Author Topic: Analog Output Impedence  (Read 10577 times)

mhampson

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Analog Output Impedence
« on: July 09, 2004, 06:43:12 AM »
Hi,

I am utilizing an analog output feeding a relatively high impedence analog input on a pump controller. The analog output is dropping about .35 V (to 4.65VDC) at 100% output. I am assuming I need a higher impedence signal conditioner, which I will get.

For future reference, what is the output impedence of this circuit? From my calculations of a .35 V drop into a 65K input impedence, I get a 5K impedence. Could a supprt person verify this?

Thanks
Michael

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Re:Analog Output Impedence
« Reply #1 on: July 14, 2004, 01:06:17 AM »
The CPU supplier did not specify an exact output impedance value for the 0-5V PLC analog output. However, it is known to be of several K ohms and hence it requires that the analog device connected to it to be of 1M ohms or higher in order to avoid voltage drop at the source.
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mhampson

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Re:Analog Output Impedence
« Reply #2 on: July 14, 2004, 05:35:21 AM »
Thanks for your response, I will put a high impedance buffer in the circuit.

Michael