Q24: What preparations should you make before installation?
A: Before installation, you should confirm that the gas source is clean, purge the pipelines, match the connections, verify the power supply, and check the communication wiring. In addition, inspect the pressure reducing valve, filter, check valve, and shut-off valve.
Q25: How do you install the MFC?
A: We provide a signal cable with every MFC. At one end, you will find various loose wires, and each wire is numbered. To connect the cable, attach wire 9 to RS485 positive, wire 3 to RS485 negative, wire 2 to power positive, and wire 7 to power negative. In addition, the user manual contains a table that explains the meaning of each wire. You can either download the user manual from the TECHNICAL & SERVICE page, or ask our sales representative Alexa to send it to you (Alexa@biosflows.com).
Q26: Does the MFC need warm-up after power-on?
A: Yes, it does. Generally, you should warm up the MFC for 15–30 minutes; however, for high-precision or low-flow models, we recommend 30–60 minutes to achieve stable accuracy.
Q27: How do you zero the MFC?
A: First, make sure the downstream of the MFC is closed, there is no actual flow, and there is no significant pressure difference across the valve. Then, perform zero calibration according to the manual. If your model has an auto-zero function, follow the operating steps.
Q28: How do you set the flow rate?
A: You can set the flow rate through analog voltage/current, digital communication such as RS485/Modbus, host computer software, or a local knob. The setpoint corresponds to 0–100% F.S.
Q29: Why do you need a pressure reducing valve and a filter?
A: A pressure reducing valve stabilizes the inlet pressure and reduces flow fluctuations; moreover, a filter protects the internal sensor and valve orifice of the MFC, thereby extending its service life.
Q30: Can you connect the MFC directly to a gas cylinder?
A: We do not recommend connecting it directly. Because the cylinder pressure is high and fluctuates greatly, you should route the gas through a pressure-reducing valve, a filter, and a shut-off valve before connecting it to the MFC.
Q31: How do you purge the pipelines?
A: We recommend purging with N₂ or an inert gas to remove air, moisture, and particles. In addition, after using corrosive gases, you should purge the system thoroughly.
Q32: What are the power supply requirements?
A: Common power supplies include 24VDC, ±15V, or 15–24VDC, depending on the model. In addition, you should ensure low power ripple and avoid sharing lines with high-power equipment; otherwise, interference may occur.
Q33: How do you ground and shield?
A: Ground the device according to the manual. Use shielded twisted-pair wires for communication, ground the shield at one end only, and keep the cables away from power lines to reduce electromagnetic interference.
Q34: Are there environmental requirements?
A: You should avoid high temperatures, high humidity, strong vibration, strong magnetic fields, and corrosive atmospheres. In addition, keep in mind that temperature changes can affect the zero point and high-precision measurements.
Contact Us
Related Products
