Integrated on-site induced draft fan vibration measurement sensor JMB35L

pressuretransmitterIt refers to a type of output that is standardizedsignalofpressure sensorStandardized signals refer to signals whose physical quantities conform to international standardization in both form and numerical range. for examplesimulationdirect currentcurrent4-20mA、 The gas pressure of 20-100kPa is currently the commonly used remote transmission standard signal. In addition, domestic pressure transmitters sometimes use a direct current of 0-10mA as the output signal. Regardless of the physical, chemical, or biological input variables of the pressure transmitterparameterRegardless of the input signal value, after passing through the transmitterinformationAll must be included in the standard signal. With a unified output signal format and numerical range, it is easy to combine pressure transmitters and other instrumentsdetectionSystem or regulating system. No matter what instrument or device, as long as there is an input circuit interface with the same standard, the output information of the pressure transmitter can be obtained, and then the input variable information of the pressure transmitter can be obtained. The unified output signal standard of pressure transmitters improves the compatibility and interchangeability of the entire system, making it easy to use.

1. System Block Diagram

The main components of the calibration system includehost computerHardware circuit and pressure of the lower computercontrollerMulti purpose watches, etc. The upper computer communicates with the lower computer, pressure transmitter, multimeter, and pressure controller through four 232 serial portscommunicationAfter installation on the upper computer, the automatic calibration software system can achieve automatic calibration of 32 pressure transmitters. The hardware circuit of the lower computer is connected to the upper computer through a 232 serial port, controlling the free switching of 32 calibration channels. The protocol conversion module of the lower computer part realizes communication between the upper computer and the pressure transmitter. The pressure controller communicates with the upper computer through a 232 serial port, receives pressure control information, and controls the input pressure of the pressure transmitter. The multimeter communicates with the upper computer through a 232 serial port, receives control information from the multimeter, and can send the collected pressure transmitter output current data to the upper computer.

2. Calibration principle

Automatic calibration system for pressure transmitterpower supplyDigital calibration of zero shift and range shift for flow output pressure transmitters. Zero point shift refers to the use of some adjustment method to cause a change in the output value of the pressure transmitter when the transmitter operates at the lower limit of the operating range. Range migration refers to the use of some means to cause a change in the current output range of a pressure transmitter. The principle of calibrating a pressure transmitter is to use the standard value output by the pressure transmitter within its working range as a measuring ruler, measure the original output value of the pressure transmitter to be calibrated within its working range, and calculate the zero point transition and range transition values required for the pressure transmitter to be calibrated. The calculation results are then written into the signal conditioning system inside the pressure transmitterchipRealize that the input-output curve of the pressure transmitter to be calibrated is consistent with the standard input-output curve of the pressure transmitter within its working range, and complete the calibration.