Michael Lloyd

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About Michael Lloyd

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  • 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. CLX Message to SLC error...

    I'll have to pull up both programs when I'm at work to see how I resolved this issue. The cell modem (either or both ends) issue I had went away when I port forwarded the PLC IP to port 2222. This post was a different problem than the cell modem and I don't recall if it was resolved and how it was resolved if so.
  2. SLC 5/04 Output Issues

    It would be easier to help if we could see the ladder logic Although your test method should work try using a button And last, are you sure that you aren’t trying to control an output from more than one rung. Ie one rung turns it on but somewhere else it’s being turned off. It happens more often than you would think. Some of us have even made that mistake more than once. It’s really fun when you do it in big program that uses multiple languages. :) Troubleshooting is half the fun i never say that when I’m troubleshooting     
  3. Siemens S5 to Rockwell Conversion

    Cryptic machine code language, aka STL,  is what you program the S5 with. It'll do some ladder but what you see in the OP's most is what you get when you dive into the land of the S5. I actually like them but kind of like I liked a really annoying girlfriend once... Fun to play with but not a keeper :o)
  4. Copy INT into second half of a DINT

    There is a command for that in CLX but you didn't mention which PLC you are using. BTD - Bit Field Distribute Page 384 http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1756-rm003_-en-p.pdf
  5. Micrologix with 2 ethernet

    We have a few 1761-NET-ENI's on intracoastal platforms in the GOM. I'm glad they stopped making them   The port server to serial port idea is pretty good. If you don't have the RSLogix 5000 software the price differential is a lot higher than twice.
  6. Subroutine

    I completely agree but I also like to look over other peoples programs and see how they did "things". And of course sometimes I scratch my head and wonder why they did "things" :)
  7. Read Modbus holding registers with RSLogix?

    I'd use a Red Lion DSPGT and write the Modbus registers to / from PLC tags. Cheap and easy plus you can talk to numerous Modbus devices
  8. Help: Basic Program Question

    If you don't put a one shot between the button and counter the switch contacts will "bounce" and you'll get a burst of counts.
  9. Etherhet problem compactlogix 1769-L32E

    Make sure your computer and PLC are using the same IP address and Subnet Mask. Ie- If the PLC IP is 10.10.10.XXX and subnet mask is 255.255.xxx.xxx then the PC IP address had to be in the range of 10.10.10.XXX and subnet mask is 255.255.xxx.xxx I usually forget to change my computer IP to match the PLC range a few times a year. Other than that I've never had a problem with BOOTP
  10. Help: Basic Program Question

    Latch / Unlatch is the key to your problem. Counter done and output not on, latch. Counter done and output on, Unlatch. Use the ONS in front of the latch unlatch.
  11. Comms Monitoring of SCADA

    Nope, not silly at all. There is literally a tag called Heartbeat in the PLC and the script turns it on (and then "lets go so it's not latched in the HMI software). I read the elapsed time and some other stuff but the time value can't be read if there is no comm. Our graphics turn "magenta" if the comm status from the driver is bad. I'm kind of handicapped right now. I left my laptop in New Mexico when I came home to gather up the family because of the storm. Otherwise I'd be able to tell you what the value is in Kepware. Somewhere in the driver there is a tag for stale comm.
  12. Comms Monitoring of SCADA

    There are lot of ways to do this. We use a "heartbeat" script in the SCADA software for the PLC side of things. Basically it turns a bit on every time it's run. We run it every 30 to 45s. We shut our remote stations down if comm fails for longer than 600s. For the HMI side we use the Comm fail detection parameters that are built into the driver. In our case we use Kepware for most comm services. There is a health status bit (don't think that's what they call it but I can't check the HMI right now) PLC logic looks like this:  

    If you have an IT group that is responsible for your facility network I would get them involved. They can give you a pool of addresses for the control network that are excluded from the DHCP pool. I'm assuming that your network is behind a router and properly secured from intruders.
  14. 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.
  15. 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.