.

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For process applications, meters can be mechanically suppressed to 4-20 mADC or up to 20% of end scale with an accuracy of ±2% of end scale or better and/or if required meters can be electronically suppressed.

  • Literature
  • Specifications
Model: Yokogawa 251 Series- 1 1/2", 2 1/2", 3 1/2" and 4 1/2" sizes
Scaling: Customized to any scaling desired, from linear to specialized Cos Ø, square root distributions, with color applications for visual emphasis and to any desired engineering units.
Specific Accuracies
Basic Accuracy: ±2.0% of full scale basic accuracy class. **±1% or better upon request
Rectifier Type Meters: ±3% of full scale basic accuracy class. **±1.5% or better upon request
Expanded Scale Voltmeters: 0.5% of full scale
Frequency Meters: ± .15Hz @45-55Hz and 55-65Hz, ±0.093Hz @ 58-62Hz, ±1.5Hz @350-450Hz
Zero Suppressed Meters: Errors at 20% suppression = ±3% of end-scale ***±2% or better upon request
Higher Accuracy: **1% of Full scale or better
General specifications
Position of use: Vertical (scale) standard or to specified angle or position
Full scale deflection angle: 90 °
Full scale length: 11⁄2” 1.50”
21⁄2” 2.06”
31⁄2” 2.88”
41⁄2” 3.93”
Movement: Taut Band
The absence of friction resulting from this permits greater sensitivities and provides more rugged meters. Common failures of conventional meters subjected to shock testing are cracked jewels and/or blunted pivots.
Pivot and Jewel
In this design the coil and pointer are supported by polished steel pivots at each end which fit into jewel bearings. Pivot and jewel meters are recommended for high vibration environments because of the mechanism’s inherent stability and strength. Accuracy and repeatability are almost equal to the taut-band’s, and good performance from the pivot and jewel construction is the reason for its long popularity.
Case: ABS plastic, Black
Cover: ABS cover and window.
Insulation Level: All meters (except 11⁄2”), 2600 Vrms Hi-pot, 11⁄2”-1500 Vrms Hi-pot.
Overload rating: Voltmeters (AC and DC) – 50% momentary, 20% sustained. Ammeters (AC and DC) momentary; 10 times the rated current for 10 consecutive intervals of .5 second with a 1 minute interval between successive applications; sustained:
20% for six hours.
Burden Data: AC Ammeter 5 amps @ 60 Hz, 0.5VA, Max. .5 Power factor lagging, AC voltmeter – unity power factor.
Severe-duty meters: Conform to CSA or UL 1437 requirements in 2-1/2” – 4-1/2” sizes.
Response time: 3 seconds (Max.) – Microammeters
2 seconds (Max.) – All other DC ratings
2.5 seconds (Max.) – All AC ratings
Maximum 40% overshoot
Operating Temp.: 0 to 40°C (32 to 104°F)
Storage Temp: -10 to 50°C (14 to 50°F)
Extreme temperature range:

-20°C to 65°C (-4 to 149°F)
Tropicalized or IP54 sealed units available

Relative Humidity: 95% (non condensing)