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av8or1

Deciding on a controller

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Hi- How are you? I am looking for a little guidance regarding the selection of a micro controller for a home project. I did a search on this forum but didn't come up with what I was looking for, so I thought I would post my question here. Hope it is ok. My usage of the controller won't involve the governing of anything vital or anything that could harm someone (like a saw, etc.), just lights mostly and possibly one small fan. With that in mind I had tenatively selected the AB Micrologix 1000. However I cannot decide on which model to get. I'm looking at the 1761-L32AWA or 1761-L32BWB ... the inputs will consist of sensors (proximity sensors, photo-reflective sensors) and the outputs will provide the control signals (switching) of lights. I'm guessing that the BWB is the way to go in this case, but I am a complete newbie with this stuff. I am a pure software guy, so learning the ladder logix stuff was relatively easy, but getting that to work with the real-world stuff isn't something that I deal with at all really. So any input would be greatly appreciated. Thank you, Jerry

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Given your limited hardware experience I want to be sure of one thing. If the fans and lights you are cotnrolling are 120 VAC you will not want to be bringing that 120 VAC into your PLC. You'll want your plc to switch "power relays" which send the working power to the lights or fan. Hope this makes sense. That said your choice of AWA or BWB will depend a lot on the "power relays". Given the latest NFPA 70E safety guidelines I'd recommend using the BWB and wire everthing but the final working power to the lights and fans at 24 VDC.

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You might also consider the MicroLogix 800 line. I'll echo Bob and suggest 24VDC for controlling relays that control the actual loads.

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Bob & Joe, Ok thank you for the feedback. Even though I am a software type, thankfully I know what relays are and what the phrase power relays means so at least I'm not that far out in the woods. As I mentioned, I was guessing that the BWB and 24 VAC was the way to go, but just not sure and so I thought I'd ask. I'd like to match my design to the general tenor that the expert folk such as y'all would do yourselves if it was your project. And I agree with your general caution of safety completely, although I don't know what the NFPA 70E means (suppose I'll have to Google it tonight if I get time). So is this style of controlling real-world-equipment via power relays that are connected to your PLC the general preferred design in the industry currently for this type of application? Is there anything special that you need to do with the sensor inputs? My guess is 'no'. Bob, what is the diff with the MicroLogix 800 line? Then I came across the notion of where to mount the PLC. This application will control lights that are in the garage. So I was planning on doing the wiring through the walls and ceiling as appropriate and then mounting the PLC horizontally (along with the relays) on a fabricated mounting that is located in the attic. I do have attic fans and ridge vents, but this is TEXAS and so it will get hot in the summer. I checked the operating temperature range for the AB MicroLogix 1000 and I believe that with a horizontal mount I should be ok. It might sound daff, but the fan that I was considering would actually be a fan that would turn on to help keep the PLC cool as needed. I dunno, such a design seems ok on one hand but yet not so much on the other. Any thoughts - am I doing something that sounds crazy to your expert eyes? Finally, I tried to install the RSLogix Starter Lite application the other night that I downloaded from the AB website. But the install failed, citing that Windows XP Home Edition isn't supported. Is this really the case? Thanks much! Jerry

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Joe- Disregard the question about the Micro800. I did a Google search and read about them last night. Thanks! Jerry

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Generally speaking any voltage below 50 volts is non hazardous and is much safer to work with/around. NFPA 70E covers electrical safety in the workplace, and governs safe practices for shock, arc flash and other situations, going with 24VDC makes life much safer and easier.

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UPDATE: After doing more research regarding AB controllers, I learned a fair amount and then decided that the best course of action would be to call the local AB representative and speak with them about my needs. The primary contact is more of a sales type individual, but he put me in touch with one of their techies who was able to answer most all of my questions. I haven't asked him yet about why I couldn't install RSLogix 500 on my PC running XP Home Edition. I'll do that the next time we speak. Anyway after a couple of conversations with him, I decided that the Micrologix 1000 probably wouldn't meet my needs (I/O) and so we began discussing the Micro800 line. The 830 and 850 are overkill for my project but the 810 seemed lacking upon first blush. He mentioned that he thought that the 810 might be capable of expansion I/O, but that it might be another year before that was available. He mentioned further that the 830s are shipping in limited quantities and the 850s aren't out yet. Or at least he hadn't seen any. So we left it with the notion that the 810 was going to be my best option, provided that it could be expanded to handle 15 ins and 15 outs. I'll let y'all know what we come up with. Thanks, Jerry

