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Unread 09-04-2014, 13:25
TheHolyHades1 TheHolyHades1 is offline
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Wiring a pressure transducer

Hello.

I recently discovered that we have a pressure transducer from the 2004 kop lying around, completely unused. I was able to find the spec sheet for the transducer here: http://team358.org/files/pneumatic/5...sureSensor.pdf

I believe I am to connect this via pwm to the analog breakout; however, I found that the ports on the breakout supply 5v at .25 amps, whereas the transducer is rated for 8 mA at best. Do I need to add a resistor in parallel from the power to reduce current, or am I missing something obvious here?
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Unread 09-04-2014, 13:36
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Re: Wiring a pressure transducer

That's the max current draw for the analog breakout. If the sensor needs less current then that at 5 volts you should okay.
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Unread 09-04-2014, 13:58
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Re: Wiring a pressure transducer

.25 amps is 250 milliamps. 8 milliamps will not be a problem.
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Unread 09-04-2014, 14:05
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Re: Wiring a pressure transducer

I'm guessing this means that the breakout will only supply as much current as the device needs, not a set current?
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Unread 09-04-2014, 14:18
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Re: Wiring a pressure transducer

Correct. We regulate voltage, not current.
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Unread 16-04-2014, 15:18
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Re: Wiring a pressure transducer

Things that supply current only have a maximum that can be drawn.
To make an analogy to mechanical forces, voltage is like how fast a shaft spins, and amperage is like the torque.

The motor spinning it has a maximum torque, though this might not all be used. (And a load causes a speed drop... unless there is a control loop going on.) A power supply has a maximum output amperage, though that might not be all that is used. (And a load causes a voltage drop... though since the breakout is regulated, it'd be hard to experience this.)
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