Mass flow meter wiring
Thread Content
I would appreciate it if an expert could explain the wiring aspects of mass flow meters: what is the difference between 24VDC and 220V for four-wire mass flow meters? In terms of accuracy or other aspects. 2: Are there mass flow meters with a two-wire system? What are the disadvantages or advantages compared to the four-wire system?
The wiring of mass flow meters from different manufacturers and models may vary; it is necessary to follow the wiring diagram provided for the flow meter, and no changes should be made arbitrarily.
Could you explain the wiring for a popular mainstream mass flow meter?
First of all, it should be clear that there are hardly any two-wire mass flow meters available these days (I’ve heard from colleagues that they do exist, but I’m not sure if that’s true). The power of mass flow meters, limited by their operating principle, is already well above 90 mW; it is usually around 6 W. Two-wire operation is not possible. Take the Emerson 1700 transmitter as an example. It has a set of power terminals that can accept 220AC or 24DC; the transmitter identifies this automatically. Three groups of remote transmission signals. A set of currents plus HART. A set of pulse outputs. A set of digital communication outputs includes options such as RS485 and Profibus-PA.
Pro, I’ve learned it now, haha – everything uses imported products
As a seasoned expert in mass flowmeters, I can say with certainty that two-wire mass flowmeters do exist, and they have already been brought to market； But what can be done? For common applications, not to mention two-wire systems, four-wire systems, even nine-wire systems are more than sufficient. As a product, two-wire technology is a demonstration of a brand’s strength; however, for customers, the extra cost brings no real benefit unless the price remains the same. This is a very rational discussion. As a customer, you need a mass flow meter that is two-wire, adaptive to 24/220 volts, equipped with Hart communication, has an explosion protection rating of IIC, and offers an accuracy of 0.05%. Objectively speaking, these are all features that require investment; are they really necessary for you? When choosing industrial products, the core functions are what matter most; any additional requirements are essentially a waste of resources ； Yet quite a number of manufacturers are willing to pursue high-end options. I’m really puzzled as to why E+H’s mass flowmeters don’t sell as well as Emerson’s, because in terms of cost-performance ratio, the former is much more reasonable.