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Flex727

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Posts posted by Flex727

  1. MODBUS IP Network Re-Connect Functionality

    in Vision & Samba PLC + HMI Controllers & VisiLogic Software

    Posted

    Did something about the "re-connect" functionality change with Visilogic 9.7? I've been using several iterations of Visilogic over the years and have always been impressed with how the PLCs will immediately reconnect when communications are disrupted (e.g. ethernet cable is pulled and re-inserted, or one of the slave PLCs is powered off then on again). Now that I've upgraded to 9.7.24, the Master PLC no longer seems to attempt to reconnect after a disruption.

     

    I do have SB168 SET at power up.

     

    System details:

     

    Using MODBUS IP over ethernet.

    3 V570 PLCs, 1 Master and 2 Slaves

    All PLCs are running the latest firmware

    All the networking attributes (timeouts, retries, etc) are set to the default

     

    Everything connects immediately upon power up, but if the connection is lost for any reason, no attempt is made to re-connect. I did not see this behavior ever with previous projects running under Visilogic 9.4 using the exact same code for the networking aspect. My code for the Ethernet and socket initialize & connect is the same as shown in the example project that comes with Visilogic.

     

    Besides SB168, is there anything specific I should check for?

  2. Retrofits--what do you look for???

    in ...I have a project...what hardware do I need?

    Posted

    Our most common request is for the PLC to be able to notify specific people when an alarm occurs, either by page, text message, or email. While we can certainly do that, there are certain recurring costs and requirements for that the customer rarely wants to pay (plus it's usually vetoed by the IT group). We do utilize Remote Operator from time-to-time to provide remote access, say at the engineer's desk, so that he can take a quick look at what's going on without having to make the trip to the process tool. When the PLC is located in a particularly remote or difficult to access location, we will very often provide (sell) a remote monitor box with it's own PLC that can be located anywhere. Customers seem to like this.

     

    Another common request is to be able to provide data to the customer's SCADA or monitoring system. I like to use MODBUS IP for PLC-to-PLC communications and generally collect all the requested data at one PLC in a contiguous memory array then set that PLC up as a MODBUS slave using port 502. That always works well and has made many customers happy, particularly the ones who insist we use PLCs that match their system (often Siemens or A-B ). Our platform is currently Unitronics (Vision) and we won't quote anything else.

     

    Often the system we are upgrading will have a touchscreen HMI (often Maple Systems or Beijer), but they are usually not full color. I try to use the color capability to add some wow factor and make the user interface much more intuitive. The one difficulty I tend to have is that the screen I'm replacing usually has 640x480 resolution and the V570 we typically use is only 320x240 (Cara has heard me complain about this before). On a big system we will occasionally use a V1210, but unless it's really necessary, we like to stay with the V570. I have developed a nice user interface for the V570 over the years that we tend to stick with on most products.

  3. Retrofits--what do you look for???

    in ...I have a project...what hardware do I need?

    Posted

    That's a large percentage of what we do. We will take a customer's system and upgrade it to add automation and intelligence to improve uptime & capability, reduce labor costs, and improve safety. The worst problem is getting accurate information about the components in the system, especially sensors. Further, while we build and test the retrofit components in the shop, when we take it to the field many unanticipated situations occur. The systems people in our company realized early on that it was important to bring the programmer along (me) on the install because there are often minor and even major changes that must be performed on the code to make it work properly on the customer's system. While that reduces some of the stress in getting the code right prior to the install, while we're at the customer site we have limited time and I must work quickly under pressure to get everything exactly right before we leave. It also provides the customer an opportunity to suggest minor changes to the software and user interface to provide them some customization. It's a challenging environment that I love.

     

    One customer was looking at two alternatives to upgrading their chemical delivery system in their semiconductor wafer fab. Our competition required them to remove the system from their wafer fab and ship it overseas to be upgraded with a 6-8 week turnaround. We told them we would come into their plant, upgrade their system in place, and complete the work in 3-5 days. They didn't believe we could do that and were seriously considering both options until the group manager walked into a meeting looked at the two options and asked them why they were still considering our competition. We got the job, completed the task on time, and was awarded work on 8 additional systems. Before we started we were asked, "If you get finished and it doesn't work, can you put it back the way it was?" "Uh, no, but we won't leave until it's working perfectly". We've never yet failed to overcome the problems we've encountered. I'm not sure there is anyone else in the country that can do what we do routinely.

