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pattyo

EIP21 or ETN21 with a CP1H?

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Hi guys, I'm ready to purchase an ethernet unit and need help narrowing down my selection. I believe what I want is either the EIP21 or ETN21. Unfortunately, my knowledge of PC-PLC networking is not that great. Currently on a couple machines we have a PLC primarily operating the equipment, and a PC connected via USB that sends and receives word/bit data through the active X control through a visual basic user interface. This way, if the computer restarts or crashes, the machine can keep working (without HMI) until we get the PC worked out. It's kind of slow, but it works when there is not too much data transfer going on. We tried before to hook up a CIF41 ethernet plug-in and connect it to our network, but the communication was spotty and unreliable we assume due to too much network traffic. The plan is to upgrade to a "real" ethernet unit that can actually filter out network traffic, and hook the machine directly to the network. Unfortunately, we cannot have a dedicated equipment network at this time, so everything (PCs, printers, etc) are on the same physical network. It would also be nice to have things like a server capability in case we decided to create an intranet based HMI, but this is not necessarily required. I think it would be cool though. Basically, the primary goal is to be able to plug our PLC into the network and have a reliable, fast PC-PLC interface with a PC on the network running our visual basic software. No more USB cable. I'm leaning towards the ETN21, simply because I don't understand the added features of the EIP21. Any tips? Thank you!

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I have faced the exact same situation as you describe. The CIF41 provides great throughput when used on a somewhat isolated network, specifically a network without a lot of extra IT protocols and features like Rapid Tree Spanning and others that broadcast a lot of non PLC related packets.I have also solved those situations by using either an EIP21 or ETN21. For your application, either one would work, but as the ETN21 has more buffers for the FINS protocol, this may give it a slight edge over the EIP21.

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Thanks for the reply PMCR. Based on my research, the CIF41 ended up being no more than a ethernet-serial convertor, and the data rate is actually slower than USB 1.1. It works alright when the network is isolated as you mentioned, but cannot handle an actual network with a lot of other devices. Could you explain in layman's terms just what the differences between the ETN21 and EIP21 are? I don't have experience using the FINS protocol either.

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From a FINS perspective, the ETN21 and EIP21 are very similar. Both can send and receive FINS commands. The ETN21 was designed many years before the EIP21, and supports FINS, Email, Socket Services, and a few other IT type functions. The EIP21 was designed to support the EtherNet/IP protocol in addition to FINS. So the EIP21 can act as an Originator (master) to other EtherNet/IP Target (slave) devices such as inverters, IO modules, bar code readers, vision systems, and other EtherNet/IP protocol devices. The support for the EtherNet/IP protocol is the main differentiating factor between the 2 modules.

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So, considering the ETN21 was produced long before the EIP21, is the EIP21 better, or just different? They actually cost the same exact amount - I was quoted $1100 each. Side note - I am using a Keyence vision system that supports Ethernet/IP but I hadn't planned on using that feature yet. I'm not sure I can justify setting up this type of network considering our facility is pretty small and each machine has its own dedicated computer already. It's also a mixed network with all the computers and stuff so there is a lot going on. Does anyone have any resources for learning more about Ethernet/IP? I'm trying to do this right, but don't have much experience with it and no one here knows anything about it. Thanks for the help so far :)

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Great questions. I would not say that either or is better. The ETN21 was redesigned recently (from a hardware perspective) and shares most of the internal design of the EIP21. They really just have 2 different purposes. For pure FINS applications, either one would do very well, with an ETN21 having a very slight advantage. If you think that you may venture into the world of EtherNet/IP, I would choose the EIP21, even if you never end up using EtherNet/IP. EtherNet/IP in a nutshell: Omron EtherNet/IP master modules (EIP21) can make what Omron calls Tag Datalinks (generically called Implicit Messaging) connections to Omron and 3rd party devices that use EtherNet/IP as a protocol. You set up Tag Datalinks through the Network Configurator for EtherNet/IP, which is part of CX One. You map the IO from the remote device into PLC memory, and the data exchange is automatic, and requires no ladder code beyond massaging the data to do what you want. Here is the only catch: you need a well written .eds file for your device. I say 'well written', because there are many devices out there with .eds files that are incomplete, inaccurate, or simply nonexistent. The biggest manufacturer of EtherNet/IP Scanners (Rockwell Automation) does not typically use the .eds files to establish communications to a device, so many vendors have created .eds files because they are required to by ODVA specification, but in reality, they have never been tested by a device such as an Omron EIP21 card that uses the information in the .eds file to make the connection. Most of the time we can massage the .eds file to overcome any problems, and once this is done, you will not have any problems. In the rare case that a vendor does not have an .eds file for their device, or the .eds file does not contain any connection information, communications to the device by EtherNet/IP will not work.
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Thanks for taking the time to help me out!

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The biggest difference is EIP21 does not support Socket Services. Therefore, if you only need to have PC to PLC communication then ETN21 would be ideal for your case. EIP21 is good for setting up communication between a PLC and Ethernet/IP-enabled devices.
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Using ETN21, how can i access PLC (CJ1M-CPU23) remotely from PC via web browser? For the same purpose EIP21 can be used or not?

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No webserver in either!

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