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I know there are some technical reasons, but the practical result is the Rockwell Software doesn't test or support XP Home Edition, only XP Professional. RSLogix 500 is one of the products that actively checks to be sure it's being installed on a supported OS. I haven't held a Micro 810 in my hands yet to see if there's an expansion I/O bus, and I'd be surprised if there was. One is not apparent in the photographs I've seen. I just sent an order for nine of them to my distributor. Last time I ordered a batch of Micro 800's they went on stop order that very afternoon, so I'm hoping that the supply chain and the technical issues have been ironed out ! Edited by Ken Roach

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Hi Jerry, Just pick up a used Micrologix 1400. They run sometimes for less than $500! (shop around) It has a built in web server, plenty of on-board I/O, expandable I/O modules (if you need in the future), uses RSLogix 500 (now compatible with Windows 7), etc! PLUS!! you can connect to it using Ethernet (instead of serial), you can VPN to it (if you add it to you Home's LAN and set up your router ports). You can even build an HMI on your Home PC (I would go with Ignition software - Free!) Trust me, this is the best option. I love working with ML 1400s in small stand alone projects. Hope this Helps! Edited by Digita7Voic3

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i also prefer the ML1400 for small projects, but for this, I would take a look at the ML1100, cheaper and still expandable. Ken

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All- Sorry for the delay in keeping this thread going; came home to a surprise in October and have been subsequently going through a divorce. Fun stuff. Anyway, the holiday break is here and so I decided to use the now-free time to finish off this little project. Based on the information I learned via this forum as well as additional research coupled with a budget in mind (that I've already blown really, but I digress), I ended up going with an AB 1761-L32BWB. I made that decision based largely on the input I read in these forums regarding the general notion of using 24V DC when working with PLCs due to safety concerns. This is going to be installed in my house and I don't want this to look like amature hour, so it seemed like good counsel to follow the general notion that the industry uses. Thus I'll use 24V DC to control/switch and power relays to actually power the lights (120V AC, 60W). I will put all of this in an electrical enclosure and plan on including a fan for those hot summer days in TEXAS. Gotta look into the thermo stuff next, but one thing at a time. Anyway, to deal with the software issue, I took out a spare PC that I had because it came with an XP Pro disk (I had forgotten about that) and installed XP Pro on that spare PC. So now I will just do the PLC programming on it as necessary. Downloaded the RS Logix Starter Lite and RS Linux components today. Will begin programming tomorrow night. Have ordered the PLC, a programming cable, a 24V power supply (transformer), a bank of power relays and an enclosure. Will visit the local AB rep tomorrow to pick up the sensors. Going with photoelectric polarized diffused and so I will need to get some reflector tape as well; not sure where I can pick that up, gotta investigate that too. Then I will need the cables, the fuse stuff and the internal wiring. And some bracketry. Should be good to go after that. It'll be a pretty cool winter break project. I will post when I have it up and going. 'Plan on doing a video for YouTube of the final product, just for funzzies. Thanks again for everyone's input, Jerry

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All- Quick update: I have successfully written my first PLC program for this home project and was able to verify its correct operation with the help of the emulator (from the AB website). Thus far I have the line power cable, controller, communications cable, DIN railing, terminal blocks, end barriers, end retainers, fuse holders, fuses, sensors, chordsets and the power relays (plus their bases). Still waiting on the 24VDC transformer/power supply, the enclosure, the final power wiring, internal wiring and some miscellaneous hardware. I had hoped to close it out over the break, but shipping of components has been slow despite relatively early purchases. So maybe not until next week. Will post again when finished. Anyway, thanks again. Jerry

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All- Another update (and I hope it is ok to continue posting here, I realize that my PLC project is my first and is relatively trivial to those more versed - but to me it is still exciting!): I received the enclosure and have been working to get everything laid-out and mounted in what seemed like an organized fashion. I have downloaded my program to the PLC and using a jumper wire, I verified its functionality to be correct. I still need to wire the inputs from the sensors and the enclosure ground. Plus the fans, almost forgot about the fans (shouldn't be a big deal, it will be external to the PLC stuff). Attaching a picture of the progress to-date. Will post a link to the video of the final result when I get that completed and online. Thanks again for the input; my design inside the enclosure ultimately sprung from the advice received on this forum. I'm following PLC established convention, or at least trying to! Jerry

