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.
Industrias
-
Offshore (FPSO FLNG & FSRU)
Offshore exploration and production requires maximum uptime under harsh conditions. Manned and unmanned facilities need reliable integrated control and safety systems (ICSS) with advanced remote monitoring capabilities. Yokogawa has state-of-the-art technology and extensive experience in executing offshore projects of all sizes and automation levels of complexity.
-
Oil & Gas
Yokogawa has a wealth of experience in every part of the oil and gas business, from offshore and onshore facilities to pipelines, terminals, and deepwater operations. We provide solutions that enhance safety, ensure accurate and reliable operation, and increase plant efficiency.
-
Upstream
The upstream industry includes offshore and onshore activities including wellhead automation, fractionation, completion, and separation to recover and prepare underground or underwater crude oil and natural gas.
As petroleum is brought to the surface, it must be separated prior to transport. Primary and secondary separation stages commonly distribute gas flow, water flow, and oil flow in three phase separation. Gas movement requires pipeline and can include a fractionation process in the upstream stage prior to movement. Liquids can be placed into a tanks or pipelines and sent for processing, requiring accurate level measurements.
Productos y Soluciones Relacionadas
-
Button Operated DX1000/DX2000
The Daqstation DX1000/2000 series is a data acquisition system with display. Its HMI supports custom graphics for industry applications, audit trail and advanced security conforming to FDA 21CFR Part 11.
-
Removable Chassis DX1000N
The DX1000N features a removable chassis via the front panel of the instrument. This allows easy access and maintenance of internal components of the DX1000N.
-
Panel Mount Recorders
Panel mount recorders are fully integrated data acquisition and display stations with secure, built-in data storage and network connectivity. Panel-mount solutions are NEMA compliant and integrate the data acquisition equipment into a control panel.