Skip to Content

Register Login

Industry Online Support

Technical Forum

Navigation

Wrong value of temperature from rtd

Created by: ankur_gajjar at: 1/9/2015 1:01 PM (5 Replies)

Rating (2)

Thanks 1

6 Entries

1/9/2015 1:01 PM	Rate (0)
ankur_gajjar Posts: 23 Rating: (0)	Dear all, I am having S7-313C-DP PLC with me and I have interfaced 4 wire RTD with analog module having order number (331-7KF02-0AB0). Now, I have interfaced the RTD as shown in the manual and have also deactivared the unused channels and selected "Pt100 standard" in hardware configuration. Still the input value shows "-32768" (8000H) in the display at room temperature. So, what could have gone wrong? Your help will be very much appreciated. Thank you. Looking forward to your suggestions. Regards, Ankur
ankur_gajjar Posts: 23 Rating: (0)
Suggestion To thank Quote Answer

1/9/2015 1:30 PM	Rate (0)
UMENCHO Diamond Member Joined: 3/21/2006 Last visit: 9/10/2024 Posts: 10228 Rating: (1181)	What kind of RTD is connected? What values reveive betweeneach twowires when measure with multimiter (Oms)? Best regards, Hristo Mihalev

Suggestion To thank Quote Answer

1/9/2015 4:55 PM	Rate (0)
ankur_gajjar Posts: 23 Rating: (0)	Dear Hristo, The RTD is Pt100 type in 4 wire configuration and I haven't measured the resistance between the leads yet. Regards, Ankur Gajjar
ankur_gajjar Posts: 23 Rating: (0)
Suggestion To thank Quote Answer

1/9/2015 5:33 PM	Rate (1)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 9/16/2024 Posts: 12282 Rating: (2683)	Hello Ankur; What position have you set the range module for your channel group? Look on the side of the module (you must remove it from the connection rail); it should be on "A" for 4-wire RTD measurement. See the following attachment from the S7-300 Module Data manaul. Also look at the note at the bottom of the screencapture, you are getting a 7FFF(Hex) value in your measurement... S7-300 Module data manual - Siemens Hope this helps, Daniel Chartier Attachment RTD 4-wire 331-7KF02.JPG (289 Downloads)

Suggestion To thank Quote Answer

1/9/2015 5:45 PM	Rate (1)
Marcjan Platinum Expert Joined: 4/22/2010 Last visit: 5/3/2024 Posts: 5697 Rating: (715)	ankur_gajjar and I haven't measured the resistance between the leads yet. Perhaps it's time to do just that, see other thread you wrote in. /tf/WW/en/Posts/56515#top The value you get means it's not connected or configured right. Regards, Marcjan
	Problem solved? Please let us know! Please no technical questions by PM, use the forum sections for your questions.
Suggestion To thank Quote Answer

1/10/2015 12:05 PM	Rate (0)
ankur_gajjar Posts: 23 Rating: (0)	Dear Marcjan, Thanks for your help. Since I measured the resistance between two terminals, it showed the value of 166 klio ohms and I cross-checked with the inventory and they weren't sure about the RTD type as well as they don't have any product code or whatsoever. Since, the value of resistance was in kilo ohms, I assumed it as an Pt1000 RTD and interfaced it as an 4 wire current transducer and scaled it accordingly and it gives value of actual temperature with some small error. So, it seems to work fine. Once again, thanks for your help. Regards, Ankur
ankur_gajjar Posts: 23 Rating: (0)
Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users Marcjan

|

Share this page:

Share this page on...

Follow us on