Written by: Dan Weise

Recently, I was helping a customer troubleshoot the analog input on his Siemens MultiRanger 200.

For common troubleshooting, using voltage values to confirm a zero, mid point and span is all that’s needed.  I find it easier to put a voltmeter across the analog input and read the voltage drop than to wire an amp meter into the circuit to read directly, but that assumes that the analog input’s resistor value is a known. For the most commonly used input resistance (250 ohms), the equivalent voltage drop is 1.0 to 5.0V.

Being the guy who actually reads the user manuals, I looked in the Siemens manual to find the input resistance, and it’s not there.

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