PT1000 sensor on a LOGO! 12/24RCE

Kimmerrild · Jul 13, 2012

I'm no genie on PLC's.
I'm elektrician of craft, so I have the basics of it. anyhow.

I have bought myself a LOGO! 12/24RCE witch I wanna connekt 4 sensors of PT1000.

How is it that I wireconnekt the sensor to the PLC?
It's a 2wire cable that runs to the sensor. it regulates on 0-10V correkt?
I have some 6,6kohm resistors, but nomatter how I try to connekt the stuff together, it dosent seems to work when i go in "online test" with the LOGO. it either say 1000 or 0 in the "internal value"

Sooo.
How do I figure this out, anyone?
Thanks in adv.
Kim.

Jeff23spl · Jul 13, 2012

what do you mean by pt1000? is it RTD PT100 sensors ? if yes, you need an RTD input card like a LOGO AM2 PT100

The built in analog input are rated o-10v and to use it with an RTD probe, you would need an RTD transmitter converting the ohms signal to 0-10v signal.

I'm not familiar with logo programming but first we need to figure out what is the sensor signal range...

Kimmerrild · Jul 13, 2012

I thourt that the PT1000 sensors could go directly in on the PLC.
Yes. the input on the PLC is rated 0-10V.

I cant use a PT1000 sensor on the LOGO AM2 PT100 module?, correkt? it can only handle PT100'rds?

So inorder to make this setup to work, I would need what?
Currently i have
4*PT1000 sensors
1*LOGO! 12/24RCE
1*LOGO! DM8 12/24R

Since I'm using the setup for a solarheating array, i would like to use the 1000'rds due to the higer resolution.

danw · Jul 13, 2012

PT's are platinum resistance sensors. They do not generate a voltage. Their resistance changes with temperature. Typically the analog circuit generates a constant current and reads the voltage generated by IR drop across the resistance.

The sensor output must match the PLC input.

There are devices called temperature transmitters that convert from resistance to current/voltage, but they're not cheap.

Kimmerrild · Jul 14, 2012

Correkt. a transmitter is needed

You'r correkt.
A transmitter trat converts the Ohm around to 0-10 voltage.
I thourt that it automatic would do that if you applied a +24VDC voltage to the one side of the sensor, and the other end into the input.

No can do. I e-mailed a buddy of mine that works around the world atm, and he confirmed my worst fear. I need to spend more money on the projekt, becos you'r right again - they aint cheap!

Thanks for the advices.

I'll go with the AM2 PT100/PT1000 module

shooter · Jul 16, 2012

Yesa converter is needed, if low price then look for a XTR102 (you can make yourself (the output is 4/20 mA but with one simple resistor is possible to go to 10 volts.
(have a 2 outputrelais switch between your channels.

Jeff23spl · Jul 16, 2012

Kimmerrild said:
You'r correkt.
A transmitter trat converts the Ohm around to 0-10 voltage.
I thourt that it automatic would do that if you applied a +24VDC voltage to the one side of the sensor, and the other end into the input.

No can do. I e-mailed a buddy of mine that works around the world atm, and he confirmed my worst fear. I need to spend more money on the projekt, becos you'r right again - they aint cheap!

Thanks for the advices.

I'll go with the AM2 PT100/PT1000 module

RTD resistance change is so small and not completly linear so you can't do it this way. This would work for a potentiometer but not for an rtd probe...

so the right logo card is the best option as you would need just a 4 input card instead of 4 individual transmitters....

I'M just surprised that the person where you bough the logo and stuff didn't helped you to buy the right card for your RTD...

the_47 · Jul 6, 2013

NoFirst of all. It is posible to make it work without any aditional modules. Siemens logo počni version OBA 06, have four analog input that respond in scale 0-10V, but we have 24V (DC ofcourse) and we need to scale it down to 2V. It's simple mate. Secondly we need to close sercuit by conecting one end of pt1000 to 0V And second end to 308ohm resistor, then from second end of resistor to 2V and from 2V to analog input. That is conecting part . Then it's time for PROGRAM. My english is not to good, but point is that is posible to connect pt1000.

el greco · Jul 6, 2013

may be for your application you need this http://www.lkmelectronic.de/ShopXS/...g_MessumformerSonderbauformen_Ausgang010V.htm you can read real values with this.

balash · Jul 7, 2013

Jeff23spl said:
I'M just surprised that the person where you bough the logo and stuff didn't helped you to buy the right card for your RTD...

you would be amazed on what one can ran on to...
i worked on a project where designer chose PT100 for RTD and PLC card with output for thermocouples, and sales person sold him a card with analog 4-20mA output...

i could write for more

but that was by far the "funniest"

PT1000 sensor on a LOGO! 12/24RCE

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