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Calibrate Pressure With One Hand Using the CPH600

Calibrate Pressure With One Hand Using the CPH600

Next to temperature, pressure is probably the most measured variable in process engineering, using both mechanical and electrical pressure measuring instruments. Based on the application, there are plenty of designs available on the market. With so many options, it is important to remember: pressure measuring instruments need periodic calibration to ensure quality and safety.

Calibrating Pressure Measuring Equipment On-site

While it’s important to calibrate pressure measurement equipment, most pressure instruments do not require the high accuracy calibration achieved in a laboratory. Instead, a portable, hand-held pressure calibrator can be used on-site to perform the service.

Pressure calibration requires the item being calibrated and the calibration standard to be the same pressure. Pressure on site can be generated in a number of ways. External hand pumps can manually generate pressure. Another alternative is a pressure supply case, which uses a cylinder filled with nitrogen. However, a more convenient way to generate pressure is to use a portable pressure calibrator, like the CPH6600. The handy and compact instrument combines a calibration standard and pressure generation, eliminating the need for complex assemblies and providing all you need for pressure calibration in a single instrument. And since fewer connections are needed, there is a lower risk of leaks.

The many functions of the CPH6600 hand-held pressure calibrator

The CPH6600 performs pressure generation, using an integrated pump, in one of two ways: either by manually using a pump handle at the bottom of the instrument or by pressing a button on the built-in electric pump. The unit also features an additional multi-meter function to test transmitters with electrical output signals. The unit measures the current and voltage and includes a 24V voltage supply.

It can carry out pressure switch tests as well. For this, the unit records and displays the pressure on opening, the pressure on closing, and the hysteresis of the pressure switch.

The CPH6600 also measures temperature, which often plays an important role in processes. Connecting an external temperature sensor to the unit can measure ambient and medium temperatures with high accuracy. Handling and operation are simple and user-friendly too. It features a large, easy-to-read screen that can simultaneously display up to three process parameters, which means pressure, temperature, and electrical signals can all be measured at the same time.

Calibrating Pressure Transmitters and Pressure Switches

The CPH6600 is optimally designed for the calibration of pressure transmitters and pressure switches. Follow these steps to calibrate a transmitter with a measuring range of zero to 10 bar:

  1. Connect the pressure-free process connection of the transmitter (via a flexible hose) to the pressure connection of the CPH6600.
  2. Using measuring cables, connect the transmitter output to the CPH6600's measuring channel.
  3. Perform a zero point adjustment, with the vent valve open, by pressing the ZERO button.
  4. With the vent valve closed, set the pressure/vacuum valve to a positive pressure.
  5. Use the integrated electric pump to set individual test points and the fine control to reach the exact pressure setting. A typical calibration consists of five to 10 test points which are distributed uniformly over the entire measuring range. These points are checked with both rising pressure and falling pressure.

To calculate the error on the test item, the CPH6600 has a special feature that instantly displays the deviation of the test item on the display. In the above example, assume the pressure transmitter to be tested has a measuring range of zero to 10 bar and outputs a corresponding four to 20 milliamp signal. The operator can predefine the calibrator with a pressure range of zero to 10 bar, at which point the calibrator calculates and displays the deviation as a percentage of the transmitter's four to 20 milliamp output signal. Consequently, the operator no longer needs to perform error calculation.

Contamination of the Pressure Generation

Since pressure measuring instruments come into contact with different process media in different plants, a dirt trap can be used to prevent contamination by the process media. In most cases, this is a suitable solution for separating the integrated pump from the contaminated calibration item. If the pump becomes contaminated, it can be cleaned through two valves on the back of the instrument.

The CPH6600 pressure calibrator is all you need for pressure calibration. Optimal test intervals and short downtimes for measuring instruments can increase the efficiency of the calibration and monitoring process.