Q1: What type of pressure does the pressure transmitter measure?
A: The first thing to consider is the maximum pressure your system experiences. A good rule of thumb is to choose a pressure transmitter with a range up to 1.5 times the maximum pressure of your system. This is because systems, especially in water pressure and process control, often experience pressure spikes or pulses. These spikes can be five to ten times higher than the normal pressure and may damage the pressure transmitter. Continuous high-pressure pulses that approach or exceed the transmitter’s maximum limit can also reduce its lifespan. Simply opting for a pressure transmitter with a much higher range isn’t ideal, as this will sacrifice resolution. A better approach is to use a snubber to dampen the spikes, even if it slows the transmitter’s response slightly.
Q2: What is the pressure medium?
A: It’s crucial to consider the medium the pressure transmitter will be measuring. Is it a thick liquid or slurry that will come into contact with the transmitter? Will the transmitter be exposed to corrosive substances or just clean air? These factors can determine which type of pressure transmitter is appropriate for your application.
Q3: What level of accuracy is required?
A: Accuracy refers to the transmitter’s output errors, which can result from factors like non-linearity, hysteresis, temperature effects, and more. Temperature changes, zero balance, and other factors can lower a transmitter’s accuracy compared to its nominal rating. While higher accuracy transmitters tend to be more expensive, ask yourself: does your system truly need that level of precision? Using a highly accurate pressure transmitter with a low-resolution instrument is an inefficient and costly approach.
