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S7300 - make "archive" in db block

Created by: F1Kimi at: 12/13/2011 12:40 PM (6 Replies)

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12/13/2011 12:40 PM	Rate (0)
F1Kimi Posts: 3 Rating: (0)	Pease help... I have a problem, I'm not a great programmer so help me. I have to make an archive in DB blockwith recorded date, time andadequate bit. so, in my processIhave a situation (example:warning -M20.0 goes from 0 to 1) and in this moment I have to record state of anotherbit (example M20.1;0 - bad piece, 1 - good piece). how to transfer this datas in DB block (date:time:bit)? how many datas I can save (CPU313 - 6ES7 313-5BF03-0AB0)? can I expand a memory? how canI download this datas from DB to .xls file to make analyse? for illustration,it could be possible to have more that 100warnings in one day thanks
F1Kimi Posts: 3 Rating: (0)
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12/13/2011 1:07 PM	Rate (0)
Aret Posts: 2348 Rating: (262)	Hello! Generally it's not a good idea to make archiving task on PLC. The reason is simple - your MMC would be constantly rewritting data, so your MMC would be exhausted by read-write cycles. >can I expand a memory?] You can expand load memory by means of larger MMC. Work memory is not expandable. >how can I download this datas from DB to .xls file to make analyse? simply - copy DB with archived data to PC, open it, then you can copy - paste to Excel. >for illustration, it could be possible to have more that 100 warnings in one day Ok, you need date and time (8 bytes) + signal state (1 bit) for each warning. Here you can go 2 ways: on rising edge of signal write DT to archive DB (SFC1+SFC20). Second approach - write continuously signal state for ex. in OB35 (you can chabge it's calling time to 1 sec in HW Konfig). With this you'll get 3600 bits/hour = 450 bytes/hour. Requires more space (if less then 50 messges/hour), but it's simplier to implement + you don't care about backward time syncronization of PLC. Summary: using SCADA or Operator Panel for this task seems standard, offered solution have it's drawbacks, so it can be recommended.
Aret Posts: 2348 Rating: (262)
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12/13/2011 2:21 PM	Rate (0)
F1Kimi Posts: 3 Rating: (0)	Hello! Thank you Aret! no,it was a misunderstanding, I have to record only one warning, but it can appear more than 100 times a day I only have to see (in that cycle) what was a condition of bit (piece bad or good) and normally a corresponding time. exist somewhere an example of similarly programm? I don't knowwritte this code alone
F1Kimi Posts: 3 Rating: (0)
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12/14/2011 9:34 AM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 8/8/2023 Posts: 6818 Rating: (1349)	Dear F1Kimi , Why don't you try using standard archiving programs? Log internal variables of S7 CPUs Best regards, Hamid hosseini
	Demo Channel on Youtube
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12/14/2011 1:06 PM	Rate (0)
F1Kimi Posts: 3 Rating: (0)	Thanks hdhosseini! yes, this could be a solution but... my problem is that I can't leave my pc connected to the cpu (it isn't in my factory). I am trying to do a program code which will be able to register apossible warning and register a time when warning happens (with saved bit - piece bad or good). My idea was to come in that factory once a week and look what happened to the machine. this machinedon't havean operator panel or scada, and for "no money reasons"I have to find this cheap solution. maybe I'm on wrong way but I think that this could be a good concept...
F1Kimi Posts: 3 Rating: (0)
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12/16/2011 11:24 AM	Rate (0)
hlapak Regular Member Joined: 11/25/2011 Last visit: 6/11/2022 Posts: 16 Rating: (1)	Hi F1Kimi, I would prepare a DB if I were you then and I would put two parts in it: The first I would make as a header - where to put the offset for the second part,number for entries,length of the struct and an int which you could use as a pointer. The second part I would do either as an UDT where to define day(byte),month(byte),min(byte),sec(byte), whatever data there what you might be also interested in and then put that UDT in the DB and specify how many entries you want. The second step shall be to detect the event and write the times in it (please refer to writing times from this link:https://support.automation.siemens.com/WW/llisapi.dll?func=cslib.csinfo&lang=en&objid=21222026&caller=view), as well the additional data you need. There are two questions which come then: when to erase the DB contents and what should happen if the DB is full - I haven't tried it yet but I think you could enlarge the DB by changing the UDT's entries in the DB and also correct the header data. Once again - this must be tested. I think it should be no problem and it should not affect the data in the DB. Hope you might clear out the idea. If not please post back Best Regards, izi

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12/16/2011 12:35 PM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 8/8/2023 Posts: 6818 Rating: (1349)	F1Kimi Thanks hdhosseini! yes, this could be a solution but... my problem is that I can't leave my pc connected to the cpu (it isn't in my factory). I am trying to do a program code which will be able to register apossible warning and register a time when warning happens (with saved bit - piece bad or good). My idea was to come in that factory once a week and look what happened to the machine. this machinedon't havean operator panel or scada, and for "no money reasons"I have to find this cheap solution. maybe I'm on wrong way but I think that this could be a good concept... Dear F1Kimi, It is practical , If you have limited number of binary signals (with limited number of state change occurrence) to monitor and just select important parts of "DATE_AND_TIME" such as "Month","Day","Hour" and "Minute" to reduce memory usage . You can create a kind of table in a DB with same element structure by using UDT.By using indirect addressing do the data management according the policy you like.For example, You can delete the oldest entry as you have new entry and no vacant element to assign. Best regards, Hamid Hosseini
	Demo Channel on Youtube
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