February 12, 2014 by Jeremy Pollard
I have often wondered, “What’s the big deal about safety? There can’t be that much to it!” In fact, I’ve actually said those words to Kevin Pauley, the Canadian manager for Pilz Automation and Safety, whom I have known forever. And that’s when he educates me.
Pilz is a unique company whose only focus is on safety. But of course you need software to develop, monitor and document your safety strategy. Their product offerings go from zero to 60. This column looks at their 30 mph solution.
Version 9.4 of Pilz’s PNOZmulti configurator is full of new things. I have used the previous versions, but stopped at early 6.x. So, going into this, I wondered what was different and how much more mature the platform had become.
The Multi is the hardware platform that interfaces with all things safety. All other products interface with this device, and the configurator software does the things you need to do to program the strategy.
I say strategy because it is not a program as such. It is a protective approach, which is different than a PLC-type control program.
The configurator install went well on a 64-bit Windows 7 platform. Since I had previous projects, I first brought an existing strategy into the editor. As long as you don’t use any new devices or components, the resulting program(s) are backwards compatible. It is fast, which is good, and the fact that it is very picture-oriented allows you to see exactly what the canvas looks like.
Because Pilz deals in various devices, such as foot switches, mats, light curtains and the like, the software supports all of them pictorially.
The main canvas is a segregated template where placeholders are deposited on the screen. Each icon has wired placeholders to create the strategy to control the ‘K1/K2’ main power contactors, which provide main power to the process so it can be stopped when it needs to be.
Documentation is so vital, and the only way you can get to the full description is to put the mouse over the icon. Toggling between European and American views yields no difference in the text.
You begin by creating a narrative of how you want the safety system to operate. Once that is done, the rest becomes seemingly easy.
I found the software very responsive both online and offline. I recommend starting with the end result first, by placing the K1/K2 output on the canvas first. Depending on how many devices you have, you can create sheets and use source connection points to navigate the logic to various sheets. These connection points form the entry to the final template. Once you define the outside devices, such as e-stops and gate switches, they are placed on a separate canvas with a connection point to the final sheets.
The real benefit of the software is the ability to see the strategy due to its graphical nature.
When you leave out a link, the software tells you. You cannot download code without it passing a battery of tests. The online monitoring is very intuitive, and someone with basic logic training should have no trouble following the path.
Each icon represents a device, such as an e-stop, by graphics, including each icon’s configuration. If the block’s reset is manual vs. automatic, the graphics are altered.
Knowing these little details can help.
The ability to produce macros to populate the canvas with an automatic flair is interesting, but the project would have to be big to use this feature. Spreadsheets for import/export are supported.
There are a few annoying roadblocks, such as looping back behind the elements on the canvas. If you try and traverse the logic flow, you will be denied. It seems that Pilz logic solving is similar to Modicon’s cell-based execution.
The menu sidebars are very helpful, and carry on the consistent graphical nature of the platform. They have done a good job of defining the safety devices used in industry to be communicative to the user monitoring the system. The printouts are self-documenting, if you will.
I have always liked the ability of Pilz to keep it simple. Safety systems are there to just work, and Pilz does a great job of that. You can access the connected state of the devices by Ethernet using ModbusTCP. It holds the current program on a chip card — which means no batteries — and protects us from ourselves by not being able to remotely download.
The PNOZmulti hardware platform is very cool, and the configuration software is easy to use. Let me know what you think!