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nasir_ash

CQM1H -SCB41

51 posts in this topic

Well as you can see the Modbus command is send, and if you know Modbus you can brake it down easily. Every message is composed like this: [<SLAVE ID><FUNCTION><DATA><CRC>] So for your data: 01:Slave 1 06: Function code 6 (Set single Register) 0001: Data address 1234: Set value D57D: CRC Is function code 6 and this address supported by the VFD?

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Dear mate fucntion code 06H is used to change the frequency please find the attached jpg file now i change the set value to 01f4 i.e 500 = 50 HZ please find the tarce again, but one issue is more, bit 207.12 (NC) beomes gary when Execution bit 20.00 turn on and com2 light blinks and OFF, so 207.12 also remain OFF. as per trouble shooting guide the bit 207.15, or 207.11 is force so i release all the force. but the problem remain same. as you see the trace i am not getting feed back for Inverter. please suggest? TRACE3.zip

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Does the frequency value you send lie within the permittable frequency range of the drive? I know if you send a frequency outside this range to a V1000, it simply goes into error. Does the VFD have a Operator panel with display? Does it show the frequency reference? Not sure what you mean with the bit going "gary", try to explain better... By the way I don'n have CX-Protocol running on my Android phone yet so I am not able to check the trace file...

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Dear PDL the maximum requency set is 60Hz. yes VFD have a display panel and it shows 0.0Hz, and display is adjusted to show frequency. actually my communication is aborted just after the 207.12 is OFF (gray mean OFF, green mean ON) when i take a trace so trace shows only data sending. we have to control that 207.12 until communication is completed. please have a look on flags control by the 207. and suggets regards NASIR

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Still not clear to me if your first attempt using function code 05 to set a bit worked or if you just moved on to function code 06 to see if it works but it looks like your problem is simply that the PLC does not reveive an answer and therefore 207.12 doesn't turn off. With write functions it expects an echo of the send command. Have you checked wiring, no swapped lines, termination (not sure what distance we are talking about here) etc? Else use Modbus simulator software to test both sides independently, a slave simulator to simulate the VFD and then you will see the response in your trace and a master simulator to simulate your PLC and try your commands, usually that brings up the problem.

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Dear PDL used coed 6 to test if it works or not. but in both the case problem remain same. i alreday turn off ECHO by turning ON 207.07 cable Length is almost 1 meter. termination is OFF, as i am using only one VFD. please help how i get the modbus simulator for slave and master? regards NASIR

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I use these software simulators together with a 232/485 converter on my laptop. For 30 days you can connect 10 minutes, after that you have to buy a license. It is worth the money, helped me several times in similar cases. http://www.modbustoo...om/download.asp p.s. using quote tags is real easy, just highlight a piece of text and hit the quote button. But if you select reply on the post itself, the quote tags are inserted automatically...I have been fixing your quote tags throughout the topic...

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Dear PDL in my laptop i have rs232, How i test Rs422 port on SCB41. similarly i have only rs485 port on VFD. how i check this by laptop? regards NASIR

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Come on NASIR, I mentioned it in my previous post. Use a RS232/485 converter! At PLC side, you can also swap ports on the SCB...

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Dear PDL i dont have converter right now, let me arrange then i iwll give feed back of VFD tests. can you please explain what do you mean by SWAP PORTS ON SCB? Regards NASIR

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The original PMCR was setup for RS232. (I checked.) If you are going to use the PMCR for RS485 or RS422, you must set the control for Modem which allows the transceiver to change state from RXD to TXD. I have set the control to modem in his latest PMCR. Here it is zipped: Modbus_RTU_Master one seq705 with Control Set.zip

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Well there you go, I didn't know that either. Sounds like the solution to NASIR's problem!

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Dear Friends Now after downloading the NEW PMCR the improvement is that VFD is showin error E-60 " mean communication error (when communication watchdog timers time out") please find the atathced trace now i am getting feedback form VFD. please also find the ladder to re-check if there is any issue. and PLC is setting bit 207.13 ON, with FAL 06 alarm regards NASIR testing modbus.cxp TRACE with control set.zip Edited by nasir_ash

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1. Stop adding whistles and bells to your program and keep it simple with just 1 command to execute until you are sure it works and you understand why it works. Why have you added a fixed CRC to the send command? 2. Start commenting your program and use symbol names if you want people to help you out. 3. Let us know what your have done and investigated yourself to find out what is wrong, to give other people the impression that they are not the only ones working on your problem, instead of just posting the problems you encounter.

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Dear PDL please find the attahced ladder with comments so esay to understand. it my mistake that not use comments. as per VFD manual, increase the coomunication error time out to 0.25 sec alarm appear then increase to 5 sec. when ever the PMCR execuates, after 5 secs the alarm come on inveter. please help i dont have so much information on modbus ....please dont be angry, i have not so much information on MODBUS, that why i am requesting help on every step. Hope you will understand. Regards NASIR MODBUS WORK.cxp

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No joy in life in this one...

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Dear JAY And PDL NOW i can do comunication b/w VFD and PLC. please find the attahced TRACE. Now i have a little problem when writing to Holding register via sequence # 706. writing to change the frquency. but it not changing. can you please help a little. Here i will say thanks to both of you for such a great help. Cheers!!! regards NASIR TRACE OK .zip Edited by nasir_ash

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Hi NASIR, let me ask you a question. Describe to me what message you see in the trace. Then ask yourself if this function code will work to change the frequency.

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Dear PDL this trace shows BIT turn ON. i sent it to you that its now working. because lastly is was not giving the responce of inverter. so when i start getting the responce, sent it to you. the problem i mention here that freq is not changing, it my mistake that i am tranfering frquency more that 60 HZ. my multiplying factor is 1.5HZ and in the manual it was 0.1Hz that why i am not getting respoce from VFD ( 500 * 1.5 = 750 > 60.0 Hz) Now friend i am getting respoce of frequence also. thanks for your great help ...... regards NASIR

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Well I am glad for you that it is working. Hopefully next time you will be more clear and give a better description of your efforts.

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Better you than me....

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Hello, I also have a problem with the modbus software. I try to read an address an 207.12 doesn't turn off. I tried a ladder exactly as in the zip file. i use dm0090:2704 91:4 92:1 (node) 93:119(address) 94:2 i tested the modbus slave with modbus poll and the device responded correct. i also use rs485 I read in one of the previous messages the protocol was for the rs232 port and not for the rs485, is this so, what is the difference? Regards Eddy Edited by Eddy Dillen

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Please post zip file. I don't know what code you are using. If it is PMCR, please post the macro, too.

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Hello I used the modified (by myself) macro file that Jay posted on 07 02 2011.pmcr.cxp thanks for the help Regards Eddy Modbus_RTU_Master with 10 with control set.zip Edited by Eddy Dillen

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