Div_by_zero

need advice on constructing a simulation / debug box

6 posts in this topic

I want to make a small simulation / debug box. This box will have a PLC, an additional input card, output card, and an analog I/O card. It will have a touch screen and a way to interface with the outside world. The simplest job it could have is simulating one to say 16 discrete inputs on the panel PLC that I'm testing. The touch screen will allow me to easily label the individual test buttons, as well as give me a ton of other flexibility over physical buttons or switches. Beyond that, an analog I/O card would allow me to simulate continuous level sensors and other such devices and control them from the touch screen (a whole lot cheaper than purchasing several Fluke 705s!) This is all the easy part. Selecting the components and programming the simulator PLC code is cake work. What I'm trying to figure out is how I want to make the wiring connections to the outside world. What kind of terminals / termination points would be the most versatile and what would offer the "cleanest", most organized look and function, and be expandable. I've seen plenty of sim boxes that are a big spaghetti mess on the outside..no fun to deal with. Thoughts / comments / advice welcome. Thanks!

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I suspect your answer will depend a lot on what the devices are that you plan to test with it. No matter what you do on the simulator end you will still have to get the connections to the test device. If they are all similar you have lots of options but if they are all over the map there really isn't a whole lot you can do other than run everything out of the simulator with multi-conductor cables.

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If you are using Omron PLCs and NS screens the simulators work together - there is even a software switch box for your switches. not sure how it all handles analogues though - i never use the simulators - just write my code and go and commission the job.

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I run the panels in the shop first to wring out (hopefully) 95% of the bugs. But this requires simulating inputs, both analog and digital. I'll have to check out the Omron PLCs and NS screens.

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The nicest one I ever seen had banks of toggle switches that were 'NO' and held Closed in the up position but momentary in the down position and wired to Spring terminals which were quick and easy to attach nearly anything to.

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Debugging includes in reverse thinking, such as understanding homicide riddles. Something outlandish happened, and the main strong data is that it truly did happen. So we must think in reverse from the outcome to find the reasons. When we have a full clarification, we'll comprehend what to alter and, along the way, likely find a couple of different things we hadn't anticipated.

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