This paper will address
- Knowing when to do a pH sensor calibration versus a calibration check
- How to properly clean a pH sensor
- How to perform a pH sensor calibration
- A decision tree for step by step guidance
The phrase in the above title is actually incorrect in its sequence of wording. All pH readings are supposed to be taken and accepted only when the pH sensor is clean. After all, a contaminated pH sensor may yield an incorrect reading. So one must make sure the sensor is clean before doing a calibration. Once a pH sensor is installed in the process and operating, how do you determine when it is time to take the sensor out of the process and do a cleaning, or a calibration? Does one perform both a cleaning and a calibration or just a cleaning, or just a calibration, or does one just perform a calibration check in buffers or...?
This is something that can be quite confusing, especially when the operational practices and procedures documented by your company's Quality Control or Environmental Practices department may not be specific enough when they describe the procedure or the timing on when to conduct the pH calibration and maintenance. Inversely, the procedures may be too specific, detailing many more procedures and operations than are actually required.
In practical terms, users must develop their own maintenance and calibration schedule. This schedule is accomplished by taking the pH sensor out of the process after a set amount of time, perhaps after a day or two to perform a visual inspection of the sensor. If after inspection you find no debris or fouling on the electrode and reference surfaces with the naked eye, rinse the sensor off in distilled water and perform a buffer check.
Your control system is keeping secrets from you. The DCS, PLC and historian have a huge amount of data from your plant. But they are not telling you the most important secrets that lie within. Learn how to uncover the secrets to save energy, increase production and improve product quality.
There is an upside for forward-thinking manufacturers regarding EPA blueprint for the way state and local regulatory agencies use the Clean Air Act permitting process to regulate greenhouse gas emissions in the United States.
U.S. Environmental Protection Agency blueprint for the way state and local regulatory agencies use the Clean Air Act permit process to regulate greenhouse gas emissions in the United States is defined in their November 17 document: PSD and Title V Permitting Guidance for Greenhouse Gases.
The greenhouse gases that will be regulated include carbon dioxide, methane, nitrous oxide, sulfur hexafluoride and a number of refrigerants.
The Agency believes that these compounds are responsible for changing the planet's climate and is thus taking steps to reduce emissions of the gases throughout the nation. In taking this action, EPA is breaking new ground, by not only defining a broad new class of air pollutants, but by changing the way that the Agency regulates emissions of those pollutants.
Traditionally, EPA has set definitive, measurable goals when seeking to reduce air pollutant emissions, both in terms of how much a compound a facility is allowed to emit and in terms of the maximum amount of the pollutant that can be in the air we breathe. The Agency will not take the same approach when it comes to greenhouse gases. Instead, they will be asking facilities to reduce emissions to the greatest extent possible and economically feasible.
And, yes, there is upside for forward-thinking manufacturers.
Portal technology is invigorating todays corporate environments. The business world began to take portal technology seriously when the price to acquire start-up portal sites, such as My Space and Flickr, exceeded all anticipated market values. Today, portals are big business. Corporations ranging from SAP to Microsoft are investing millions of dollars in portal technology. New technology frameworks and architecture have changed the direction of portal solutions from recreational portals to the enterprise. Networking technology enables users to access portal-based web sites from anywhere and through any device that can connect to the internet. The purpose of this paper is to help you determine how your company can benefit from a portal environment, and from the OSIsoft suite of visualization components. For the first time, you can combine data stored in PI with enterprise systems and other data sources into easily accessible information, visible to individuals, teams, sites, and the enterprise.
Balluff experts explain the three fundamental qualities that determine if RFID systems will perform reliably in demanding production environments. It answers three main questions: Will the RFID system integrate seamlessly with industrial control systems? Will it provide the reliability and speed that production and information systems require? Can it maintain uptime and performance long-term?
The Surge-Trap is a branded surge protection device (SPD)that utilizes Mersen's patented thermally protected metal oxide varistor (TPMOV) technology. This technology eliminates the need for fuses to be installed in series with the Surge-Trap SPD.
which saves money and panel space. Surge-Trap SPD is typically installed in industrial control panels to protect sensitive electrical equipment from harmful voltage transients. Nearly 80% of all transients are caused by equipment or power disturbances within a facility.
What Types of Ratings Do SPDs Have?
Do SPDs have a current rating? This is a trick question! They do not have a continuous current rating however they do have other important current-based ratings. They are required to have a short circuit current rating (SCCR), which is the maximum rms current at a specified voltage the SPD can withstand.
The nominal discharge current (In) is new to UL 1449 Third Edition (effective 9/29/09). This is the peak value of the current (20kA maximum) through the SPD (8/20μs waveform) where the SPD remains functional after 15 surges.
There are two main voltage ratings for an SPD, the first is maximum continuous operating voltage (MCOV) which is the maximum rms voltage that may be applied to the SPD per each connected mode.
Voltage protection rating (VPR) is determined as the nearest high value (from a list of preferred values) to the measured limiting voltage determined during the transient-voltage surge suppression test using the combination wave generator at a setting of 6kV, 3kA.
For decades, process instrumentation specifiers have faced the decision whether to use a mechanical switch or a continuous transmitter for a given application. Either type of instrument can be used to effectively control industrial processes and protect equipment and personnel -- and each has associated pros and cons. Application specifics typically drive decision-making, dictating which approach is most effective from performance, cost and lifecycle support perspectives.
This paper provides background on, and an overview of, the soon to be released WBF XML batch and enterprise-control system schemas. The schemas consist of two sets, one is intended to provide for the exchange of batch data and is based upon the ANSI/ISA 88 standard. The second is intended to serve as a basis for exchanging data between enterprise and control systems and is based upon the ANSI/ISA 95 standard. The organization of each set is described along with examples on how they can be used.