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Help Topics

FAQ - Frequently Asked Questions.

Q: I can't connect to my I/O.

Does the device support Modbus/TCP? Not all field devices do. Some require other protocols which are not supported by MBLogic. Also check to see that you are using the correct IP address and port number.

Q: I can connect to the Modbus/TCP server (slave) field device with MBProbe, but it keeps disconnecting me.

Check the configuration parameters for your field device. Some field devices have a "idle connection" time-out which will automatically disconnect any connections which are idle for more than a few seconds. Newer versions of MBProbe have an "auto reconnect" option which can help with this.

Q: What industrial protocols are supported?

Not all packages support all verions. Check the documentation for each package for details.

Q: Why don't some features work with Microsoft's Internet Explorer web browser?

Microsoft IE is based on older technology and can only display basic text and image files. It doesn't have the ability to display SVG (Scalable Vector Graphics). SVG is well supported by virtually every other web browser and allows graphics to be embedded directly in the web browser and manipulated dynamically. While there are some external plug-ins which add SVG capability to MS IE, these have limitations and offer no advantages over simply using a web browser that has SVG capabilities. See the section on "HMI" for more details about web browsers.

Q: What is the difference between the MBLogic project and the MBLogic soft logic platform?

MBLogic refers to two things. One is the name of the overall project. Used in this sense, it refers to all the programs together. It also is the name of a particular individual program which combines soft logic, hmi, communications, and management. All programs share common features, with the MBLogic soft logic program combining most of these features together in a single package.

Q: Why is there more than one version of HMIServer?

The four versions of HMIServer provide different communications options. HMIServerMBC has a built-in Modbus/TCP client (master) and is used when you need to communicate with a Modbus/TCP server (slave). HMIServerMBS has a built-in Modbus/TCP server (slave) and is used when you need to communicate with one or more Modbus/TCP clients (masters). HMIServerSBC and HMIServerSBS provide equivalent functionality for the SAIA ETher-SBus protocol. Choose the version you need for your application.

Q: Will the server (slave) version of HMIServer work with more than one client (master) at the same time?

Yes. The server versions (HMIServerMBS and HMIServerSBS) can accept an unlimited number of simultaneous connections. The practical limit is determined by CPU load.

Q: Why are programs sometimes called "packages"?

A "package" is a technical term referring to a collection of software which peforms a particular function. However, you may think of "package" and "program" interchangeably.

Q: Do I need to install all the packages?

Each package is a stand alone application. You only need to install the ones you wish to use.

Q: How do I compile the software?

You don't have to compile it. The Python run-time system will automatically compile each file as required. having to be compiled.

Q: Do I need to install any other software?

You need to have the Python run-time installed, and for MBLogic you need the "Twisted" framework. Information on where to obtain these is located on the "Installation" page.

Q: What is Modbus?

Modbus is the leading open communications protocol used in industry. There are serial versions (Modbus RTU, Modbus ASCII) and Ethernet versions (Modbus/TCP).

Q: What operating systems does MBLogic run on?

Linux and MS Windows. The Linux version will probably work on BSD, but has not been tested. It may also run on Mac OS/X, but it is not tested there.

Q: Is Debian Stable a supported platform?

Due to user demand, the current Debian Stable release will be considered to be a supported platform and will form part of the regular release testing. When Debian releases a new stable version, current support will be transfered to that version. Unless otherwise stated, any features which do not work on Debian Stable can be reported as bugs and will be fixed as such.

Q: What are the software license terms?

GPL (see the license document in each package for details).

Q: Can I do on-line programming with the MBLogic soft logic system?

Yes. This is accomplished using the web management interface. See the documentation for details.

Q: Is MBLogic a real time control system?

MBLogic is what is often referred to as a "soft real-time" system. That is, the user can set a scan rate target and the MBLogic soft logic platform will attempt to meet that target. However, since MBLogic runs on a normal non-real-time operating system, there can be no absolute scheduling guarantees. This is precisely the same principle under which most conventional PLCs operate. Scan rates are by "best effort". However, under normal circumstances deviations from the target scan rate are small.

Q: Where do I get MBLogic?

Click on the "SourceForge" logo at the top of the page and you will be taken to the download page. Also, see this page for more detailed instructions on how to download the software.