My last column dealt with Rockwell Automation’s Connected Components Workbench (CCW). But there is much more to say, so this is Part 2 of my review.
The software is free and designed to work with inexpensive hardware platforms. It is also designed to be a global product by supporting IEC-61131 nomenclature. I contacted Rockwell Automation about some communication issues I was having with the software, and I was warned that the CCW is different, and that users expect an RSLogix-type integrated development environment — but they won’t find that here.
IEC-61131 programs are created using POU (program organizational units), data types, etc., as indicated in my previous column. From a development point of view, the engineering mind will create programs and functions as needed. But the online maintenance activities are where we want to look since the core troubleshooting techniques of old still apply here, and there are many new things to consider.
Remember that the tool most employed is a laptop with maybe a 15-inch screen. When the CCW is installed, RSLinx, Rockwell’s communication driver application, is installed as well. The supported devices can communicate via Ethernet/IP or serial USB. The funky part about the USB driver (USB CIPHelper) is that it is a real-time driver install. RSLinx must be running when the device is plugged in so the USB driver can be loaded. Note that unlike previous RSLinx installs, it doesn’t seem to default to run as a service. Go to the RSLinx launch panel to select “always run as a service” to be sure that the application is always running.
The other gotcha is that the proper electronic data systems (EDS) files need to be present, installed and registered. These files are embedded in the devices like a printer driver, but they may need to be embedded manually if the installation process didn’t do it. Be aware that the platform uses a compiled program format, which means no online program changes can occur.
I decided to use a traffic controller template to download. I am running the CCW in a virtual machine and found the transfer and interaction slow. I suspect that a six-year-old laptop might not provide the power maintenance guys need.
The tabbed interface will work well for troubleshooting. Realizing that the devices are for small automation projects, there still needs to be an intuitive interface and usability for that 3 am call.
One of the biggest changes from the ladder logic editors we have used for 20 years is the variables, such as timer presets. They are not changeable from the editor directly. And since the data types and variable naming conventions are different, standard procedures do not apply.
Take the timer block in the graphic, for example. PT is the preset time, and ET is the elapsed time. You have to employ the variable monitor window to monitor and change values. While it provides a window into the process, it is a modal window. Once it is displayed, you can’t go anywhere else, which I see being frustrating unless you are experienced.
Another possible gotcha is that the timer preset could be set as a variable name. The value for that variable can be set using a structured text routine, which may not be intuitive to the user. While an IEC feature, it could lead to unnecessary frustration as well.
The online display is unnerving at first since the instructions themselves only change colour to represent their logical state, which is a diversion from typical ladder logic editors. And it seems there isn’t automatic scaling of windows to decrease the size of the objects in that window. Remember that 15-inch screen?
A typical maintenance procedure would be to spark up the laptop and connect to a processor to troubleshoot. One of the benefits of the IEC model is that all information is stored in the processor itself, so you can connect directly without having a copy of the program anywhere.
Go to Discover, browse connections and select the device. Assuming there is no password, you can connect, upload and have the program with documentation displayed. Then “Build” and “Start Debugging.”
There is no argument that the CCW program is fancy, icon-driven, IEC-like and “pretty,” but it lacks a level of intuitiveness that I was a bit taken aback by. It seems that all events are user-driven. The Rockwell rep I spoke with said that many are lost when they first use the product. But once they are shown how to navigate through it, they are okay with it. And therein lies the rub.
I recommend downloading the CCW and getting up to speed on the product as well as the IEC platform before putting it into play. It gives new meaning to the phrase, “Now that’s different!”
This column originally appeared in the May 2014 issue of Manufacturing AUTOMATION.