How to detect the feedback signal of a control valve when DCS is not activated?
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How to detect the feedback signal of a control valve when DCS is not activated?
Please be more specific – it depends on what type of signal is output by the feedback device you are using. Generally, it should be possible to measure the circuit current (if there is power supply) or the resistance of the feedback device.
I’m not sure what exactly your question means
I’m not sure what type of instrument is used for your return signal. If it’s a valve position transmitter, it can be measured using a current signal tester with a 24VDC power output; if it’s a valve position switch, then a multimeter can be used to check whether the switch is open or closed.
It supports the 4th level: that is, if the valve position feedback is in the form of a 4-20mA signal, the signal value can be measured using a thermal signal meter or multimeter; if it is a digital signal, then a multimeter can be used to check for continuity.
Typically, the valve position feedback signal is in the range of 4–20 mA. If the DCS is not activated, a multimeter or ammeter can be used to measure the feedback current, which indicates the degree to which the valve is open.
If it is 4-20ma, simply apply the signal to observe the valve’s operation
The signal must be applied first in order to measure the feedback current; otherwise, it cannot be detected
It is necessary to know whether the feedback signal for your control valve is four-wire or two-wire If it is a four-wire system, use an ammeter to measure the current in the circuit directly ； If it is a two-wire system, use a tester to measure the current in the circuit, such as VC15, VC05, and so on (domestic models).
Measure the feedback current, but the connection was broken! I’ll have to go to the site myself to check the pointer.
If measuring the feedback signal of a valve in 4-20mA format, a passive module should be used for the AI module; if the module’s input impedance is 250 ohms (which is typical), the DC voltage range can be used to measure values between 1-5V. That’s also possible.
Those supporting the 4th level mean that if the valve position feedback is in the form of a 4-20mA signal, the signal value can be measured using a thermal signal meter or multimeter; if it is a digital signal, simply use a multimeter to check for continuity