Skip to Content

Register Login

Industry Online Support

Technical Forum

Navigation

Overflow problem in AI module(6ES7 331-1KF01-0AB0)

Created by: Kadhar at: 7/15/2009 5:59 AM (4 Replies)

Rating (0)

Thanks 1

5 Entries

7/15/2009 5:59 AM	Rate (0)
Kadhar Posts: 16 Rating: (0)	Dear all, we are using the above mentioned AI module and we are trying to receive KW value from a transducer(please note transducer ouput range is 4-20mA). So we assigned in hardware configuration, 4-20mA.we connected transducer output in one of the channel in AI module and measured current and got 21.26mA and it gives overflow error.So suggest on this problem.noted down we changed another spare channel also.still problem persist.
Kadhar Posts: 16 Rating: (0)
Suggestion To thank Quote Answer

7/15/2009 7:06 AM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 10/11/2024 Posts: 12287 Rating: (2685)	Hello Kadhar; Fisrt thoughts: How did you connect your channel, and what type of sensor have you connected? You could have 2-wire (powered from the Analog module) or 4-wire transducer (powered from its own power supply). If you connected a 4-wire as a 2-wire unit, you will expect to have an overflow (double the input current...). Also, make sure all you M- pins are shorted anmd connected to earth, this limits measuring errors due to cross-channel interference See the attached dioagram, extracted from the S7-300 Module data manual; It shows typicalwiring diagrams for 2- and 4-wire transducers on your analogmodule. http://support.automation.siemens.com/WW/view/en/8859629 Hope this helps, Daniel Chartier Attachment S7-331-1KF01_Current.JPG (563 Downloads)

Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users Ayman Elotaify

7/16/2009 4:18 PM	Rate (0)
Ayman Elotaify Platinum Expert Joined: 5/28/2008 Last visit: 10/7/2024 Posts: 4515 Rating: (839)	dchartier If you connected a 4-wire as a 2-wire unit, you will expect to have an overflow (double the input current...). Daniel Chartier I am completely agree with Daniel Chartier. I want only to clarify some thing here. Why in the above mentioned case the AI channel recieves double of the value? Thus because when you connect the 4-wire transducer like 2-wire connection, you will have something like two current sources. one is driven from the transiducer and the second is driven from the module it self. Regards,
	Last edited by: Ayman Elotaify at: 7/16/2009 4:20 PM Last edited by: Ayman Elotaify at: 7/16/2009 4:19 PM Ayman Elotaify
Suggestion To thank Quote Answer

7/18/2009 3:03 PM	Rate (0)
H-H Platinum Member Joined: 7/2/2008 Last visit: 9/30/2024 Posts: 928 Rating: (308)	Dear Daniel Chartier, Dear Ayman Elotaify, Giving you all respect and expertise but I couldn't figure out how double current would flow in the circuit. I hope you can illustrate it little bit more. I don't know howconnecting 4-wire transducers as 2 wire transducers according to wiring diagram of 1KF01 module will double the current. I'll assume that measured physical valueshouldgive8 mA, and the 4-wire transmitter will try to force that 8mA in a certain direction then how would that 8 mA be doubled to 16 mA? Pleasecomment onthe attached file. Then, It seems to me that Mr. Ayman has mixed up between the case we have (1KF01) and other active modules (7KF02 for example). Ayman Elotaify Thus because when you connect the 4-wire transducer like 2-wire connection, you will have something like two current sources. one is driven from the transiducer and the second is driven from the module it self. Regards, Actually the channel/moduleshouldn't act as a current source even if it is an active channel (with potential across its terminals). It just applies potential across the terminals but the current is varied by transmitterand is totally depending onmeasured physical value. One more important thing is thatthe 1KF01 will always act as a passive module. Back to the main problem, Sometimes, transducers/transmitters are configured to give 21mA when they have internal error or extreme overload. So, at PLC side, when it receives this 21mA, it will mean something is wrongwith transmitter. Best regards. H-H Attachment 4 wire VS 2 wire.pdf (490 Downloads)
	Last edited by: H-H at: 7/19/2009 12:04 PM Edit : I deleted some words and put them again. Sorry for inconvenience Last edited by: H-H at: 7/19/2009 11:43 AM
Suggestion To thank Quote Answer

7/21/2009 12:25 PM	Rate (0)
Aristotelis Posts: 147 Rating: (34)	Kadhar measured current and got 21.26mA and it gives overflow error. H-H Sometimes, transducers/transmitters are configured to give 21mA when they have internal error or extreme overload. So, at PLC side, when it receives this 21mA, it will mean something is wrongwith transmitter. Hello Kadhar Are you able to put a current meter in order to measure the actual current that your transducer is transmitting? Essentially, can we be sure if the problem is on the transmitter (i.e. it gives more than you are expecting) or on the AI module (it misinterprets the current value) ? If we can measure the current, and be certain that is less than 20 mA and you still get an overflow error, than it seems to me that the problem is on the AI module. Otherwise, the problem lies on the transmitter, and more info may be required to better understand your problem (specifications, manual, etc.) Aristotelis
Aristotelis Posts: 147 Rating: (34)
Suggestion To thank Quote Answer

|

Share this page:

Share this page on...

Follow us on