How?

Hi

I've come across a 0-10v analogue input into a 4-20mA analog input card... and the system appears, well is working.

The plc is a Siemens S5 115. The card is a "half card" 6ES5-463* which only shows it as current loop configurable.

A change in the input results in a PIW value change when monitored.

How can this be?
What's the drawbacks?

Thanks in advance
s.f

Many current input analog cards have a precision resistance for the input. The current thus translates to a precision voltage change which is the actual quantity measured by the card. You might observe if the reading maxes out at about 5 volts. Many current input cards use a 250 ohm resistor resulting in a 1-5 volt DC signal.

This is typically done in cases where you're using an analog input on something, let's say a paperless recorder, to monitor a signal in a 4/20ma control loop.

If that recorder were to fail, necessitating replacement and/or unplugging the wiring harness, you may not want to (or be able to) break the control loop. Using a fixed resistor down on terminal strip someplace to provide a 1/5v signal then becomes a good solution--

silva.foxx said:

Hi

I've come across a 0-10v analogue input into a 4-20mA analog input card... and the system appears, well is working.

The plc is a Siemens S5 115. The card is a "half card" 6ES5-463* which only shows it as current loop configurable.

How can this be?

s.f

Click to expand...

The rest of the code on the card, where you gave us the * , tells what the card really see's, below are 5 options I Googled.

Siemens6ES5-461-8ME11ANALOG INPUT MODULE QTY 4 4-20MA
Siemens6ES5-463-4UA12INPUT MODULE ANALOG +-10V+-20MA C/S.GAL 8PT
Siemens6ES5-463-4UA13INPUT MODULE 4 POINT S5 463 1/10V/2
Siemens6ES5-464-8MA11INPUT MODULE ANALOG 4POINT +50MV
Siemens6ES5-464-8MA21ANALOG INPUT MODULE 4 POINT 50MV LINEARIZING

Siemens 6ES5-463-4UA12 INPUT MODULE ANALOG +-10V+-20MA C/S.GAL 8PT

I tried the Siemens support site after info on this card but to no avail.

Enough said Gil47 in your list. Just a little cautious when I saw the card with only current loop settings on the case. Obviously no literature to hand.

Thanks all.