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Casanunder

Flex IO with a PC

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I am using Flex IO with an Ethernet comms adaptor to create a PC-based SCADA workstation that simply trends 20 analogue inputs. The client has specified FTView SE, ViewPoint, RSLinx Single Node and OPC DataHib all of which I've used before. My question is what do I need to read in the IO? Without a PLC or SoftLogix platform to create the machine tags, I'm stumped. Rockwell Support have told me I need to buy a Compact Logix to create the bridge, but the client assures me it can be done within RSLinx. Any help would be gratefully received.

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Hi Casanunder, Is that Flex I/O connected to a PLC? I think you need a PLC in order to read the I/O. Regards, Mushu

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Thanks for the reply, Mushu. The IO is connected via the Ethernet adaptor directly to the SCADA PC. There is no PLC or control involved in this system, we are purely monitoring, trending and reporting.

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I have never tried to pull data from Flex I/O without a PLC. But, you will need RSLinx to communicate between the PC and the Flex I/O. In RSLinx, try to create an OPC topic for the SCADA software to read I/O data from. I believe the OPC topic is the key. If A-B swears this is possible, take their tech support to task and ask for a Knowlegebase article on how to do so or provide more support than "yeah, it can be done".

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You would have to write Ethernet/IP code to directly poll the IO yourself. Best I can offer is that AB has issued some free source code for Ethernet/IP interfacing. You can't do what you are trying to do with RS-Linx without a PLC involved, but you might be able to do it if you can determine the correct CIP generic calls to make based on the AENT module documentation. This of course skips the OPC stuff too. In terms of time/money since you can get FREE Modbus and Modbus/TCP supporting software, I wouldn't bother to go the direction you are going in. I'd buy Wago, Beckhoff, or Acromag IO cards with Modbus/TCP and do it that way. Edited by paulengr

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Remember that it's "the client" saying this is possible. RA support is saying the opposite. When a client tells you how easy something should be, that's a sign you should be writing a time and materials contract. Probably what the client is thinking of is that you can read CIP objects directly from devices like FLEX and POINT I/O using RSLinx Classic. This is one of those "you can do it but we're not going to provide support if you have trouble" sort of applications. The hard part is the Analog modules, because they need to get configuration data. This is usually configured in Logix 5000 and sent to the module during the connection establishment. So, my questions are: 1. What is the part number of the analog modules ? 2. What voltage or current range are you planning to use ?

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Thanks to all who have replied here. It definitely appears we have been given dodgy info from the client (who in turn had originally been advised by Rockwell). Anyways - we have been talking to a software house who proposed to write a custom app to effectively create a OPC server that interfaced directly to the Flex IO, bypassing RSLinx completely. However, this came at such a cost that we have decided to do some testing along the Flex IO > SoftLogix > RSLinx > FTView route. As a colleague pointed out - "more layers than a Scooby Snack". Seems odd to have a SoftLogix layer installed that does nothing but apply tags, but there you go. Thanks once again.

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That is not true. The IO comes up "unconfigured". For digital IO this might be OK. Not true for analog. The PLC (whether Softlogix or hardware box) stores and provides configuration data for the IO.

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our company has done it on the 1794 without RSLINX interfacing to QNX based controller.... we have at least 100 sites with this setup.  of course there is no telling how much time and   effort went into making this happen.

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