Phil Salkie

I don't think that's quite what he had in mind - Perry, what do you mean when you say "Ignore input 1 while input 2 is high"? Do you mean that for 500 ms after input 1 goes high, all signals from input 2 are ignored? And, similarly, after that, for 500 ms after input 2 goes high, all signals from input 1 are ignored? If so, you're looking at something more like this: MB1 T1 --| |---------------(0.50) MB2 T2 --| |---------------(0.50) I1 MB2 MB1 --| |-+-|/|-+--------( ) | | | T2 | +-| |-+ I2 MB1 MB2 --| |-+-|/|-+--------( ) | | | T1 | +-| |-+ For example - if I1 comes on with I2 off, then MB1 immediately comes on, which prevents I2 from turning MB2 on. However, T1 also starts timing, and after 500 ms, will allow I2 to turn on MB2. At that point, whenever I2 turns on, it will turn on MB2 (which will keep I1 from turning on MB1). Note that if I1 turns on and stays on, then after 500ms I2 turns on, MB2 will come on and MB1 will turn off for the next 500 ms, at which point MB1 will turn on again, and MB2 will turn off. If you were looking more for a circuit which would ignore the _entire time_ I2 was on if it came on within 500 ms of I1 turning on, you'd want something more like this: MB1 T1 --| |---------------(0.50) MB2 T2 --| |---------------(0.50) I1 MB2 MB1 --|P|-+-|/|-+--------(S) | | | T2 | +-| |-+ I1 MB1 --|/|----------------(R) I2 MB1 MB2 --|P|-+-|/|-+--------(S) | | | T1 | +-| |-+ I2 MB2 --|/|----------------(R) Here, if I1 comes on, for the next 500 ms I2 will be ignored, and if I2 stays on after the 500 ms, it will still be ignored. Only if I2 changes from OFF to ON after the 500 ms has elapsed will MB2 come on, disabling MB1.

Hi! I'm Phil Salkie, Lead Engineer for Howman Controls in Edison, NJ, USA ( http://www.howman.com ). We're a small distributor and manufacturer of industrial controls products, and a UL-508A panel shop. Howman has been in business for about 30 years, and I've been here for 25 of them - if you've watched a sporting event on TV, dealt with a large bank, had a wound sewn up, or bought a banana, a gallon of gasoline, or a computer chip, there's a good chance that some of our hardware or software was in the mix somewhere in making that item or service, or getting it delivered safely to you. We've been a Unitronics Distributor since around November 2009, and we've got about 15 projects (mostly based on the V570) in the field now, some with just one controller, some with a dozen - I'm starting to feel like I've learned some things, and that some of what I've learned could be interesting enough to share. Perhaps the first thing I learned was just how powerful the Enhanced Vision's communications functions are. My first project, when we were evaluating Unitronics as a possible replacement for an Idec Open-Net PLC, was to write a communications driver which let the V570 talk over an RS-485 network to an Idec master. I was able to implement a completely functional network slave in a surprisingly small amount of ladder code and an equally surprisingly small amount of my time. Since our development cycles are mind-numbingly short, I was quite impressed by how quickly it came together, and we signed on with Unitronics soon thereafter. In subsequent projects I've written other drivers, and found that some protocols don't happen to fit well with the features in the comms function blocks - but there's always been a way to make it work, and so far it's been pretty straightforward to implement communications to foreign devices. We now regularly install V570s which talk on two networks to two redundant Open-Net masters - something the Open-Net itself can't do. Something that I found fairly quickly after the first discovery was that Unitronics has an extremely responsive support group. We are definitely "power users" here - we tend to push hardware and software right to its limits immediately after figuring out how to turn the stuff on. Our Idec network driver uncovered a problem with an intermediate firmware upgrade, and (unlike any other PLC vendor we'd ever worked with) the folks at Unitronics took the demonstration program we gave them, diagnosed the problem, and issued a firmware upgrade to fix it, all within days. We've asked for features, and found things in VisiLogic that needed work - and while not everything gets done overnight, it has been a pleasant surprise to see how many of the things we've pointed out have been addressed, and how quickly that work has gotten done. I won't drag out the war stories of trying to get some of those Other vendors to fix problems with their products, I'm sure we all have our share of those! One tool which I've found indispensable, and which I'll recommend to you, is AutoHotKey ( http://www.autohotkey.com ). It is a free, open source Windows keyboard/mouse macro editing language and tool set which lets you automate some of the little mind-numbing tasks we encounter. When you want to change the color of fifty little on-screen items, you can just program Control-Shift-O to click on the item you've pointed at, select the color palette, pick the new color, click OK, and close the edit dialog box. A tremendous time saver for any Windows program where you have to do the same thing again and again and again...