FlexLogger to PLC connection

[BenG3]

At a previous company we used Veristand to control and acquire data over Modbus from a Rockwell GuardLogix PLC.  This PLC acted as the gateway device for CAN devices like power analysers and automotive inverters.  I'm looking to implement a similar thing, but a more cost-effective version using Flexlogger.  I'm pretty green with respect to Ni / LabVIEW etc and so please bear with me.

As I understand, FlexLogger doesn't support Modbus natively.  There is a 3rd party modbus over EtherNET plug-in that was for an ealier verison, but this may be cost-prohibitive at this point (am only setting up a development rig to test the control and acquisition code).  One option might be to establish the comms with FlexLogger over CAN.  I beleive the paid licence verison of FlexLogger can achieve this?  What is the simplest and lowest cost hardware needed to establish comms as all the IO is already on the PLC bus and so don;t need a cDAQ chassis or any devices such as this.  Is it going to be a USB-8502 device or similar?

Ideally the Modbus would be the preferred way, but i'm not sure of a route to that at this point, save for the 3rd part software (that does look quite good in fairness).  My reluctance on this route (aside from the cost) is that it is a locked system and any FlexLogger updates may render it requiring further updates and that is a risk that the company may/may not continue to support it, plus there is added time/cost if these updates are required on deployed customer systems ultimately.

[mnugent]

We had a similar need and connected FlexLogger to our PLCs (both reading and writing channels) by writing a custom FlexLogger plug-in using the LabVIEW SDK. The plug-in used Ethernet/IP reads and writes to connect to the PLC tags, so as long as the FlexLogger PC and the PLC's are on the same network, no additional hardware was required.

[BG_TSE]

Thanks MNugent, that is great to hear and exactly what I was looking to do.  I've not delved into Labview much really and so am still learning on that side and it might take me a bit to get to this point in being able to do that successfully.  Is your plugin available to look at / use at all please?  Failing that, any guidance on how to tackle this would be most useful.  Anything that woudl give me a steer or support would be gratefully received.

The PC and the PLC will certainly be on the same network, so I have no issues there.

Much appreciated for taking the time to post this as it gives me confidence that i'm not looking to do things that are not intended.

Thank you.

[mnugent]

Glad it was helpful.

Unfortunately, I am not allowed to share any code or built packages without going through a whole export control process. 

I will say it is one of the simpler FlexLogger plug-ins we've developed and would not be difficult to replicate. As a high level overview, we pass a list of tag names and the PLC's IP address into the Plug-In as parameters from FlexLogger. In the plug-in, we use Ethernet/IP (which is a component available in LabView's Industrial Control module) to read/write to the PLC tags. The Plug-In then sends those values back to a FlexLogger channel.

Without any LabView prior knowledge, extending FlexLogger with the Plug-In SDK might be a tall order, but I will say the SDK is well documented and comes with templates that get you 75% of the way there.

You could probably also do this with the FlexLogger Python API. The API provides well documented methods and example code snippets for reading and writing values to FlexLogger Channels. Your python code then just needs to handle moving those values to the PLC. I don't know what Python package would be used to directly read/write from the PLC, but I can guarantee a method exists.

[BenG3]

Thank you for the insight. I will try to go though it and if nothing else, I’ll learn stuff. If the Export Control stuff is ever made easier then please let me know as I’m eager to get Modbus as a viable option without the requirement of costly hardware. 

thanks again.