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FET_Destroyer

CJ2M master and CJ1M slaves

15 posts in this topic

Hello Guys, I need to build a system that have 3x CJ1M. I need to have data from that PLCs in a computer. I think in two solutions; #1 Buy an expensive etn21 board for each plc and then connect them to the network (quick, easy but expesive) #2 Another solution, and cheaper (I think) is to buy a CJ2M-CPU33 plus option board CIF01 RS232 serial plus SCU21 board with 2x RS232 which give me a total of 3 RS232 ports, all CJ1M have one free port. This were the solutions that I found but I'm not happy with it, does anybody has a better or different solution for this? Regards Edited by FET_Destroyer

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Easiest is to use all CJ2M-CPU33 and set up auto transfer in all PLCs. There are fault bits and all available. You can set up a maximum of 16 PLCs this way but there is a limit of I think 640 words.

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Right as usual Bob. This is the obvious solution. CJ2M-CPU3x has built in Ethernet IP.

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I think too many people want to fiddle about saving a little money on hardware. The amount of time then spent fiddling about in time and labour is not worth the grief. Use something that is easy to use and set up/maintain and you are a mile in front and onto the next job far quicker. Look for efficiency not hardware cost. My 2 cents worth.

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I agree with Jay and Bob. A CJ2M-CPU31 is about equal in cost to one day's work. There's no way that you would get an elaborate RS-232 network working in just 3 days.

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Hello Guys, If I start the project from the begging I will have all cj2m-cpu33, but I already have 3 machines with CJ1M, with no ethernet, and I need to read data from that devices. @BobB, tell me more about the feature of auto transfer, how can I set it up? (Not for this project but for sure will be useful in the future). Regards

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Just thought about a possible option. Depending on the amount of data that needs to be exchanged, what about Serial PLC Link? This will work with the CJ1M and CJ2M according to the manuals (W394 and W473). This would allow up to 10 words per processor. This may be what BobB was referring to as auto transfer. This would require using the CJ1W-CIF11 RS232 to RS422/485 converter on the serial port of the processors. You should download these manuals (W394 and W473) and search for Serial PLC Link. Hope this will help.

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I agree with BobB and Jay. No point saving a little on hardware cost and then spending days making things work. In the past someone decided to use the ZEN programmable relay to save some money. When there was a problem with the machine, nobody had the software or the knowledge for troubleshooting it. So the machine was down for 1.5 days because someone decided to save ~$200(?). Anyway, there is a EtherNET IP wizard in the network configurator that allows you to automatically exchange data between PLC's that are on the EtherNET IP network. It's really easy and I have used it without issues. I think this is what BobB was referring to?.

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Why not buy CJ2M-CPU31s to replace the CJ1M CPUs? About as cost effective as buying additional EIP21 modules for the older CPUs.

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My interpretation of what the OP asked is that he wants to read data from each PLC into a single PC. A simple way of doing this with what he has is to just read via serial. His approach was to read from each PLC into a 'concentrator', then have a single PLC provide the data to the PC. I guess it depends on the length or runs to each PLC from the PC? If he has Ethernet adjacent to the PLC's, he could just use a serial server instead. That would be a cheaper option than ETN's & changing the CPU's. Whilst I agree, Ethernet based CPU's would be better, but it sounds like this is an existing setup that the OP is working with.

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Yep - datalink wizard is what I was referring to. I still think it would be a darn sight easier and quicker to replace the existing CPUs with CJ2M - even CPU31 would be fine. Serial is a PITA and very slow too! Could not be bothered.

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Bob: It's just a case of integrators like you and I where time is money and an end user who can hide the development labor but needs to get a PO past purchasing.

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Hello Guys, Thanks for all the replies. I think in the end I will buy 3 cj2m-cpu31, the modifications are minimal, maybe just exchange the cpu unit and configure the datalink wizard. Regards

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But, if you only want the data to a central computer, there is no need for the DataLinks. Unless, you want to share data between PLC's for control or something...? What are you using on the PC to connect to the PLC's? Edited by lostcontrol

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Hello, Yes, it makes no sense to use now the datalink wizard. The main goal was to use a plc as interface, but now, since all cpu will have ethernet I can connect them directly to the PC. Regards

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