Overview
Applying the DX's mathematical functions, humidity is calculated using the dry bulb and wet bulb formulas based on input from a resistance temperature detector (Pt). The calculation follows the Perunta formula.
Customer Needs
- To have the humidity calculation function be internal to the DX, since we want to monitor humidity along with the internal temperature of the environmental testing equipment
- To use general purpose RTDs rather than specialized humidity sensors, and avoid depending on external instruments and complicated programming
Process Outline
Signals are input from Pt type RTD sensors. Dry and wet bulb temperature are measured with the Pt's, and the DX's calculation function automatically calculates humidity based on the measured values. The calculation is based on the Perunta formula, and the multipliers in the formula are input ahead of time as Kxx. Dedicated humidity sensors or external computing units are not needed to determine the humidity, resulting in reduced costs and more compact instrumentation. The number of instruments comprising the system is also reduced, resulting in higher overall reliability. Sensors can be hard to calibrate due to the difficulty of creating a reference humidity. The DX overcomes this problem because humidity is determined through a calculation, and calibration of the input can be substituted with calibration of the Pt100ohm range.
| Input: | Pt100 (or JPt100) |
|---|---|
| CH1: dry bulb°C), CH2: wet bulb°C) | |
| Computed result: | Humidity displayed on CH37 (MATH channel) |
| Expressions and constants: | Perunta formula |
| 31: | 1+K9 |
| 32: | 2+K9 |
| 33: | EXP(K1/31+K2+K3*31+K4*31*31+K5*LOG(31)) |
| 34: | EXP(K1/32+K2+K3*32+K4*32*32+K5*LOG(32)) |
| 35: | 33*K10 |
| 36: | 34*K10 |
| 37: | ((36-K6*K7*(K11+2/K8)*(1-2))/35)*K10 |
| K01: | -6096.9 |
| K02: | 16.636 |
| K03: | -0.027112 |
| K04: | 1.674E-5 |
| K05: | 5.6033 |
| K06: | 0.0012 (ramda) |
| K07: | 1.0133E+5 |
| K08: | 610 |
| K09: | 273.15 |
| K10: | 100 |
| K11: | 1 |
| K12: | 2 |
| K06 (ramda) value is set as follows | |
| When wind speed is 0-0.5 m/s: 0.0012 | |
| When wind speed is 1-1.5 m/s: 0.0008 | |
| When wind speed is 2.5 m/s or higher: 0.000656 |
Yokogawa's Solution
DX Series Paperless Recorders can easily calculate humidity using RTDs
- Humidity calculated with a MATH function (optional)
- Measured and calculated results saved electronically to local media while being displayed in real time on the large, color TFT display
- Enables data sharing on the network (Ethernet compatible)
Conclusion
 |
| DX |
DX series instruments allow you to determine temperature and humidity and manage the results as manufacturing/quality data at a reasonable cost with a simple configuration. No special external equipment or humidity sensors are required, resulting in overall cost reductions in the system.
Industries
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En mer
L'exploration et la production offshore exigent un temps de fonctionnement maximal dans des conditions difficiles. Les installations avec ou sans personnel ont besoin de systèmes intégrés de contrôle et de sécurité (ICSS) fiables avec des capacités de surveillance à distance avancées. Yokogawa dispose d'une technologie de pointe et d'une grande expérience dans l'exécution de projets offshore de toutes tailles et de tous niveaux de complexité d'automatisation.
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Exploration et Gaz
L'industrie en amont comprend des activités offshore et onshore, notamment l'automatisation des têtes de puits, le fractionnement, la complétion et la séparation pour récupérer et préparer le pétrole brut et le gaz naturel souterrains ou sous-marins.
Lorsque le pétrole est ramené à la surface, il doit être séparé avant d'être transporté. Les étapes de séparation primaire et secondaire distribuent généralement le flux de gaz, le flux d'eau et le flux de pétrole dans une séparation en trois phases. Le transport du gaz nécessite un gazoduc et peut inclure un processus de fractionnement en amont avant le transport. Les liquides peuvent être placés dans des réservoirs ou des pipelines et envoyés pour traitement, ce qui nécessite des mesures de niveau précises.
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Pétrole et Gaz (exploration et production)
Yokogawa possède une grande expérience dans tous les domaines du pétrole et du gaz, des installations offshore et onshore aux pipelines, terminaux et opérations en eaux profondes. Nous fournissons des solutions qui améliorent la sécurité, garantissent un fonctionnement précis et fiable et augmentent l'efficacité des installations.
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