How to enable communication between a scale with an RS232C interface and a PC using VB
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1. The distance is relatively large, so routing is necessary; one PC can be used to control multiple scales, and it’s best to use VB for this purpose. 2. It is necessary to read data as well as control the scales (the scales are equipped with PLC controllers). 3. The weight values received need to be sent to a printer (the printer is located at a distance from the computer; how can it be connected via an Ethernet cable?) ? ? ) Which senior knows this? Please guide me, thanks!
1. RS232C can only perform point-to-point communication over short distances, so it must be converted. To achieve conversion, in addition to its point-to-multipoint communication capability, RS485 communication uses a comparison-based signaling method; data transmission requires a line voltage of more than 200 mV, which enables long-distance transmission with a maximum distance of up to 1,200 meters. Repeaters can also be used for extension. So, if you have multiple scales, RS485 communication should be used. Additionally, it’s necessary to determine what protocol your PLC uses – whether it’s MODBUS or PROFIBUS, or some other communication method specific to the PLC manufacturer – before anything can be designed. As for the issue of the printer being far away from the computer, it’s very simple: just install a printer on the machine where you run the VB program. If an Ethernet cable is used, and the distance is large, the cost of using an optical fiber cable will be higher than the cost of buying a printer.
It was explained in more detail upstairs. One more thing: printers with a USB interface work well; distances of over ten meters aren’t a problem. For longer distances, use a local area network; just buy a LAN printer sharing device.