Software vs. Hardware PLC?

I am looking at both possibilities - Hilscher board, and open source (do-it-yourself) Ethernet/IP communication.

Stated RPI for this sensor (in configuration which we would be using) is 1 ms. I see no specs regarding latency - but shouldn't I assume that sensor would not have RPI faster than inherent latency?

The open source option still seems like a good option. Ethernet/IP packets have clearly defined formats (and RTX real-time already has Ethernet sockets). I am just looking now how to attach controller/sensor tags - but I can't understand why it should be that difficult. Let's see how quickly I have to eat my words...

Total_newbie said:

I can't understand why it should be that difficult. Let's see how quickly I have to eat my words...

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One thing is getting your scanner application to communicate with this sensor. However, strictly speaking, any vendor of EtherNet/IP scanner should register its scanner with ODVA prior to selling the product. That means that your company should become an ODVA member (get your vendor ID) and that you need to have your scanner application pass the EtherNet/IP conformance test. This is where it can get complicated if you use open source, as these stacks are not always maintained. Of course you can develop your application and not register the scanner but this would not conform to ODVA policy and at the very least your customer should be informed. A product such as the Hilscher board will have its conformance test certification. I can personally vow on the difficulty of passing these tests as my company develops firmware for EtherNet/IP adapter devices. If this scanner you are thinking of developing would be part of a large installation, the end-user may demand that the device support address conflict detection (ACD) for example. This one is really tough. My advice is that you find out whether it is acceptable to provide a non-registered product to your end-user. If I was the end-user and the scanner is to be used with other EtherNet/IP devices I would not accept such a product.

All of that makes sense. There is no sense to try and reinvent the wheel. And particularly since Hilsher board has APIs for RTX - this should be the most straightforward route.

I am just trying to find out from Hilscher whether they know of anyone else who has tried to get data from device at 1000Hz using Ethernet/IP. Device specs say that sensor is capable of sending at this rate, but I want to make sure that there won't be any delays on receiving end.

Anyone out there have experience with this? Or have seen code to read a single tag from device? (Looking at Hilscher API - this doesn't seem that easy...)

Thanks...

https://www.hilscher.com/fileadmin/...pdf/EtherNetIP_Scanner_Protocol_API_14_EN.pdf

Total_newbie said:

I am just trying to find out from Hilscher whether they know of anyone else who has tried to get data from device at 1000Hz using Ethernet/IP. Device specs say that sensor is capable of sending at this rate, but I want to make sure that there won't be any delays on receiving end.

Anyone out there have experience with this? Or have seen code to read a single tag from device? (Looking at Hilscher API - this doesn't seem that easy...)

Thanks...

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Theory and practice is different. Theory would say it is possible. My practical experience would say it is not possible.
Try to read file below.

https://www.politecnica.pucrs.br/pr...A_ADICIONAL_-_EtherNetIP_enet-ap001_-en-p.pdf

I think CC link IE TSN is capable to do it without problems, but it is quite new protocol. (link below)
https://us.mitsubishielectric.com/f...rk-related-products/cclink_ie_tsn/performance

CC Link IE TSN is a new protocol, there are not that many remote IO that support this protocol, and there is only one master which is the Mitsubishi Electric iRQ series or FX PLC. There are not as yet third-party PCI or PCIexpress boards for this protocol.

With EtherNet/IP with an RPI of 1 msec at least in the wire the scanner and adapter can exchange information at 1 KHz, But there is a delay on the PCI side, and most importantly, can the sensor send new data every 1 msec?

AlfredoQuintero said:

CC Link IE TSN is a new protocol, there are not that many remote IO that support this protocol, and there is only one master which is the Mitsubishi Electric iRQ series or FX PLC. There are not as yet third-party PCI or PCIexpress boards for this protocol.

With EtherNet/IP with an RPI of 1 msec at leas in the wire the scanner and adapter can exchange information at 1 KHz, But there is a delay on the PCI side, and most importantly, can the sensor send new data every 1 msec?

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I agree with everything that you wrote, except that I think that Gigabit Ethernet would do the job for that application and that he does not need PCI or PCIexpress.

Anyway, judging from datasheet, Profinet would not do a trick as it is just Profinet, not Profinet RT.

I really appreciate all the helpful pointers - even if they do raise more questions about what I can really expect from this device. Gigabit ethernet sounds great - but without using PCI card, I would appear to be back to my original issue - which is how in the world do I read tags from this device? Hilscher card does provide all the API. If I don't use this - I am back to writing protocol from scratch...

goghie said:

I agree with everything that you wrote, except that I think that Gigabit Ethernet would do the job for that application and that he does not need PCI or PCIexpress.

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EtherNet/IP, Profinet IO RT, EtherCAT, all these protocols can handle RPIs of 1 msec at 100 Mbps easily.

theColonel26 said:

This is why there is a big price jump between consumer grade laptops and business grade laptops. Having use both for work I will shell out the extra money for the Business grade every time.

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Out of curiosity, what is the difference? My home laptops often seem better in every way at comparable price points, including reliability.

rupej said:

Out of curiosity, what is the difference? My home laptops often seem better in every way at comparable price points, including reliability.

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What Model to do have and home and what model to you have at work?

Screen viewing angle, better anti glare coating, keyboard quality, better track pad drivers or sensors (not sure which), generally more reliable firmware (no flaky sleep and hibernation), and general case and build quality is heavier duty. Every consumer grade laptop I have ever own has had the plastic case break around the lid hinges after a year or 2. Never had this issue with a business grade laptop.