Contents
How to troubleshoot unexpected output from a sensor?
Incorrect or unexpected output from the device under test or sensor – Use an oscilloscope to check the output of your device under test or sensor to see if the unexpected behavior is caused by the NI device or the third party hardware. Also test your oscilloscope to make sure it is functioning properly by testing other known signals.
Where does the analog input for PLC come from?
Analog inputs can come from a variety of sensors and transmitters or both. For example one one the thermocouple types connected to a transmitter, which is then connected to a PLC analog input.
What causes offsets and errors in analog measurements?
Ground loops can cause offsets and error in measurements. For information on troubleshooting grounding issues see the Field Wiring and Noise Considerations for Analog Signals article. Specifically, section two on Measuring Grounded Signal Sources and section three on Measuring Floating (Nonreferenced) Sources.
How to troubleshoot unexpected analog measurement setups?
Specifically, section four Minimizing Noise Coupling in the Interconnects, section six Solving Noise Problems in Measurement Setups, and section seven Signal Processing Techniques for Noise Reduction.
What causes a low O2 sensor voltage signal?
Excess oxygen in the form of regular ambient air will send the O2 sensor voltage signal low (under 0.450 volts) and lack of it will send the voltage signal high (over 0.450 volts). A stuck open EGR valve will create a lack of oxygen in the exhaust, since the re-circulating exhaust has all its oxygen already burnt .
What causes unexpected voltage measurements to go away?
If you are experiencing an unexpected voltage in your digital channel measurement or your unexpected measurements go away when you are only sampling from one channel, this may be due to ghosting between signals. Ghosting can be caused when using a high sample rate on multiplexed devices.
Which is more damaging a voltage surge or a power surge?
As a result while both phenomena can be disruptive in a system and cause considerable damage, generally speaking voltage surges are considered more damaging. This is due to the longer period of time in which the electric circuit must deal with the excessive power.