Red Lion Graphite system variables and tags

IanfromOz

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Join Date
Dec 2018
Location
SE Qld, Australia
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Hi All,

I'm planning to use a Red Lion Graphite system to control and monitor a small pilot plant with perhaps 100 - 120 I/O plus 6 or 7 VSDs via comms.
My background is larger DCS systems so I'm struggling a bit to get up to speed with the way PLCs and HMIs work. I chose the RL Graphite as their HMIs seem very well regarded and integrated with the Graphite controllers and IEC61131 Control functions. The area giving me grief at the moment is the interactions/relationships between physical I/O, Data Tags and the local variables & Project (global) variables in the IEC61131 Control engine.
In the Control engine:
* I have a User Defined Function Block (UDFB) with 8 parameters that I wish to use numerous times in my project.
* I would also like to divide my control logic into a number of different 'Main' programs for modularity and readability.
* I will define Data Tags for all the parameters of each instance of the UDFB and all physical I/O so they accessible throughput the HMI.
* I also wish to access some of these parameters in different Control programs.
* If I defined local variables in each Control program with their ‘sources’ being the same Data Tag, will this link the two local variables together? For example, say I have a local variable called XV101PV (this is the opened/closed status of valve XV101) defined in Prog1 and in Prog2. And both instances of XV101PV have their source defined at Data Tag ‘Project.XV101.PV’ (it’s written in Prog1 and read in Prog2), will the Prog2 local variable track the Prog1 local variable? And if so, is this an appropriate way to pass the value?
* OR does every instance of a parameter that I may wish to access in different Control programs have to be defined as a Project (global) variable? If so, there will need to be quite a lot of them, which I thought was considered poor practice.
* OR am I going about the whole thing the wrong way?

All help most appreciated.
 
I don't think many people have used the control module. I have studied it briefly, but have no actual experience with it.
Fair enough and thank you.

In more general terms I believe Red Lion 'Main Programs' are what IEC61131 calls top level Program Organisation Units (POU) of the 'Project'
So, generically, what is considered good practice when a data item set in one POU needs to be referred to in another? Should such items always be declared as global (Project) variables or is there a better (smarter) way to pass data between Programs?

[I'm finding this difficult as in my DCS background (Yokogawa Centum most recently) as soon as you give something a Tag Name, from a single DI/O point to a complex controller block with 30 or 40 parameters, it is instantly 'global' anywhere in that Field Control Station (= big PLC). You can reference any data item anywhere by Tag Name.Data Item.]
 
I would always make any real world I/O tags global. If you are building structures based on those tags, and their elements need to be accessed across multiple programs, that by definition means they need to be global. There may be some other technique to share the tags, but it likely adds more complexity than simply making them global. I would only use local variables for things that are for exclusive use by the program in which they're used.

The concept of local tags is relatively new to the PLC world. Hell, make everything global. When you have it all working, go back and see if there would be any advantage to changing some of them to local.
 
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I just went to the Red Lion site and read about that controller. Very impressive. I might buy one just to play with it. 300 protocols built in.

Communicate with over 300 major industrial protocols
Support up to 18 simultaneous protocols
Translate between serial, USB and Ethernet devices
Manage multi-vendor environments with ease
OPC UA Client Driver
OPC UA Historical Access
Built-in MQTT connectors accelerate IIoT projects with point-and-click simplicity
  • Google Cloud
  • Amazon AWS
  • Microsoft Azure
  • Sparkplug
  • Inductive Automation Ignition!
  • Ubidot

Store and Forward Buffering for Cloud Connectors

That is crazy. I must own one of these.
 
Hi Paul,

As far as I know Automax had global and local tags from its inseption and that was a long long time ago.

Alan

I should have said it differently. The point I wanted to make is that until the most recent platforms, very few PLC programs used any local scope tags. I never saw that feature used in the PLC-5 or SLC, but it is possible to mark data files as program scoped.
 
Thanks Gentlemen (and Ladies? - shouldn't assume...).
I'll see if the local RL agents can explain this to me. They've been very helpful to date, despite the fact that I've yet to buy so much as a single crimp terminal off them. I try not to to stretch their goodwill, so thought I try on here but it seems Graphite Control use is in its infancy.
 
I looked into the Control Module to use with a Graphite 09 about 2 years ago. I was told that the programming environment for Control was a "By Out" item for RL and the support group was not up to speed on it at that time.

I decided to not be a Guinea Pig for them and went a different direction. I would hope that after over a couple years later they would have a better grasp on the product.

If you do find out more about the system please let us know.
 
I looked into the Control Module to use with a Graphite 09 about 2 years ago. I was told that the programming environment for Control was a "By Out" item for RL and the support group was not up to speed on it at that time.

I decided to not be a Guinea Pig for them and went a different direction. I would hope that after over a couple years later they would have a better grasp on the product.

If you do find out more about the system please let us know.

I downloaded the manual specifically to look at the SQL Queries section. I was hoping it would allow calling stored procedures and also to be able to iterate through a dataset in some detail. it looks like it doesn't support it. There may be other ways to accomplish it though.
 
I downloaded the manual specifically to look at the SQL Queries section. I was hoping it would allow calling stored procedures and also to be able to iterate through a dataset in some detail. it looks like it doesn't support it. There may be other ways to accomplish it though.

Red Lion Crimson manuals are notoriously sparse. They seem determined to keep under a page limit or something. They cover everything, but not thoroughly. I would not be surprised if there are separate technotes that give further detail or things that are in the tool set that are not discussed on paper.

I don't know enough about SQL to attempt to check. That is one of those areas that I know I need to be better educated about, and I am pretty sure at some point I will learn more.

SD_Scott, you should download the software (if you haven't already) and explore it. You might find what you are looking for there.
 
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Red Lion Crimson manuals are notoriously sparse. They seem determined to keep under a page limit or something. They cover everything, but not thoroughly. I would not be surprised if there are separate technotes that give further detail or things that are in the tool set that are not discussed on paper.

I don't know enough about SQL to attempt to check. That is one of those areas that I know I need to be better educated about, and I am pretty sure at some point I will learn more.

SD_Scott, you should download the software (if you haven't already) and explore it. You might find what you are looking for there.

I will definitely download it. With the controllers ability to connect to Azure and Amazon AWS, I would assume it has some fairly powerful database features. I will look.
 
I will definitely download it. With the controllers ability to connect to Azure and Amazon AWS, I would assume it has some fairly powerful database features. I will look.

Get 3.0 too. It doesn't have all the latest and greatest features and hardware support, but it does have the handy dandy emulator which you can use for development and map through your PC com ports to talk to real hardware. The logging, email, SQL and FTP features are crippled in the emulator, but for general all around HMI development, that emulator is the bomb.

I believe 3.1 emulator is going to be enabled soon. As first they said there would be no emulator. Then they said they are working on making it better and less error prone. Then the latest version of 3.1 actually has the emulator button and settings link (but they're grayed out).

I still develop in 3.0 a lot so I can fully test everything without having to use real hardware. Once I have it all tweaked, and tested with the emulator, I will open 3.1 and import it, convert it to the right hardware and download to the HMI. I use a lot of the CR3000 series lately and a few Graphites. I have a few dozen Kadets in the field too. I have not had any hardware failures (except the one G304K2 that got dropped in the shop and cracked the screen).
 
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