How is a 250-ohm resistor usually added?
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How is a 250-ohm resistor usually added? A 250 ohm resistor is connected to the positive terminal in the junction box – I don’t understand what that means How to add it?
Generally, a 250-ohm load resistor should be connected when taking over the controller; it can be connected to either the positive or negative terminal.
Connect a 250-ohm load resistor in series in the circuit.
Adding a 250 ohm resistor is generally done to obtain a 1-5V signal
Convert the 4-20mA current signal into a 1-5V voltage signal, with a 250 ohm resistor connected in series in the circuit； To ensure reliable communication between the operator panel and the smart instrument, there should be a resistance of at least 250 ohms between the operator panel and the power supply.
As long as the transmitter has sufficient load capacity, series connection is possible
There are generally two situations in which a 250-ohm resistor is required: first, to convert a 4-20 mA signal into a 1-5 V signal, it is necessary to connect the resistor in parallel with the signal terminal. II: To enable online verification and debugging of the handheld controller, resistors are connected in series in the measurement circuit
A 250-ohm resistor is connected in series to enhance the load capacity and improve communication; however, communication is still possible sometimes without it
Thank you, big bro. I also want to ask, should the resistor be connected between the positive and negative terminals of the power supply? That’s equivalent to being connected in series in the circuit, right.....
It enables the conversion of current to voltage signals: when the supply voltage remains at 24V and the instrument outputs 4–20mA, adding a 250 ohm resistor allows the corresponding voltage signal to be detected!
Is it to connect the two ends of the resistor to 24V+ and the positive pole of the field signal line? Or
Reply to floor 11: It should involve removing one wire from the instrument that uses a two-wire wiring method on-site, connecting the removed wire to one end of a resistor, and connecting the other end of the resistor to the terminal on the instrument corresponding to the wire that was removed. It doesn’t matter which wire is removed. The same procedure can be followed in the control room, with the same result.
When to add a 250-ohm resistor depends on the specific situation. The DCS itself represents a large load, so there is no need to add such a resistor. In a laboratory setting, sometimes the load imposed by the DC24V power supply is not sufficient; in that case, it is necessary to connect a 250-ohm resistor between the HT handheld controller and the power supply.
My understanding is that the digital signal generated according to the HART communication protocol is superimposed on the transmitter’s 4–20mA analog current signal. To achieve this goal, a resistor of around 250 ohms needs to be connected in series in this circuit. The HART communicator is connected to both ends of this resistor, allowing relevant signals to be modulated into or demodulated from it, thereby enabling communication between the HART communicator and the transmitter. In that case, it should have nothing to do with the internal resistance of the transmitter or the value of the internal resistance in the DCS-related cards.
The resistor is connected in series in the control circuit, with no distinction between positive and negative.
A 250-ohm resistor is connected in parallel; this is how I make the connections on the 375 controller
Connecting a 250-ohm resistor in series in the circuit essentially converts a 4–20mA signal into a 1–5V voltage signal – is this understanding correct? Please give more guidance~~~
The resistor is connected in series in the control circuit, and it has no positive or negative polarity. Those upstairs, don’t get it wrong. As for the resistance value to be used in series, around 200 ohms will suffice; it is sufficient to ensure that the transmitter’s voltage range is maintained.
If the input signal to the receiving instrument is a 1-5V voltage signal, then a 250-ohm precision resistor is required to convert the 4-20mA signal into a voltage signal.
The 375 handheld device indicates that a 250-ohm resistor should be connected in series, but in my actual use, neither the EJA nor the ROUSMENT devices required such a resistor, and communication worked normally. Is it really necessary to connect a resistor in series?