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Encoder to Digital input

Created by: alindsay81 at: 3/6/2008 2:37 PM (6 Replies)

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3/6/2008 2:37 PM	Rate (0)
alindsay81 Posts: 38 Rating: (0)	Hello all, can anyone tell me if its possible to wire this encoder to a digital input? how would i go about it? What speed is a standard digital input card good for ? Encoder is 64 pulse/rev @ 40rpm I want to count pulse's in order to work out distance. Attachment AS_SENSOR-BEARING_SKF.pdf (388 Downloads)
alindsay81 Posts: 38 Rating: (0)
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3/7/2008 9:18 PM	Rate (0)
Denilson Pegaia Platinum Member Joined: 9/23/2005 Last visit: 11/11/2024 Posts: 4351 Rating: (1452)	Hi, a semiperiod of your application is: 60 / 64 / 40 / 2 *1000 = ~11ms Generaly the IO has a input delay of 4.7 ms. There is modules with shorter delay time (at microseconds). See St70, chapter 4 (www.siemens.com/simatic/printmaterial). If your program runsfaster as 11ms,itis ok.
	Denilson Pegaia Siemens Industry Sector Technical Support
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3/8/2008 8:17 PM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 9/26/2024 Posts: 703 Rating: (96)	Hello, I would recommend to use counter module, for example FM350-2 or another type, depends of your application... Checkthis information: http://support.automation.siemens.com/WW/view/en/2742764 And install package here: http://support.automation.siemens.com/WW/view/en/28554065

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4/1/2008 9:38 AM	Rate (0)
manmeet Gold Member Joined: 1/3/2006 Last visit: 2/19/2024 Posts: 726 Rating: (71)	Hi there Pegaia You said: a semiperiod of your application is: 60 / 64 / 40 / 2 *1000 = ~11ms Now you are deviding it by 2, because a pulse consist of rising and falling edge both. Right?? That is a pulse consist of both ON and OFF period. And 11ms is ON periodas well asOFF period, so a pulse is of ~22ms right?? We need to take into account 11ms and not 22ms because its ON part of the pulse which plays the part, right??? Just need conformation to remove the doubts Manmeet

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4/1/2008 9:58 AM	Rate (0)
alindsay81 Posts: 38 Rating: (0)	I have wired the encoder output to a digital input and supplied the encoder with 24vdc from the same power supply. I dont seem to be getting a 24vdc pulse back from the encoder. Is it as simple as 24vdc supply and signal back to input card or do i need to do something else ?
alindsay81 Posts: 38 Rating: (0)
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4/1/2008 11:35 AM	Rate (0)
ramiv Posts: 55 Rating: (1)	Did you look the pdf you provided?. It seems that it is an open collector output, connect 1470ohm resistors from +24v into sensor outputs as in the drawing. Also take into consideration that if the conveyor stops into a particular 'spot' and there is some kind of vibration at the machine you may get additional pulses, and the position is not accurate and the error will accumulate. You should take both A and B inputs, and they both must chance state in order to incerement the position. We even made an external TTL-logic card for this, it evaluates the A/B pulses and gives only one incemental pulse output, thus we needed only direction 'forward'.
ramiv Posts: 55 Rating: (1)	Last edited by: ramiv at: 4/1/2008 11:37 AM
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4/1/2008 12:08 PM	Rate (0)
alindsay81 Posts: 38 Rating: (0)	Thankyou, I have ordered said resistors from RS and will give it a try tomorrow when they arrive. Also thanks for your advice on vibration etc i will keep this in mind if i run into problems later
alindsay81 Posts: 38 Rating: (0)
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