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pre-alarm

Created by: Bonsai72 at: 7/2/2008 9:00 AM (4 Replies)

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7/2/2008 9:00 AM	Rate (0)
Bonsai72 Advanced Member Joined: 2/12/2008 Last visit: 8/2/2024 Posts: 70 Rating: (0)	Hi all I'm using a CPU D435 with Sinamics drive. The machine is composed by 4 axis in positioning mode. I need signal on a Panel with a message when the current reach a value (e.g. 70% of the maximum current). At the moment for this purpose I read the current with function readdriveparameter and I compare this value with a threshold, but this function is slow (it need more than 10ms per axis). Is there a method is Sinamics to have an output when the current reach a certanin value? (Sorry but I don't know very well Sinamics because I used Simodrive right now). Thankyou

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7/3/2008 12:41 AM	Rate (0)
Jerry Posts: 116 Rating: (7)	Hi, there are 2 data transfer mechanism: - non cyclic data transfer (e.g. readdriveparameter) - cyclic data transfer. The non cyclic data transfer is slower, because data transfer depends on communication load. (good for high data transfer, but notvery wellfor fast response times) Better is to use the cyclic interface, because you have a data transfer each DP cycle. Use a telegram extension and put the parameter on the telegram. Bye Jerry
Jerry Posts: 116 Rating: (7)
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7/4/2008 9:02 AM	Rate (0)
Bonsai72 Advanced Member Joined: 2/12/2008 Last visit: 8/2/2024 Posts: 70 Rating: (0)	Thankyou Jerry I've extended the telegram with the parameter p78 (actual current). The problem is that the value p78 receivedfrom CPU is not the directvalue, but is a DWORD value wich is a proportion ofthe maximum value (par.2002). To find the exact value I used this formulaCurrent = p2002 *p78 / 1191462666.0. I evaluated the value of the costant 1191462666.0 reading the correct value of the currentby the oscilloscope. Probably this value it is not accurate, butI don't know the exact value. Were can I find the exact formula of conversion? Why everything mast be so hard ? Thankyou

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7/4/2008 4:27 PM	Rate (1)
ThomasD Posts: 39 Rating: (9)	Hello Bonsai72 The factor is 1073741824 (à 4000 0000 hex). Physical word and double word values are inserted in the telegram as referenced variables. p200x are relevant as reference values (telegram contents = 4000 hex or 4000 0000 hex for double words if the input variable has a value of p200x). The formula is: Current = p2002 * received value / 1073741824 Please have a look to the following document page 350. http://support.automation.siemens.com/WW/view/en/26545136 Regards ThomasD
ThomasD Posts: 39 Rating: (9)
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7/11/2008 1:31 PM	Rate (0)
Bonsai72 Advanced Member Joined: 2/12/2008 Last visit: 8/2/2024 Posts: 70 Rating: (0)	Tankyou ThomasD now everything is OK.

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