What is lrv and urv

The sensor limits depend mostly on physical restrictions of the sensor. The sensor limits cannot be changed, therefore they are always read-only.

Different sensors have different sensor limits. For example, various RTDs and thermocouples have different sensor limits. In temperature applications, a sensor type with sufficient sensor limits has to be selected to accommodate the range of the application. Since the range limits are physical and cannot be changed, to get wider sensor limits accommodate a wider range, it is necessary to purchase a new sensor.

To get wider sensor limits to accommodate a wider range, it is necessary to purchase a new sensor. For an elevated-zero range, the amount the measured variable zero is above the lower range-value. For a suppressed-zero range, the amount the measured variable zero is below the lower range-value. Range setting is only applicable to transmitter with mA analog output. For mA systems the range is set in both the transmitter and controller.

This also enables DP transmitters to locally indicate in flow or level units. Fig : An analog signal system requires range, current trims, and scaling.

A digital bus system does not. There is also a need to select the desired engineering unit in the device. In control applications, level is usually expressed in percentage of full tank. The output of both the FF transducer block and the AI function block is engineering unit. For most applications there is no need to set range in either block in order to get the PV. However, many systems use the range in the FF transmitter AI block to scale the faceplates bargraphs. A narrower range may optionally be set to increase the resolution of the faceplate bargraph.

Fig : Digital transmitters internally operate in engineering units. Direct numeric value entry means the desired lower and upper range values are simply entered in from device software or handheld field communicator, and sent to the transmitter, for instance, entering the 20 to kPa.

Range setting to applied input requires a physical input corresponding to the desired range value to be applied to the transmitter.

In this example, the zero input value is 0 psig and zero output value is 4 mA. The input span is psig and the output span is 16 mA. MWP refers to the amount of gauge pressure common to each port High and Low , not the differential pressure between ports, that the DP transmitter can safely handle without being damaged.

Transmitter Damping Output function that increases the response time of a transmitter to smooth the output when there are rapid input variations Zero Trim A zero-based, one point adjustment used in different pressure applications to compensate for mounting position effects or zero shifts caused by static pressure.

Email This BlogThis! Share to Twitter Share to Facebook. Labels: Calibration , DP Transmitters. Newer Post Older Post Home. You May Also Like:.