What is the Pressure on the Rosemount 1151?
The Rosemount 1151: The Basics
Think of the Rosemount 1151 as a reliable translator. It takes a physical force—pressure—and turns it into an electrical signal (usually 4-20 mA) that your control system can understand. Its main job is to measure differential pressure (DP). This means it doesn’t just give you one pressure number; it compares the pressure on its “High” side to the pressure on its “Low” side and tells you the difference.
This is super useful for things like:
Flow Measurement: When fluid flows through an orifice plate, it creates a pressure drop. The 1151 measures that drop, and you can calculate the flow rate.
Level Measurement: In a tank, the pressure at the bottom relates to the height of the liquid. The 1151 can compare this pressure to a reference (like the top of the tank) to find the level.
Filter Monitoring: It can tell you if a filter is clogged by measuring the pressure difference across it.
It’s All About the Range
When you ask about the pressure on it, you’re really asking what pressure it’s measuring. The key is the calibrated range. The Rosemount 1151 isn’t one-size-fits-all; it comes in many models with different ranges, like 0-5 inches of water column (inH₂O) all the way up to 0-2000 pounds per square inch (psi).
So, the “pressure on your 1151” is whatever falls within its specific range. You can’t put 1000 psi on a model made for 10 psi—it won’t work.
Absolute, Gage, or Differential? It Knows the Difference.
While famous for DP, the 1151 family has variants:
1151DP: The standard for differential pressure.
1151GP: For gauge pressure. This measures pressure compared to atmospheric pressure (like your tire gauge).
1151AP: For absolute pressure. This measures pressure compared to a perfect vacuum.
The model you have directly answers the “what pressure” question.
Why Installation Matters
Here’s a biggie: the static line pressure (the actual force in your pipe) matters a lot for the 1151. Even if it’s only measuring a small difference, its body must be rated to handle the full system pressure. Always check the nameplate for the maximum working pressure.
Common Issues That Affect the Reading
If the pressure reading seems wrong, don’t blame the range just yet. Check for:
Zero Shift: Is the transmitter reading pressure when there shouldn’t be any? This might need a re-zero.
Clogged Impulse Lines: The tiny tubes connecting it to the process can get blocked, giving a false reading.
Moisture or Damage: Water in the housing or a damaged capacitor cell can cause drift.
The Bottom Line
So, what is the pressure on the Rosemount 1151? It’s the differential, gauge, or absolute pressure it was specifically calibrated to measure within its defined range. Its value lies in its ruggedness and accuracy for a huge variety of industrial applications.
Before you buy or calibrate one, know your process: What’s the minimum and maximum pressure difference you expect? What’s the maximum system pressure? Answering these will tell you exactly which 1151 you need and what pressure it will show.
Got a specific Rosemount 1151 scenario you’re dealing with? Browse our site for more detailed technical guides and support to keep your process running smoothly!