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Y'all- Got the panel mounted in the attic tonight. Had to custom fabricate a support structure in order to mount the box over a wall so that there would be support all the way to the concrete below. That'll mean a little extra wiring, but oh well. Just one more cordset's worth. Thanks, Jerry

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Not bad especially for a first build. I might suggest the following to avoid headaches in the future. And keep in mind this suggestion for home use is a preference, in the workplace there will most likely be regulatory standards which govern the build of panels. I'd use Black or Red for 120 VAC Hot ; WHite for 120 VAC Neutral ; Green for Ground ; Blue for 24 VDC Positive and White with Blue Tracer for 24 VDC Negative. It would make the 24 and 120 feeds to your relay panel look so much neater. The attic mount is just sweet. You know you've done well if you can replace or add a drop cord on the 4th of July and not cuss about laack of space in the box. LOL

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Hi Bob, Ok thank you for the feedback. I will use that suggestion during the next build. I bought my wiring at a local box store, not sure if they'd have the white with blue there, but maybe. 'Could always find it online if need be. Working now to get the sensors online. It ended up being two cordsets worth and I hope I have enough at that, now that I think about it. We'll see. It's taking longer because I am choosing to solder, tape and then heat shrink each union rather than use wire caps. Had I known what I know now (which means that if I had planned the panel mount placement better) I would have just bought the longer cordsets and been done with it. But I thought that I could get away with mounting it near the receptacle, which is over a roof joist and the weight of the panel was simply more than I had thought it would be. And I didn't feel comfortable with pressing ahead with the plan anyway. It's my house and I'd rather over-engineer than do the opposite. Oh well. Keep ya updated. Fun project!

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Enjoy your project. One other thought given this is in the attic. I don't recall if your plc is ethernet capable or not. Either way you may want to bring an ethernet or other programming cable from it to your main occupancy area so as to not have to climb into the attic to tweak it.

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Great idea. Unfortunately this PLC is just a Micrologix 1761-L32BWB, so the only interface with it is the standard serial port, RS-232 type connection. I bought a cable off of Ebay for it, and I suppose that theoretically you could splice a few of those together to get the same result, but I don't know if I'll go that far or not. As I mentioned I had to use an old spare PC that I could install XP Pro onto so that I could run RSLogix/Linx. Point being that I am not using my regular-home-use PC anyway. Though you're correct, it would be a pain to have to carry the box, the monitor and the mouse/keyboard up to the attic. Funny you should mention this however. Like always, designs are often modified or augmented. I thought of a small addition that I would like to make that shouldn't require much time or effort, though it will require adding additional rungs to the ladder logix program to produce the desired result. So over the next couple of days I will likely do just what I mentioned above. Hah! Thanks, Jerry Edited by av8or1

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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!

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You've a few options to remote connect to your micrologix. 1. Install Rockwell's 1761-Net-ENI and use ethernet. [This option will work but at the $hunreds they charge for this it will also be the most expensive} 2. Get a Serial over Ethernet adapter. This way rslinx and rslogix will think you're using serial, but the adapters will ahndle the conversion. This should be a sub $100 approach. Im can't recommend a specific brand, but hopefully some of the gurus who've done this will share their expertise and give you food for thought. 3. Extending the Serial is an option. I would not cut the cable you bought, I'd buy a cable premade with proper gender on the ends to work. And probably a null modem just in case. If you run the extended cable more than 50 feet, be prepared for noise unless you slow the serial down to 14.4K or 9600 potentially. And at 50 foot or greater my perrsonal favorite cable is Black Box Heavy Duty RS232 for Hi Noise Environments. Or something like that from Black Box.com. This is probably your cheapest or mid price option. Depending on distance and cable costs.

