DeviceLogix and Pico

Anybody is using DeviceLogix functionality with new Distributed I/Os from Rockwell ? Curious to know about the applications where it can be used .Also just wondering for which applications can I use the samll controller-PICO.

IKnowSomePLC

I've proofed out a couple of applications, but as I'm a salesman I don't get to see them in action.

One was the 100-DSA starter auxilary, where they were programmed to turn on an electric linear actuator to open a damper and confirm that it was completely open via a limit switch before they would allow the starter to engage (which drove a powerful fan). They'd do this even if the DeviceNet was offline, because the user put a separate 24 VDC power supply in each bucket.

Another was the CompactBlock I/O, where a customer needed a "medium-speed" counter to position a chain where the pickup was a prox switch on a sprocket. An HSCE card is overkill, and the PLC-5 couldn't keep up with more than about 50 pulses per second. The CompactBlock proved to be able to accurately count a 1 millisecond square wave.... 500 Hz.

I delved a little into the DeviceLogix object model so I know how to dynamically send preset values to timers and counters via DeviceNet explicit messaging, a feature A-B will tell you isn't there. I think DeviceLogix needs to have some limit and comparison functions before it will be more useful... but it's pretty nifty as is. I've thought of a handful of ways it could have improved machines I used to build, mostly by replacing high speed counter modules and allowing crude positioning of screws and chains.

I know the Metro buses here in town run DeviceLogix headlights... a 10 ampere block I/O module strobes the headlights at a 50% duty cycle for daytime use, then full on at night.

Ken,

Good Applications for DeviceLogix. I am just curious to know , how it can work as a counter module in crude positioning of screws and chains.. I know that DeviceLogix device's input-sense to output-actuate time is as less as 2 ms ( for a typical program with 48 function blocks) and hence it can count high frequency inputs. Frankly , I am not familiar with using counters for screw positioning.. Can anybody explain more please ??

Also appreciate some applications where PICO can be best sold.. Is it only for domestic or building automation applications??

[okay, it's a long way 'round to DeviceLogix here, but bear with me]

A common application in my old business that required rough positioning was the outfeed rolls of a strandboard stacker. They're daisy-chained together with double-sprockets, and driven by a hydraulic motor. Different-width stacks of strandboard were moved over the rolls and centered on a pair of chains that transported them down the line.

The only control equipment I had to position these stacks of strandboard was a limit switch, a simple hydraulic valve, and a timer in a heavily loaded PLC-5/40. You had to run a timer after the stack had run off of the limit switch, and adjust the timer preset to center different widths of strandboard. The wild variables were the temperature of the hydraulic oil, and whether or not other high-demand devices were running at the same time and reducing the available pressure. Position didn't have to be too precise, but it had to be within a couple of inches so the stacks of board made it through the paint and stencil machines.

What I would have loved to have was a DeviceLogix-enabled I/O block like the 100-DSA running the output valve. I could run a DC proximity switch to count teeth on the drive sprocket and stop the valve at a precise position instead of a dead-reckoning guess. With a handful of timers selected by Network Inputs, I wouldn't even need to send a modified preset to the block. Doing this with the PLC-5 wouldn't be cost-effective because I'd need long runs of DC wiring to the control cabinet, and either interrupt routines or high-speed counter modules.

The story was similar with screw-positioned hold-down wheels and stacker walls. All you needed was the ability to count about 200 Hz pulses off a sprocket and you could do some quick and dirty positioning that was otherwise done by hand or an overkill servo system.

The Pico controller I don't have much experience with; we actually sell it out of the Industrial Control business instead of Automation Systems where I work.