I bought three instruments, all of which have 485 interfaces. What do I need to do in order to connect to the DCS via 485 communication?
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They all come with a 485 interface. What needs to be done in order to connect to the DCS via 485 communication? You need to know what the conditions are, and so on
If the communication interface of the field instrument is a 9-pin serial port, and the DCS side presumably doesn’t have such an interface, then it’s necessary to add a communication card to the DCS side; you also need a communication cable. After that, you need to set the address of the instrument, followed by DCS configuration
How do I find out where the instrument’s address is? Or how to set it up
The instrument address is listed in the manual; generally, this type of instrument requires a computer connection to set the communication address.
1. All instruments are connected to the 485 bus; in other words, those two wires used for instrument communication are connected in parallel. 2. Set the baud rate of the host computer’s communication software to match that of the instruments. 3. Then, the host computer sends commands using the instruments’ addresses to request data, and that’s it.
The address of the instrument can be found on the label. If there is no label, then you are using a DogSay device. To deal with such a device, you can use addresses ranging from 001 to 255, and send commands to it one by one – you will eventually receive a response message, which will include its address number as well. :lol
Firstly, the DCS system must have the necessary interfaces, such as Modbus or support for 485 communication. If the DCS does not have these, a communication card that is compatible can be used on a computer or in a DCS card; if the DCS already supports such functions, then configuration within the DCS is required. If a card is installed on a computer, it is also necessary to consider how data will be transmitted to the DCS
By the way, I have a question: how can these three meters be connected together?
Just connect the communication wires directly together; don’t connect them in series
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