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High Speed counter app.

Created by: jac22 at: 9/20/2010 2:06 PM (8 Replies)

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9/20/2010 2:06 PM	Rate (0)
jac22 Posts: 3 Rating: (0)	I have an application that I want to measure the counts from two motor encoders both giving 1024 ppr @ 1750rpm. A common prox is used to gate the counters but I need to know in the program that the stored values are from the same event when the code is evaluated. The FM350-2 looks to be the card but can’t count fast enough and the FM350-1 is only one channel. Is there a way of using the FM350-1 say with a timestamp? Any ideas would be appreciated. thanks
jac22 Posts: 3 Rating: (0)
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9/21/2010 11:32 AM	Rate (0)
miami Platinum Expert Joined: 8/31/2005 Last visit: 8/20/2024 Posts: 2198 Rating: (328)	Have a look on the this modules: 1Count 24V/100KHZ 6ES7 138-4DA04-0AB0 1Count 5V/500KHZ 6ES7 138-4DE02-0AB0 When you use them with a isochrone PROFIBUS, you should (I'm not shure!) get synchronized values.

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9/23/2010 6:37 PM	Rate (0)
gre_m Posts: 947 Rating: (45)	FM350-2 work up 10 or 20KHz. 1750rpm< 300rps. how many pulses have to turn the sensor?
gre_m Posts: 947 Rating: (45)
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9/24/2010 9:41 AM	Rate (0)
miami Platinum Expert Joined: 8/31/2005 Last visit: 8/20/2024 Posts: 2198 Rating: (328)	jac22 1024 ppr @ 1750rpm 1024 p/r * 1750r / 60s = 29867 p/s ----> 30 kHz

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9/24/2010 6:58 PM	Rate (0)
gre_m Posts: 947 Rating: (45)	I not understand "ppr". This is a pulse per round? 1Count 5V/500KHZ - need 2 way (4 wire) for pulse. 1Count 24V/100KHZ -1way (2wire)or 2 way (4 wire)for pulse
gre_m Posts: 947 Rating: (45)	Last edited by: gre_m at: 9/24/2010 7:03 PM
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9/26/2010 9:38 AM	Rate (0)
UMENCHO Diamond Member Joined: 3/21/2006 Last visit: 9/10/2024 Posts: 10228 Rating: (1181)	gre_m I not understand "ppr". This is a pulse per round? Yes. About connection look at http://support.automation.siemens.com/WW/view/en/9264111 Best regards, Hristo Mihalev

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9/27/2010 11:04 AM	Rate (0)
miami Platinum Expert Joined: 8/31/2005 Last visit: 8/20/2024 Posts: 2198 Rating: (328)	gre_m I not understand "ppr". This is a pulse per round? It's "pulses per round" or "pulsesper rotation"
	Last edited by: miami at: 9/27/2010 3:45 PM
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9/27/2010 3:33 PM	Rate (0)
jac22 Posts: 3 Rating: (0)	Thanks for the suggestions but the exsisting system currently employs two FM350-1’s so I must go with them. Plus I like the speed of having them on the same backplane as the CPU. From what I understand there is a bit in the DB of CNT_CTL1 that indicates a “New latch value”. So I can use that bit for the card to confirm that latched values are from the same event. -Yes ppr = “pules per revolution” is a parameter when ordering an encoder. Cheers
jac22 Posts: 3 Rating: (0)
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9/28/2010 11:44 AM	Rate (0)
jacek d Platinum Member Joined: 9/23/2005 Last visit: 9/13/2024 Posts: 4697 Rating: (721)	If your plc scan time is twicefaster then the gating signal (this common prox) then it's enough to check the status of the gate on each counter and when both are closed you can be sure that both counts are from same event (+/- 1 us ).
	Regards, Jacek What is confusing you is the fact that you never see a number but always its digit representation. So you end up thinking that the number is the representation. - Andrej Bauer Any claims against me - based on whatever legal reason - resulting from the use of any code and/or ideas presented on this forum shall be excluded. #StayWithUkraine
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