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High speed measure with s7-300 and incremental counter

Created by: Orcaof at: 6/10/2014 11:30 AM (6 Replies)

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6/10/2014 11:30 AM	Rate (0)
Orcaof Posts: 7 Rating: (0)	Hi, I am currently working on a s7-300/mec and i must read the signal from channel A and B from this encoder : http://www.hengstler.de/gfx/file/shop/encoder/RI58/Datasheet_RI58-D_en.pdf After measuring them in my system, the signals are 0-4V and the rectangle impulse can be a little more faster than 1kHz but don't go much faster. I don't really need something like a specilized module for encoder, only something fast enough to not miss an impulse so my program in my plc will see them all. The currents modules i have can't follow this speed. Thank you for the future answers !
Orcaof Posts: 7 Rating: (0)
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6/10/2014 12:00 PM	Rate (2)
MicroMan Platinum Member Joined: 11/29/2011 Last visit: 12/16/2024 Posts: 1361 Rating: (232)	Hi, Set up HW interrupt on the IO card. You recieve your digit in, the rising edge interrupt your program, you place a counter into your OB4x and that is you. you do not miss any signals. You will need a DI card support HW interrupt and that is you. You can find many manuals describe the procedure. Anyway, if you need help I am happy to help. For further info about HW interrupt see: What is a hardware interrupt and how do they work in the S7-300 system? Cheers:
	Last edited by: MicroMan at: 9/11/2015 1:59:47 PM Added Link - What you read here, please check with manuals and your requirements. - Do not forget to Test, Test and Test... - If the post is helpful, please RATE it! MicroMan
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6/10/2014 2:32 PM	Rate (0)
Orcaof Posts: 7 Rating: (0)	I currently have a DI/O card, it is a 323-1bl00-0aa0 but when looking in the data i see this : Input delay • "0" to "1" transition • "1" to "0" transition 1.2 ms to 4.8 ms 1.2 ms to 4.8 ms Page 235 (http://support.automation.siemens.com/WW/llisapi.dll/csfetch/8859629/s7300_module_data_manual_en-US_en-US.pdf?func=cslib.csFetch&nodeid=10072094&forcedownload=true ) With a switching frequency max of 100Hz. If i understand this correctly then i can't use this module for my system, right ? Page 83 i found the "Digital input module SM 321; DI 16 x DC 24 V High Speed; (6ES7321-1BH10-0AA0)" which seemed fast enough but sadly now this is the voltage level in the sensor to find a "1" which don't work (13 V to 30 V when i am at 4V at "1" ) I know there is the fm350-1 counter module but i don't know if i can regulate the level of the trigger under 5V. And buying a decicated module for counter without using any of the counter options, because i only want to detect all the impulsions (i already do all the maths with channel a and b in a simulink model which will be implemented in the plc later with code generation) seems bad (but if this is the only choice i will do it)
Orcaof Posts: 7 Rating: (0)
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6/10/2014 2:41 PM	Rate (0)
TIBI68 Gold Member Joined: 12/1/2009 Last visit: 10/27/2024 Posts: 672 Rating: (147)	Dear Orcaof, we had the same problem with the signal level on a project with a 5V encoder and the FM module. If I remember correctly weinstalled something like a signal booster/converter in order to get a 24V signal for the FM. It was working perfectly. Unfortunate I don't remeber the manufacturer but I am sure you will be able to find such a device on the internet. Best Regards.
	Give us your feedback and show us your respect! We take our free time to support you with our knowledge and experience. If this post is helpfull to you kindly click on "Rate" or "Thank".
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6/10/2014 4:02 PM	Rate (0)
MicroMan Platinum Member Joined: 11/29/2011 Last visit: 12/16/2024 Posts: 1361 Rating: (232)	Hi, 1. Signals on DI modules are 0-24V. The reason of measuring intermediate signals is the fact that fast signals can not charge and discgharge the cable. You use low impedance cables or use discharge capacitors when the cable coming to the cabinet- 2. Input cards. You use any DI card have Hardware Interrupt capabilty. You can check this in the HW config under the card properties or you can use the manual. See for example this card: Digital input module SM 321; DI 16 x 24 VDC; with hardware and diagnostic interrupts (6ES7321-7BH01-0AB0 If your fast counter card nit fast enough you can go for hw interrupts. These are much faster, cheaper. For further info about HW interrupt see: What is a hardware interrupt and how do they work in the S7-300 system? Cheers
	Last edited by: MicroMan at: 9/11/2015 2:00:19 PM - What you read here, please check with manuals and your requirements. - Do not forget to Test, Test and Test... - If the post is helpful, please RATE it! MicroMan
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6/10/2014 4:38 PM	Rate (0)
Orcaof Posts: 7 Rating: (0)	MicroMan 6ES7321-7BH01-0AB0 After checking the specs it seems that it could work with my frequencies. The last problem being my voltage level, i 4V and this module go o "1" at "13 to 30 V". I found this and think this could be it : http://docs-europe.electrocomponents.com/webdocs/1073/0900766b81073c5f.pdf
Orcaof Posts: 7 Rating: (0)
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6/10/2014 5:00 PM	Rate (0)
TIBI68 Gold Member Joined: 12/1/2009 Last visit: 10/27/2024 Posts: 672 Rating: (147)	Dear Orcaof , You need to look for an amplifier. Best Regards.
	Give us your feedback and show us your respect! We take our free time to support you with our knowledge and experience. If this post is helpfull to you kindly click on "Rate" or "Thank".
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