johnboy

Hi Jerry, Well I would definitely say that your situation is unique, but should be do-able none-the-less! Maybe a couple of low-tech approaches would work: 1. Depending on how close the Jeep is to the wall, you might could mount a limit switch on a piece of uni-strut with a homemade wand that would activate by the tire. This would be adjustable on the strut for various vechicles. 2. A vacuum switch on a piece of hose so that when the tires ran over it, it would activate the switch. (Similar to the full-service gas stations that would ring a bell when a car drove over the hose.) 3. I believe that there are pressure mats that can be purchased that activate a switch when a forklift or vechicle drives on them, I'm just not sure about the cost. In the meantime, I'll keep working on other solutions. I'll let you know if I come up with any!

Jerry, Your AB Rep was right about the diffuse PE's, usually if you set them up on a light colored target, they have a hard time with a dark colored target and vice-versa! However, Telco has a prox (P/N SPP2903C $100.35, w/ cable P/N 80459A $20.27) that will see out approx 3m and is good at seeing light/dark targets. Take a look at that, and if you don't think it would work, then maybe a Telco (or I prefer Banner) ultra-sonic sensor would work, but then you're looking at $400-$500. Another option would be a see-thru eye which can have a range up to 200 ft or more. With this option though, you would have to set up a transmitter and receiver, probably on the walls. My primary occupation is industrial automation, but I do like to play around with home automation as well. If you tell me how you plan to block or trigger this eye (I'm assuming your car but you said that a motion sensor is too broad), maybe I can come up with another idea as well. Good luck, John

Is your target that will be blocking the Photo-eye at floor level? If it's a few feet off of the floor, perhaps a prox or diffuse type eye might work and you won't need the reflective tape to bounce the signal back to the eye, or you can mount the eye on the wall to detect the target. Of course if the Laser eye is within budget, go with that since the beam will definitely be smaller.

Two suggestions: 1. Perhaps a Photo-eye prox might work in your application. These can be found with a range out to approx. 9ft (Telco or Banner approx $140) and they only need a target such as a car or something to block them. 2. Some type of motion sensor might work for what you are trying to do, but they might be hard to find in 24 V. Another option would be to use a 110 VAC motion sensor that you can probably find at Lowes or Home Depot and wire that back to a relay to trigger an input on the PLC.

Just out of curiosity, what are you attempting to see with the photo-eye, and what do you plan to have the program do when it is blocked or clear?

I'm not sure exactly what your project is about, but it looks like some type of home automation. Since you're a software guy, I would have recommend looking at a ZWave controller (I have been using VERA from MiCasaVerde for the last few years). Anyway, the devices are very reliable, have come down quite a bit in price, and there are several relay output devices for fans, lights, etc. I don't know how much you have tied up with the Micrologix, but you might have come out a little cheaper. For a first time project, you did a nice job on the J-box!

Don't know if you have found a solution, but we use Excel 2010 and I opened it up yesterday and put in a couple of DDE links from PLC5 and CompactLogix, and was able to read both. You might try manually updating some of your links to see if that works!

Can you see your processor in RSWHO?

Try this: Data Source: OPC Server Name: USA (enabled) Server Name: RSLinx OPC Server Server Type: In-Process Access Path: USA

You might also want to check the properties for all of the folders in your Project to make sure that they are not set to "Read Only". This could happen if the project was backed up and/or reloaded onto a disk.