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Johnboy -> thank you for the compliment. The panel isn't finished just yet actually, I still have the fans to install to keep everything cool in the heat of the TEXAS summer, plus the aforementioned design augmentation will result in a minor rewiring job to accomodate a new output. Fun stuff though! And if I do another project like this, I will indeed research the ZWave stuff. Thanks for that pointer. Ok sensors. Does anyone out there have much experience with these critters? Specifically, I have an AB photoelectric sensor (polarized retroflecive == 42EF-P2MPB-F4) that is supposed to have a maximum range of 3m or 9.8 ft. From my initial purchase experience in the local AB distributor's office, I learned that you can have these reflective disks or reflective tape. The latter fits my application much better, but when I have the sensor mounted on the ceiling and the reflective tape on the floor, the sensor doesn't find the tape. According to my trusted Stanley tape measure, the distance from the ceiling to the floor is 8' 7" - which should be well within reach of this sensor's maxium range. "Hmmmmm....", thought I. And so I decided to experiment. If I raise the tape up vertically off of the floor and towards the sensor, it will pick it up at about 5 ft or so from the ceiling (approximately). My conclusion after some experimentation is that this is due to the sensor's mode of operation and the size of the strip of reflective tape. I think that at the latter end of the range the emitted beam grows in size such that it exceeds the size of the reflective tape. Thus the tape isn't being "seen". Then as you move the tape closer to the sensor, the beam narrows in diameter and once it reaches the point where the diameter is just small enough to fit entirely on the tape, the reflection is picked up. So the solution would be to increase the size of the tape on the floor. And another thought hit me during my little experiment. Those disks. As I mentioned, I recall the staff showing me the reflective disks. They were indeed circular in shape and of a certain size, though I don't remember now just how large. Perahps the size of a half dollar. Anyway, my thought is that whatever size it was/is, that is the size of the width at the maximum range, or else not far from it. Thoughts on either the proposed solution or the disks? THANKS! Edited by av8or1

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This is probably obvious, but If I am looking at the correct part in the catalog there is a setup and teaching procedure to teach it distance and object. Have you read and done that? http://www.ab.com/en/epub/catalogs/3784140/10676228/4129858/6279458/10702223/tab2.html http://literature.rockwellautomation.com/idc/groups/literature/documents/in/42ef-in004_-en-p.pdf http://literature.rockwellautomation.com/intradoc-cgi/nph-idc_cgi.exe

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Bob, Ok great! Thank you for that information. I like the second option the best and will look into that. Also, in regard to the serial cable: just after I typed the word "splice" and logged out of the forum, I realized that the better option would be to just get the appropriate connectors and lengthen the cord in that manner, just as you suggested in #3. Good call! Jerry Edited by av8or1

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Hi again Bob, Thank you for the continued guidance, I appreciate it! Well no, I haven't done what you mentioned because the particular model of sensor that I purchased (42EF-P2MPB-F4) doesn't appear to be teachable. The folk in the local AB distributor's office confirmed that when I inquired about it during the purchase. Sure enough, in following your links, it shows that my sensor does not have a teachable distance (nor adjustable for that matter), and I don't recall seeing that in the documentation that came with the sensor (I read that sheet of paper carefully prior to attempting to power it up and use it). The sensor that I have is polarized retroflective and according to the AB website the only polarized retroflective sensor that is teachable is cat #42EF-P8KBC-a. That is unless I am missing something from reading the literature, which wouldn't be the first time. I'll keep playing with it and see what I can come up with. Open to any suggestions. Thanks again! Jerry Edited by av8or1

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UPDATE: I spoke with an AB rep today about this issue. The answer seemed kinda vague, so I decided to browse the AB website for more detailed information. In so doing I have learned that different types of AB reflectors have different levels of reflective capability, depending on the type of reflective material and its suitability for use with a photoelectric sensor. They are measured against their standard 3 in diameter reflector (one of those disks I was referring to) which has a 100% relative reflectivity over all applications and sensors. The long story short version is that it would appear that the tape that I have is at the bottom of the totum pole in terms of these types of sensors. So increasing the overall surface area of the tape might not solve the problem when applied in the longer range scenarios. Still, I plan to give it a try tonight, mostly since I already have the tape and can't get with the AB distributor until Monday anyway (they're moving their office). Also because I should try to make this work before spending even more on new sensor disks. Again, the disks would not be ideal in this scenario, not by a long shot. They could and likely would be destroyed easily and I would just need to replace them. And I did look up the maximum beam width for a polarized retroflective sensor. That turned out to be approximately 36 mm at 7.5 ft. At the maximum range distance of 9.8 ft, the beam diameter is reported to decrease to about 28 mm, which is just more than an inch, and the tape I have is 1" x 100", so yes, it would be just wider than the tape is. So hey, I'll give it a try and see what happens. Will make a report here afterwards, with the intention of providing information that might be valuable to others in the future should they seek such data. Thanks! Jerry Edited by av8or1

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