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Help Collect data from PAC3200 via Modbus TCP

Created by: anhtuan_ntc at: 8/4/2009 5:52 AM (19 Replies)

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8/4/2009 5:52 AM	Rate (0)
anhtuan_ntc Posts: 54 Rating: (0)	Hi, Now i am trying to collect data from PAC3200 via OpenModbus TCP to S7 300 CPU317-2, CP343-1, connection is good, CP is client with port 2000,...., any PAC3200with port 502, the program like axample CPU Client. I tried with a PAC3200, address 1..125 in VAT test,I can see data in DB11: DB11.DBD0: U1n, DB11.DBD4: U2n,...from 1..125, butI don't know how to see data ofnext registers, from 126..250, 151..375,... Pls show me how can I display value of next registerin DB12, DB13,...? How can I get all data in only 1 DB (like DB11 with range: 1..800, type:WORD)? Regards, TuanNA.
anhtuan_ntc Posts: 54 Rating: (0)
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8/4/2009 8:51 AM	Rate (1)
YngSoul Posts: 15 Rating: (1)	Hi anhtuan_ntc, The modbus protocol allows you to read only 125 Registers per telegram. So, if you need to read more than this amount, you have to send it in several telegrams. For example if you need to read 500 registers starting from address 10 you can do it like following: First telegram: Start_address= 10; Length= 125 ; Secondtelegram:Start_address= 136; Length= 125 ; Third telegram: Start_address= 261; Length= 125 ; Fourth telegram: Start_address= 386; Length= 125; You can only send a telegram wenn the previous one is done, wich means you send one telegram and wenn DONE_NDR is True then you send the second one. it doesn't matter if the data are in one DB or in severals. you can receive all your data in only one Db. so if you need that all your data be received in DB11( from 1000 register for example) you need to parametrize the DB 11 big enough in OB100; for example: Start_1= 1; End_1= 1001. I hope i could help you. Good luck! YoungSoul
YngSoul Posts: 15 Rating: (1)	Last edited by: YngSoul at: 8/4/2009 10:58 AM
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8/4/2009 11:41 AM	Rate (0)
anhtuan_ntc Posts: 54 Rating: (0)	Hi, I tried, but it is still not collect data from 126, pls see my project and give me some advises. TuanNA. Attachment Newhw2.zip (932 Downloads)
anhtuan_ntc Posts: 54 Rating: (0)
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8/4/2009 4:19 PM	Rate (0)
Kaulquappe Posts: 3093 Rating: (323)	Hi TuanNA, why do you use different UNIT numbers? I'm not sure, wheather PAC can handle that. Use always the same UNIT. You change the input parameter of FB MODBUS at the beginning of OB1. It is not recommended to change the parameters while a job is running. Wait for DONE_NDR before you set the parameters for the next job. Regards, Kaulquappe
Kaulquappe Posts: 3093 Rating: (323)
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8/5/2009 6:28 AM	Rate (0)
anhtuan_ntc Posts: 54 Rating: (0)	Hi, I tried with UNIT=2 and I only do the second order telegram after DONE_NDR=1, I don't know why I can get 1-125 first value of PAC3200but can not read the next, Have you ever connect to PAC3200 by Open Modbus TCP via CP? Pls give me some advises. Regards, TuanNA.
anhtuan_ntc Posts: 54 Rating: (0)
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8/5/2009 9:21 AM	Rate (0)
Kaulquappe Posts: 3093 Rating: (323)	Hi TuanNA, I already did a project with PAC3200. I always used UNIT=1. What are the outputs of FB Modbus when reading the second telegram? Do you get the ERROR bit? What is the value of STATUS? Regards, Kaulquappe
Kaulquappe Posts: 3093 Rating: (323)
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8/5/2009 10:05 AM	Rate (0)
anhtuan_ntc Posts: 54 Rating: (0)	Hi Kaulquappe, I think the problem is not about Unit =1 or 2, Ihave exchanged between 1 and 2 but have no result, When I insert the second order telegram for next register and use VAT to monitoring, I have no result, it does not run, whenI set ENQ_ENR=1, it appeared error A01Cas attachment file in this thread, if I do not call the second order telegram, it still work well, Did the CPU don't recognize the nextaddress of register? TuanNA. Attachment pic2.JPG (910 Downloads)
anhtuan_ntc Posts: 54 Rating: (0)
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8/5/2009 11:21 AM	Rate (0)
YngSoul Posts: 15 Rating: (1)	Hi anhtuan_ntc; according to the screenshot; you get as an answer for your second Telegram an exception code. this one, is caused by an attempt to an invalid area or rather doesn't exist. verify if the address you need to read is not Write-Only on the Pac or if it even doesn't exist. YoungSoul
YngSoul Posts: 15 Rating: (1)	Last edited by: YngSoul at: 8/5/2009 11:22 AM
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8/5/2009 11:45 AM	Rate (0)
anhtuan_ntc Posts: 54 Rating: (0)	Hi YngSoul, I see all data from PAC3200 canberead, some of them isRead/Write datatype and I see in the table of data, it exist following the register in continous with step is 2. You can see in the data table of PAC3200 attachment with this thread. I think when SIEMENS make PAC3200 with Modbus TCP and point all data in table, that mean it can run with full function of Modbus protocol like connection with CP343-1 and Open Modbus TCP, but the problem is we must read data by step 125 register in each order telegram while we don't have much of trouble shooting guide for it. I am still waiting for... Hope to hear from you soonest, TuanNA. Attachment Output1.pdf (876 Downloads)
anhtuan_ntc Posts: 54 Rating: (0)
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8/5/2009 12:06 PM	Rate (0)
Kaulquappe Posts: 3093 Rating: (323)	Hello TuanNa, as you can see in the PAC manual on page 40: NOTICE Error in the case of inconsistent access to measured values Please ensure the start offset of the register is correct when making read accesses. Please ensure the start offset and the number of registers are correct when making write accesses. If a value consists of two registers, a read command applied in the second register, for example, will generate an error code. SENTRON PAC will also output an error code if, for example, a write operation ends in the middle of a multi-register value. So change your request regarding to the notice above. Regards, Kaulquappe
Kaulquappe Posts: 3093 Rating: (323)
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