Joe E.

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  1. Based on this: You're looking at physical inputs and outputs.  Is a physical start button wired to the PLC?    The PLC reads inputs and reads/writes outputs.  Your HMI can only affect what the PLC can affect, so it can also read inputs and read/write outputs.  If you tie your HMI's "START" button to, it will ONLY be able to SHOW the status, not write it, because the status of the physical input will always overwrite it. If you don't have a physical start button and you want start/stop control to be from the PLC, then you just create tags in the PLC for those functions and have the HMI look at those tags.
  2. Connection between two PLCs

    The way I read it is they want the 2 PLCs to exchange information.  I would think that this is doable using MSG instructions, but I've never done it so can't say for sure.  It will likely depend on how much information they need to exchange and how quickly.  And how far apart the PLCs are from each other.   Hmmm...I just searched the AB knowledgebase and found this article (access level: TechConnect): Yes, you can connect the 2 PLCs together directly serial port to serial port if they're less than 15 meters apart (that's 15 meters of cable, not just linear distance).  To go farther apart, you will need a 1761-NET-AIC connected to each PLC's serial port.  The NET-AIC's are then connected together by their port 2 (RS485 network).  The PLCs will use the DF1 Full Duplex protocol. If you can use DH-485 instead of DF1, you can use 2 1763-NC01 modules (one per PLC). The article refers to this manual for more information on the MSG instruction: ETA: The 1763-NC01 is an active product, the NET-AIC was discontinued 12/31/2016.
  3. RS Logix v. 20.04

    I'm pretty sure you're not supposed to have to change the PLC to make 20.04 work.  I have downloaded and installed 20.04 on my VM but haven't had a chance to test it in the field.  If I were you, I would install 20.04 in its own virtual machine (or make a backup copy of your VM before upgrading the software) and then just try it to see what happens.
  4. I found this article on AB's site: (access level: everyone)   I'll try to remember to ask him tomorrow when he's in, but I seem to remember him having to do a lot of experimentation to get it to work.   Here's another KB article:  
  5. MCR for motor control and other AC items

    The Allen-Bradley safety-rated contactors we've bought are sealed so they can't be manually actuated.  We have some machines claiming to be built to European standards that have Siemens contactors used in redundant safety applications that have an accessible indicator on the front that may be able to be pushed to activate the contactor; I've never tried it. To get redundancy, you would add a second contactor in series with the one you have (if it's suitable) or replace it with 2 properly rated contactors.    
  6. MCR for motor control and other AC items

    I didn't find safety rating information on those part numbers quickly, which isn't surprising with their website.  I would reach out to your local distributor to verify that it's suitable for this application.  If it is, you still need 2 redundant contactors in series controlling the load with aux contacts from both being monitored by the safety relay.
  7. MCR for motor control and other AC items

    Acceptability of the control method depends on the level of the hazard determined by a proper risk analysis.   My opinion: If it's impossible to get hurt by the hazard, then by all means use a PLC controlled relay or contactor that's rated for the load voltage and current.  If there's any risk of injury, then use redundant safety-rated contactors rated for the load voltage and current and properly integrated into a safety-monitoring relay circuit.  I'm not aware of any problems mixing AC and DC voltages on a single contactor as long as the contactor is properly rated.
  8. Remote Access to CompactLogix PLC

    The alternative we found is Splashtop: Ironically, I found it by searching the internet to find a way to change our billing information (or turn off automatic renewal) for LogMeIn since it's not easy to find on their site.  Google led me to a post in their forums where someone suggested Splashtop as an alternative.  We could never get our IT to approve (or disapprove) it, though.
  9. Remote Access to CompactLogix PLC

    Our IT folks are very tightly controlled from corporate IT in Michigan (we're in Virginia) and things change periodically.  It seems that every time they upgrade the company network we lose access to more PLCs.  Right now, the building is set up with VLANs in the company switches that are completely controlled from HQ in Michigan.  Some of the switch ports will route our static PLC addresses, some won't.  It depends on which VLAN is set up on that switch port, which we have to beg and wait very patiently for corporate to change for us.  the fastest I've seen one reconfigured is about 2 weeks from submitting the ticket to having it complete.   What we've done instead: Each engineer has a laptop with all of the programming software installed.  That laptop stays at the plant and is logged in to the corporate network at all times.  With the blessing of our IT folks, we bought licenses of LogMeIn Pro, which allows us to use a web interface to remotely log into our laptops from anywhere with an internet connection.  We then have full remote control of the laptop without having to have someone local to the laptop give permission at the time.  Anything the laptop sees, we can see.  If we need to help an off-shift electrician with a particular machine, we have them plug the laptop into the machine, then we do our stuff.  This is the cleanest solution we've found with the way our network is set up.  Unfortunately, LogMeIn costs $150/seat/year.  We found a far more cost effective alternative that claims to be just as secure as LogMeIn but we were never able to get our IT folks to respond to our questions, either "yes, it's ok" or "no, don't use it".  So we're stuck with LogMeIn for remote access for now. We could log in to the VPN with our laptops from home (or anywhere) but that only gives us access to a very few machines in the plant that are successfully networked to the company LAN.
  10. Honestly, I can't answer your question.  That code was written by a colleague who has already left for the day.  I've done messaging to drives before, but from a Logix 5000 PLC, not 500.
  11. See if this is helpful for you (RSS file attached). MPT_VIS.RSS
  12. Explicit messaging.  See page 70 of the user manual for the embedded Ethernet/IP adapter: The example is for a CompactLogix, but I've seen it done very successfully with a MicroLogix 1400.  I may be able to find an example for you.
  13. Can you post a picture of the arrow and provide the model number of the panel?
  14. They are not rechargeable and they are also much more expensive than the average battery.  Which is another reason to minimize the time the PLC spends powered off.
  15. Have you gone to the Control Techniques website?  They may have sample code.