Pressure transmitter validation steps1

Pressure transmitter is a commonly used testing instruments, can will feel stress variables into standard output signal of the instrument, the main measure for gas, liquid, steam and other media. Pressure transmitter is in use process need to check, so what is the pressure transmitter calibration steps? The following project to introduce specific.

pressure transmitter calibration step

first of all, the pressure transmitter real calibration is need to use a standard pressure source input transducer. Because do not use the standard and the tuning range ( LRV、URV) Not calibration, ignore the input part ( Input pressure transmitter) To adjust the output ( Conversion transmitter circuit) Calibration is not correct.

again pressure, differential pressure detection components and AD conversion circuit, the relationship between the output current is not equal, the purpose of calibration is to find the relation of the three. Pressure source through a rubber tube connected to the homemade joint, close the balance valve, and check the seal gas path, then the ammeter ( Voltmeter) , hand device connected to the transmitter output circuit, after electrify preheating start calibration. We know that no matter what type of differential pressure transmitter, its positive and negative pressure chamber has a vent, drain valve or cock; It's for our field calibration differential pressure transmitter provides a convenient, that is to say, don't dismantle guide tube can be calibrated differential pressure transmitter. Calibration for differential pressure transmitter, the first three valve group, the positive and negative valve closed, open the balance valve, then unscrew bleed, drain valve or cocks vent, and then with homemade sub instead of positive pressure chamber exhaust, drainage valve or cock; The negative pressure chamber is keep unscrew, make it through the atmosphere.

damping adjustable to zero state, first to the zero point, and then filled with pressure adjustable full scale, make the output to 20 ma, calibration on site is fast, the zero point, fast calibration method of range. Tone has no effect on full almost zero, but the full, influential to zero in the move without the influence about range adjustment quantity of 15, namely range adjusted upward 1 ma, zero point will move up about 02 ma, and vice versa. With the conventional method for calibration of intelligent transducer is no good, because this is determined by the HART transmitter structure theory. Because smart transducer in the input pressure source and produce 4 - Between 20 ma current signal, in addition to the machinery, circuit, and microprocessor chip operation work of the input data. So calibration with conventional method. Actual calibration according to the following steps to

1 do a 4 - first 20 ma fine-tuning, the rectification of transmitter internal DA converter, because it does not involve the sensing component, without external pressure signal source.

2 do it again the fine-tuning, 4 - 20 ma, digital readout in conformity with the actual pressure signal, so you need to pressure signal source.

3 finally do reset range, 4 - by adjusting the analog output 20 ma in conformity with the additional pressure source, its role and zero (transmitter enclosure Z) , the tuning range ( R) The effect of switch is exactly the same.

more high-quality sensors at https://www. rtdcn。 Com /

key words: thermal resistance, thermocouple, thermal resistance, platinum resistance, PT100, PT1000, pressure sensor and digital temperature sensor