Having a hard time choosing the right pressure transmitter?
Well, that’s expected considering the many installation locations and applications of pressure transmitters.
Moreover, with the advancement in technology, it becomes more difficult to come up with solid fast rules for choosing the ideal device.
To shed some light on what you should focus on, here are the primary considerations you ought to keep in mind:
1. Operating Environment
Before buying a pressure transmitter, you need to first examine the environment in which the transmitter will operate. This will go a long way into ensuring an extended lifetime of the transmitter. Here are some operating conditions you ought to pay attention to:
For starters, extreme temperatures can impair the accuracy of a transmitter. This includes not only the background temperature of the installation location, but also heat generated from the surrounding equipment.
When subjected to low temperatures that exceed the device’s low range limit, the fill fluids become more viscous. This affects the transmitter’s performance.
To mitigate these problems, you should strive to maintain the temperature of the transmitter. For greatest life expectancy and performance, maintain it at room temperature.
It’s also worth noting that when installing a pressure transmitter in an outdoor setting, you’ve to protect it from direct sunlight and high winds. This will help reduce the heating and cooling effect caused by these atmospheric conditions. This improves the device’s performance.
Also, consider choosing a pressure transmitter designed with stainless steel housing. It’ll offer protection from dust and water.
High humidity causes vapor to penetrate into the electrical components of the transmitter, causing it to short or fail completely. Moreover, the housings and mountings can also last due to prolonged exposure to high humidity.
As a solution to this problem, most manufacturers special materials to protect the electrical components against humidity. But, the solution may not work in the long run which is when choosing a transmitter to ensure it’s sealed from the outside.
Accumulation of vapor can also be due to the temperature difference experienced when measuring cold media in warm ambient conditions. To avoid this, consider creating isolation between the device and the media measured.
Or, you can also choose a pressure transmitter designed to work in environments that are subject to temperature difference.
Vigorous vibrations from the surrounding environment can reduce the lifetime of a pressure transmitter. So, you want to choose a transmitter with a thick housing that can withstand vibration in its area of application.
Additionally, you can also opt to place the transmitter in an area with minimal vibration.
2. Two Wire, Digital or Wireless Options
Pressure transmitters categorized depending on the technique employed to send pressure signals. These categories are digital, wireless and two-way wire type of transmitters.
If your control room is far away from the transmitter’s location, use a two-wire transmitter. It will be less prone to signal interruptions as compared to a digital transmitter. Keep in mind this type of transmitter requires a non-fluctuating current.
A digital pressure transmitter is ideal for use in a place where the accuracy is paramount. The can also the relay voluminous data between the area of installation and the control room.
For faster transmission of data, you may consider the wireless pressure transmitter. It can also relay data over longer distances as compared to the other two transmitters. This makes it suitable for use in hazardous areas.
Given the high installing cost of a two-wire transmitter, wireless devices stand out as a more economical solution.
Wireless transmitters were once subject to interruption in relaying of pressure data. But, improvements have been made to provide an interrupted and secure transmission.
3. Medium Measured
When choosing a transmitter you’ve to ensure that it can withstand the medium you intend to measure.
In most cases, the medium measured is as ideal as clean water or air. But it can be challenging to measure slurry or any other medium containing debris. If not managed properly, clog build-ups affecting the accuracy of the transmitter readings.
Filtering the medium before it reaches the transmitter may seem like a viable option. But, choosing a transmitter with a diaphragm seal is a more practical solution.
The seal helps isolate the medium from the sensitive components of the transmitter. This helps maintain the optimum functionality of the pressure transmitter.
Also, keep an eye on transmitters with large open areas that will resist clogging. Some transmitters have a clean-out port to allow for the removal of material buildup.
4. Performance Requirements
To ensure accuracy, you need to choose a pressure transmitter that’s compatible with the pressure of the medium.
For example, if the pressure falls between the positive and the negative scale, use a compound pressure transmitter. The device is capable of displaying both positive and negative pressures.
Other pressure transmitter measurements include:
This unit is used to measure pressure in a vacuum.
This is the most common type of measurement used in a local atmospheric pressure setting.
Differential pressure unit reflects the difference in pressure between two inputs.
It’s important to note that you can also choose a transmitter with all measurement units in a single device. This will help you cut down the installation costs as well as the need for multiple devices.
5. Safety Integrity
Pressure transmitters are grouped into various classes of safety in terms of their ability to stay functional while maintaining a safe state. These classes are known as Safety Integrity Levels (SIL), and range from 1 to 4, with level 4 being the safest.
But, you don’t need to choose the highest SIL value to guarantee you maximum safety. Consult an engineer to help you choose a transmitter whose SLI value is compatible with the nature of your industry.
Choosing the Right Pressure Transmitter
Picking the appropriate pressure transmitter is essential for the efficiency of your equipment operation, and most importantly, your safety.
To gain a better understanding of how to choose the right transmitter, be sure to follow the guide above.
For more industrial machinery articles, be sure to visit our engineering category.