Frequently Asked Questions

These are answers to most common questions, and please contact us with any other questions you may have..

 

How is the PLC code generated ?

Most high-level automation platforms compile to source code for the PLC, but in Accord a powerful PLC Library implements the model using the data generated in the model. In this way there is no code generation, once the Library is installed in the PLC then all the devices and programs and other items in the model will be automatically generated.

This is fare more efficient than compilation, especially for small changes, or delta, or Partial downloads, as the PLC operation does not have to be stopped – in Accord the PLC accepts the new changes while the process is being controlled by the PLC without any interruption.

The PLC Library is downloaded from the usual PLC Editor and so other code can be written in the PLC using this Editor.

 

How can the PLC data addresses be found or monitored?

Accord Server arranges the PLC addresses during PLC downloads for full new systems and modifications (Partial Downloads).  Device Report (Complete) in Tools section of Accord Server contains a list of all addresses for all objects in the PLC. The addresses may be copied or exported using the Export Tag List tool.  

Can we use Accord with other HMI, Scada or MES systems?

Yes, of course. All the PLC addresses are available so can used as tags in other editors. The .csv file can be uploaded directly to InTouch or modified in Excel for other applications. Accord does not change existing addresses during modification downloads so existing tags on Screens or in queries will not be affected.

Can we monitor states and values within the PLC ?

There is a PLC Register status in Tool section of Accord Server. This allows PLC values and states to be monitored, and they are selected using the Model item names, so the PLC addresses are not needed. Of course once you have obtained any addresses here or from Device Report you can also monitor in your PLC editor.

What PLC types can we use and how do we use Accord-PLC ?

There are PLC Libraries for Siemens, Mitsubishi and Schneider type PLC’s. The Libraries are imported into the PLC Project in the PLC Editor, when PLC Hardware is configured usually. PLC Library is in specific blocks to be reserved and Data is generated in specific Data Areas in PLC.

How do we change a Project from one PLC type to another ?

The PLC type is assigned or changed in Accord Builder in the Project Summary as the I/O types and addresses are part of the Model. Builder will automatically assign the I/O points on change of PLC Type but these should be confirmed. The I/O Document Print may be used for this. The changed project may be imported and downloaded to the new PLC. The system will operate in identical manner to original PLC, with new hardware.

How do we change Model from Emulator to a PLC for installation ?

The PLC or Emulator is always selected in Builder as part of the Model. An Emulator profile is available in Server, similar to OPC profiles. So when the Project is to be downloaded to a PLC the PLC type is changed in Builder and the project is them imported and assigned to an OPC profile in Server and downloaded to the PLC. Accord HMI, Controls, Recipe, Batch and Reports will then operate using PLC data without any changes or tagging.

How do we interface with PLC registers ?

Once the import and download has occurred then PLC registers are available. These include Variable registers which may be read and written to by other PLC code. In this way other PLC code can generate values for the Accord system to use.

What is the advantage of using Accord HMI ?

Accord HMI has controls which complement the Server data so the quality methods and time savings continue; the configurable items in Accord HMI have the same standard aspects built in. We think the main advantage though is the central management using the settings in Accord Server which provides a server based set-up for Operator Security and Log-In, Historian and Archiving.

How do you download the Model to the PLC ?

Firstly, the Accord PLC library must be installed using the PLC editor. It can be copied from project to project, like any PLC code. Then the Model is imported into Server and the data is downloaded to the PLC. (that’s it, the control strategy is now in the PLC, ready to control the process or plant).

Partial Downloads;

Changes to the model may be downloaded without affecting the existing running system using a Partial Download.

Is Accord good for S88 type systems ?

Accord is very suitable for S88 type systems. Accord Builder Equipment section is equivalent to Physical Model; instances of Valves, Motors and Instruments, are equivalent to Control Modules. The setup of Programs is equivalent to a Procedural Model; Programs can be considered as Phases, containing Steps and lists of Activations. Accord provides a framework for S88, and is useful for general learning about S88 also.

What about 21CFR Part 11 compliance ?

All actions are logged by Server. There is a User Profile section within Server which allows Users to be set up with permissions for all possible actions in the configured system, e.g. to be allowed to activate a device manually. If users are set up then all the actions of that user are logged to them. Queries performed using Accord modules such as Audit Trail or Accord Reports or the security auditor will list the users who carried out the actions.