ARIES PLC110[M02]-MS4, HMI, OPC and SCADA, or how much Chamomile tea a person needs. Part 1

Good afternoon, dear readers of this article. I am writing this as a review.

A small warningI want to warn you that if you immediately understood what it was about from the title, I advise you to change the first item (actually, the PLC core) to anything from the price category one step higher.
No amount of money saving is worth that amount of nerves, subjectively.

For those who are not afraid of a little gray hair and the amplitude of a nervous tick, later I will describe in detail how this technological miracle was created. In this article, a brief analysis of the project with a certain degree of criticism.

Origin. Formulation of the problem

Actually, I work in a design office, and we test automation equipment for integration into our turnkey plants. Recently, OWEN equipment arrived at the warehouse and it was decided to assemble a test bench from it:

• PLC110[M02]-MS4 (Executive environment MasterSCADA 4D)
• Operator panel SP307
• Module for universal input of analog signals МВ110-224.2А
• Load cell signal input module MV110-4TD
• Electrical measuring module MV110-220.3M

Structure of the system was chosen with the delimitation of networks according to their purpose:

1. Modbus RTU based on RS-485 - PLC communication with slave devices (modules, frequency converters, smart sensors, HMI panel SP307), PLC network master.
2. Modbus TCP based on Ethernet - Communication of different PLCs with each other and with the OPC server
3. The PC server of the OPC and SCADA systems is simultaneously a gateway between two different networks (Corporate LAN of the enterprise and Modbus TCP network of controllers (two network adapters with data routing using standard Windows tools)
4. Corporate LAN has Internet access through a proxy server

The structure of the system in general is shown in the image below:

Built-in functionality

• Collecting and forwarding data from the PLC to the OPC server
• Local control and monitoring via HMI panel
• Control and monitoring from SCADA via OPC server
• Control from any PC from the LAN of the enterprise and via the Internet using a SCADA client
• Connecting mobile OPC monitors via LAN and internet
• Of course, archiving and generating reports

Seems like they didn't miss anything. There is a general description of the system, and now, in fact, on the topic (I will describe the elimination methods in the articles with the implementation of each node):

Difficulties encountered

1. PLC documentation

Beta testing of the declared PLC on the MasterSCADA 4D core was indicated by the manufacturer in 2012. Despite such an impressive period of existence of the concept, all that a developer has in 2019 is a programming manual of 28 (!?) pages, on which there is a little less than nothing useful information, moreover, screenshots in the manual from MasterSCADA 3D, which is quite funny with given that the interface has changed.

Also actively supported by three adepts and a sales manager is a forum thread with 20 topics.

2. Architecture PLC modules

This is a separate topic for discussion. Briefly: the PLC communicates with the modules as with Modbus RTU slave devices, which must first be configured by the utility separately by connecting each to a PC via an RS-485 converter.

Smart uncles, of course, probably know how to do this without a converter through a PLC, connecting modules in series to the network and writing the necessary registers, but this comes with experience and a lot of pain.

For a developer who first saw such an architecture, it is not at all user-friendly.
Also, all analog modules like to go into failure for unknown reasons, taking the entire RS-485 network into Terra Incognita, but I also want to talk about this separately, a whole epic, of course. The problem, by the way, is 10 years old, the manufacturer laughs it off “It must be admitted that we did not succeed with the templates”, however, this is the only interface for communicating with modules, and people, quite seriously, have been writing their Modbus RTU implementations for a long time.

Meanwhile, chamomile tea was running out... The sun went down

3. IDE MasterSCADA

We won’t talk about graphical tools, I didn’t test much, but I’ll say right away that I didn’t like it.

We are talking about the implementation of data exchange and the languages ​​​​of the IEC standard:

The physical inputs and outputs of the controller are not global variables and cannot be accessed from any part of the program by writing an alias, for example "DI1". It should be dragged into each program with handles, a local variable is formed there, which inherits or transfers a value. Those. the very essence of the PLC, in my vision, is a little lost: the device should simplify the programming of the logic of the operation of physical channels to the level "If the input DI1 is triggered - turn on the output DO1"and it looks like this "Input DI1 - Variable LI1 - Variable LO1 - Output DO1", also due to ignorance of this IDE principle, you can catch a delightful warning “Boolean-Boolean conversion is impossible” (most likely, one of them is a pointer, but I present it in the editorial of the creators, it’s more harmonious).

The libraries of the ST, FBD, SFC languages ​​are quite voluminous and there is a choice for the convenience of programming, however, these components are not functions, but classes, within which methods are hardwired, and secondly, most do not have help describing the functionality and data types. Persistence led me to the CodeSys core libraries, where all these functions were taken from, their help helped.

4. Exchange with SP307 panel

Quite an interesting event for those who have nowhere to spend a couple of days.

Standard GUI testing (HMI or SCADA) for me is to do 6 trials:

1. Reading a Discrete Signal
2. Discrete signal recording
3. Reading an integer value
4. Write an integer value
5. Reading a real value
6. Writing a Real Value

Accordingly, I draw 6 primitive components on the screen and check each one in order
The exchange is exactly the same as with the modules, but from a separate RS-232/485 PLC port, and, it seems, more stable. Since the HMI is a slave, I wrote to it on a change, and read it with a polling of 500ms, so as not to miss the operator's actions.

The first 4 points were performed perfectly, but 5 and 6 caused problems.

We send data of the Single Float type, display them on the screen and see that the data is not the same, although all the output settings (Float, dimension 1 register, etc.) are correct. It would not be true to say that the precedent is not described in the documentation, however, try to find in which and where, it's funny from the outside.

After a hysterical enumeration of all the settings regarding the data itself and its sending, we write to technical support, the answer is on average 5-6 calendar days, we work according to the standard technical support script "Check that the power is on - check the software version - please wait another week - Let's go figure it out ourselves".

By the way, I decided to install one tick in an absolutely inadequate place with an absolutely inadequate signature.

To screen functionality the input of the analog signal of the “Slider” format is not included, you can only enter numbers in the text field. It's simply amazing, either we write the "±" buttons and the script ourselves, or we enter a number from the keyboard, we forget about the soft control of some kind of drive.

I will not overload the article too much, so I will describe the problems with the top level in part 2.

In summary, I want to note that I had enough freedom and a lot of time to solve these problems, which at first glance seem ridiculous, but cause a lot of pain to the victim. In conditions of limited time, it is critical to face such problems.

PS: All theses stated here are subjective, and are only an attempt to warn the unprepared, and not discriminate against manufacturers, please consider this article from this point of view.

The second part is here: click

Source: habr.com