Internet PLC Forum

General => Technical support => Topic started by: mhampson on July 09, 2004, 06:43:12 AM

Title: Analog Output Impedence
Post by: mhampson 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

Title: Re:Analog Output Impedence
Post by: support 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.

Title: Re:Analog Output Impedence
Post by: mhampson on July 14, 2004, 05:35:21 AM

Thanks for your response, I will put a high impedance buffer in the circuit.

Michael