Wired connections and analog channels
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After some analytical instruments in my system generate electrical signals, these signals are sent to the QMR via hard wiring, while other analytical instruments have a single-channel analog output that is sent to the QMR. As I understand it, hardwiring refers to a single wire (I’m not sure if that’s correct); what does single-channel analog output mean?
A hardwired connection to the QMR refers to a control or measurement circuit formed by direct cable connections. Single-channel analog output: it refers to an output of 4–20 mA (or 1–5 V) with one circuit.
Today I found the original text: “Gas chromatography has separate hardware for generating 4–20mA signals, which are then connected to the QMR via hard wiring.”； The oxygen analyzer features a single-channel analog output and a closed-contact fault signal sent to the QMR ； ”. Since all signals sent to QMR are 4–20mA signals, isn’t the single-channel analog output transmitted via a cable?
Does the term \"wired connection\" referred to here mean communication methods such as Modbus? Is it still a digital signal?
For digital signals, the values shouldn’t be displayed continuously, right?
The translation might be incorrect; I’ve seen it before. The 4–20mA signal of gas chromatography may be HART-enabled.
It’s also possible that there’s a translation error. So, what is the HART protocol?
You can look up the HART protocol online; it’s recommended that you search for information on its conceptual aspects on your own. Otherwise, the questions would go on endlessly, haha.
Without looking at the original text, it’s difficult to analyze this; here, is the hardwiring connected in a signal-based manner (including analog signals), and does a single channel represent a connection method with communication capabilities? Let’s discuss this! !
I understand that the two are the same; a single-channel setup also requires a wired connection in order to output to another device.
Yes, my understanding is the same as the person above – whether it’s a single-channel system or not, the signal must be sent to the DCS via hard wiring.