Hi everybody,
My question isn't directly PLC related this time, but I have a feeling some of you could answer it anyway
I have an board up here that takes in a passive, 0 to 90 ohm input from a fuel level sensor, and converts it to a 0-100% fuel level. The customer wants to switch to a more accurate fuel level sensor, which can output either 0 to 10 V or 4-20 mA. Is there a simple circuit we could add that would trick the board into thinking it is getting a 0 to 90 ohm input from a 0 to 10 V or 4-20 mA source?
Also: when the passive resistance input ranges from 0 - 90 ohms, the input is acting as a constant current source, with current constant at 2.5 mA through the resistor, and the voltage is varying between 0 and 225 mV. If it goes higher than about 150 ohms it shuts off with a broken fuel sensor alarm. Tomorrow my manager wants to try just hooking up a 0 - 225 mV source up to it and slowly increasing it, but I have a feeling the constant current source won't like being in parallel with our constant voltage source one bit. Any suggestions?
My question isn't directly PLC related this time, but I have a feeling some of you could answer it anyway
I have an board up here that takes in a passive, 0 to 90 ohm input from a fuel level sensor, and converts it to a 0-100% fuel level. The customer wants to switch to a more accurate fuel level sensor, which can output either 0 to 10 V or 4-20 mA. Is there a simple circuit we could add that would trick the board into thinking it is getting a 0 to 90 ohm input from a 0 to 10 V or 4-20 mA source?
Also: when the passive resistance input ranges from 0 - 90 ohms, the input is acting as a constant current source, with current constant at 2.5 mA through the resistor, and the voltage is varying between 0 and 225 mV. If it goes higher than about 150 ohms it shuts off with a broken fuel sensor alarm. Tomorrow my manager wants to try just hooking up a 0 - 225 mV source up to it and slowly increasing it, but I have a feeling the constant current source won't like being in parallel with our constant voltage source one bit. Any suggestions?