Michael Lloyd

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About Michael Lloyd

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    Expert
  • Birthday 06/01/58

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  • Gender Male
  • Location Texas
  • Country United States
  • Interests Photography, Long Range Shooting, Reloading, Fishing, Hunting

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  1. Interview Question

    I agree with the last two posters. I'd rather have a tech with troubleshooting skills than a programmer. If you hired a programmer, and it was me (not looking for a job btw), I'd want to change all of the code you listed to something that would be safe, easy to troubleshoot, and work  EVEN IF WHAT YOU WROTE WOULD WORK (it won't) I've edited a fair share of working programs to make them work "better" when they worked fine as they were and I will probably do that for as long as I work on PLC's. If you want a tech, test for a tech.
  2. You may get quite a few different answers to this question. Personally, I don't like to turn the PLC off unless it's for specific maintenance and even then I don't like to turn it off. The battery has a finite lifespan. If I remember right we change our batteries once every 3 years. I also put a Battery Fault Alarm in each program in case a battery dies before we catch it. If you power the PLC off then the only thing holding the memory up is the battery. I wouldn't trust that.. If it's set up for to do so the PLC can retrieve the latest saved image from the CF card. However, if an edit is made to the program and it isn't backed up to the CF card it will load the old version over the new program IF it's set up to do that. There are various options for when and how the backup is loaded. I stopped using the CF card since the process of backing up required a system shutdown. If the PLC "loses it's mind" a tech has to either remote in or go to the site and download the program to the PLC.
  3. I think I would use a Red Lion DSPGT <--- might not be the correct model. They have a bare bones DSP that doesn't have some of the stuff that the "deluxe" model has. The Red Lion "talks" a lot of different protocols with ease
  4. Find password from .mer or .apa

    It's been a long time since i've programmed  PV plus but if you have the APA file can't you just edit the password to be nothing and compile / upload that?
  5. Bit Shift Left BSL

    Lets say you have a 16 bit integer 12345. The bit pattern for it is 0011 1000 0011 1001. If you BSL 3 times everything shifts to the left 3 places, 0's fill in the rightmost values. 0011 1000 0011 1001 becomes 1100 0001 1100 1000 (hopefully I got that right, it's been a while since I've used BSL)   
  6. COP instruction conversion

    Why not use the COP in CLX?  It's been awhile but that looks like indirect addressing
  7. GPS time synchronisation with AB PLC

    You can log on with your laptop and synchronize it that way
  8. Preferred HMI with RSLogix 5000

    ClearSCADA would be too expensive for you then We don't use many alias tags. I map IO to tags into a tag created from a UDT. The UDT also has two strings for the HMI. Tag and Description. Like so: P1000.RunStat := Local:9:0.0; <-- not the exact format but I use a spreadsheet to build the map file so I really only need to know Rack, Slot, Tag, and Description
  9. Preferred HMI with RSLogix 5000

    Gotta agree with the Red Lion and the way it integrates with CLX. We went client / server so the HMI lives in one place and looks the same everywhere. For machine (in my case, pump, expander, compressor, etc) dependent HMI's the Red Lion works really well.
  10. Preferred HMI with RSLogix 5000

    We used to use the big Panelviews but the then client, now employer, had moved to ClearSCADA so we switched to a Nematron Panel PC running a ClearSCADA client and talking to a ClearSCADA server running Kepware. At the time the SCADA dept was very small and resources were few. One guy was particularly good with ClearSCADA programming. He and I teamed up, I tailored my UDT's to meet his needs in ClearSCADA, and he wrote scripts and created mimics that made the integration between the two systems almost seamless. We use the same tag structure (UDT's to the rescue) and I wrote the programs (52 stations, one with 12 pumps, (5) 250hp, (7) 1500 HP) and he did most of the ClearSCADA development. Eventually I had to learn the HMI said and thanks to his hard work it was very easy. We had the system down so well that we could do a decent sized station in a couple of days. That's PLC and graphics. When I FAT'd the panels, the graphics were done and waiting to he linked. I would use a cell modem to link to the server, pull the PLC database into ClearSCADA, install ClearSCADA on the HMI, have an IT guy remote in an add the license, turn on the comm in Kepware, and bingo... all done. Needless to say, I'm a fan of ClearSCADA / Kepware for AB CLX PLC's
  11. visual basic to rslogix

    Sure isn't :)  
  12. Tisoft analog alarm programming

    The analog alarm block in TiSoft (I actually use Workshop but TiSoft works) is a real handy block. Give it a Vflag address and then use Vx.x bit to trip a C bit. I map every single analog into the alarm blocks. I map them consecutively. Ie Alarm 0 is the first AI point on the card, Alarm 15 is the 1st alarm point on the second card. etc If you use 8 point cards the numbering changes. The alarm blocks may start with 1. It's been awhile. I even map the unused analogs to alarm blocks so future added analogs are easy to implement. The true value of the block is that all of the features of the alarm are in one place. Scaling, setpoint, scan time, etc. So HMI programming becomes easy (easier) and more structured and troubleshooting an alarm or shutdown is very easy. Disabling an alarm or shutdown is easier to program. There are lots of good reasons to learn to use the alarm block in the TI. I make it a habit to latch shutdowns (so if something blips i can see what shuts something down).  I liked the alarm block so much that I made one for Siemens S7 and the Control Logix PLC when we stopped using the TI (beast of a PLC though) and moved on the S7 and CLX.  
  13. OTL with no OTU

    Lol... posted as I was typing. 
  14. OTL with no OTU

    ^^ most likely answer but I think, but haven't verified, that an OTE turned off will unlatch an output too but I can't think of a good way to use it off the top of my head  
  15. SLC500 - resetting the time

    Might be a script in PV