Weighing sensor brands and issues related to sensor calculation and accuracy
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Hello everyone, may I ask: 1. Which imported and domestic brands of load cells have better quality? 2. How to calculate the actual weight when four load cells are connected directly to the PLC (with four load cells placed at the four corners of the hopper, along with mechanical overload protection devices)? 3. Which is more accurate: having four load cells connected directly to the PLC for calculation, or having those same four load cells connected directly to the wiring box provided by the manufacturer, with the wiring box generating a 4-20Ma signal? What precision can be achieved?
Weighing sensors are generally made by the German company HBM; the signals from these sensors are sent to the weighing controller (UNIPULSE F701C). The controller then outputs digital signals to the PLC, which is used to control actions such as the feeding rate of the cylinders, stopping the feeding process, and releasing material from the hopper. Four sensors are connected in parallel to the controller
Mettler Toledo! Sartorius!
The wiring box of the load cell is used to adjust the angle difference; it does not output a 4-20 milliampere signal. The wiring box can be used or not – domestic load cells are quite good these days as well
Everything I’ve encountered doesn’t have sensor signals going directly into the DCS; instead, they are converted to a 4-20 mA signal through an on-site control box before being fed into the DCS. The accuracy is fairly good, but it’s important to pay attention during installation, as well as to ensure that there are no interference sources in the surrounding area.
There is no signal from a weight sensor that goes directly to the PLC or DCS. They are all complete sets of equipment supplied by weighing manufacturers (which can be referred to as controllers), and it is these controllers that output milliampere or voltage signals.
Brands Schenck, Toledo. It’s absolutely premium. The domestic Hangzhou China Resources version is also good. As the previous speakers have also made it clear, I’ve never seen sensors that are connected to the system alone; they usually come as sets along with transmitters.
1. Foreign brands: HBM, Toledo, Sartorius, Fulintek; Domestic brands: Keli, AVIC. 2. The sensors output signals in mV format; a transmitter or instrument is required to convert these signals into analog or digital forms before they can be connected to a PLC