Solutions to common faults in vortex flow calculation
What are the more common faults and solutions of the helical vortex flowmeter during application?
The setting of the cut-off frequency: The setting of the cut-off frequency is determined by the user based on the production changes at the measurement site to determine the starting flow of the instrument. If the cut-off frequency is set too high, the starting flow of the instrument will increase accordingly, which may cause the flow to be missed. If the cut-off frequency is set too low, the sensitivity of the instrument will increase accordingly. Some weak vibrations or stray signals from the outside may cause the instrument to start operating without the medium being measured passing through, and thus the overcounting of flow is inevitable.
2. It is relatively sensitive to interference signals such as noise or vibration. If there is a strong magnetic field near the measuring instrument or obvious noise disturbance upstream of the measuring end of the instrument, the operation of the instrument will be affected to a certain extent.
3. The wide voltage adaptability and stability issues of two-wire output: Reverse power connection, overvoltage, and surges are common problems in power supply, which should be effectively overcome. Stability is the primary consideration in instrument design, as industrial sites are often in harsh environments with extremely high requirements for reliability and stability.
Solutions
The setting problem of the cut-off frequency can be solved through the reasonable setting of the range ratio. The noise interference problem can be solved in the following two ways:
1) The installation position of the instrument should be selected as much as possible in a place without pipeline vibration or with little vibration. The vibration acceleration should not exceed 2g. If the vibration is large, vibration reduction measures should be taken.
2) The upstream and downstream bi of the sensor must have sufficient straight pipe sections. To address the wide voltage adaptability and stability issues of the two-wire output, a serial input 4 ~ 20mA current loop output circuit has been designed. After digital-to-analog conversion, it outputs in the form of 4 ~ 20mA current. It is highly suitable for the design of intelligent transmitters. 4 ~ 20mA analog communication and digital signal communication under the HART protocol can be simultaneously achieved between the main control device and the intelligent transmitter.