    • Upvote 1

  4. Transfer data between PLCs using MODBUS IP over Ethernet

    in Vision & Samba PLC + HMI Controllers & VisiLogic Software

    Posted

    Thanks, Cara. I did it a bit differently this time. I truly have a mix of MIs & MBs and a mix of reads and writes and don't see the offset this time. Before, I think I was just reading a single block of MIs. Also, I'm now using Visilogic 9.7.24, whereas before I was using 9.4.0. I'll have to revisit my previous project to look for other differences.

     

    I'll say this, that R/W Mixed Data FB is mighty handy for what I do.

  6. Graphic Download Problems

    in Vision & Samba PLC + HMI Controllers & VisiLogic Software

    Posted

    During program development I will usually end up downloading a project to a single PLC many dozens (sometimes hundreds?) of times. Occasionally something eventually corrupts the image file in the PLC which never gets corrected in subsequent downloads of the same project, even if the images change. In those instances, downloading a blank project file then re-downloading the original project file completely fixes the problem.

    • Upvote 1

  10. Issues setting bits with a state machine

    in Vision & Samba PLC + HMI Controllers & VisiLogic Software

    Posted

    It's okay (if the logic is correct) to use Set and Reset coils in multiple places in your project, but NEVER use multiple direct coils with the same address. In your case, you're trying to trigger something off multiple conditions. Use a separate direct coil (or Set coil, if appropriate) for each condition, then at the end of your subroutine, place all those separate MBs as contacts in parallel to trigger MB10.

     

    You can easily check for multiple coils of the same address by right-clicking on the Operand (when NOT Online) and selecting "Find...". All the instances of the operand will be listed at the bottom of the screen and you can double-click on any of them to take you to the location.

  14. Ethernet and the V570

    in Vision & Samba PLC + HMI Controllers & VisiLogic Software

    Posted

    Hi

     I've have completed an aplication using a V570 controller. I am planning on using a 2nd V570 as a remote panel. I have installed ethernet cards in both of the V570's and planned to interconnect using the ethernet cards through a simple 5 port wired switch.(I have very little experince with comms of this nature) Which I had thought would also allow me to conncect my PC also and connect to both panels.

     I was working on just trying establish comms with the primary V570 and could not even get it to ping. Would I be better off using a router instead?

     I watched all of the ethernet webinar videos and think I'm setup correctly but am unable to ping.

    I would apreciate any advice, help or hints anyone might have.

    Thanks

    Mrdegold

    I do this exact thing all the time and have no problems whatsoever using MODBUS IP over Ethernet and a digital switch.

     

    Make sure your PC and the PLCs are all on the same subnet to minimize complications. PC firewalls can also be an issue, so I would start with IP addresses in the range of 192.168.1.xxx until everything is running smoothly, then change later if you need to.

  16. communications difficulty with V1210

    in UniLogic Software

    Posted

    Here is a list of things you need for PC to PLC communications over Ethernet:

     

    1) Both PC and PLC need to be on the same subnet (i.e. first 3 triads of the IP addresses should be the same).

     

    2) You need to set a PLC Name in the PLC ladder. Be sure you power cycle the PLC after updating any communications settings on the PLC.

     

    3) You need a crossover cable or a digital switch, hub, or Router.

     

    4) In Visilogic, select "TCP/IP (Call)" in the Connection/Communication settings. From there, enter the correct IP Address, Protocol (TCP), Port Number (20256), and the correct PLC Name.

     

    Occasionally, firewall software on the PC can interfere. You can usually overcome this by selecting 192.168.1.xxx as the subnet. Be sure the IP address you select for the PLC is not duplicated elsewhere on your network.

     

    Also, be sure you are not assigning Socket 1 to another port. While you do need a TCP/IP CARD INIT block (use SB2 as a gate), you don't need a SOCKET INIT block since Socket 1 will default to port 20256 and will work by default.

     

    If you don't know what to do with the "Subnet Mask" and "Default Gateway" sections of the Card Initialization block use the following:

     

    Subnet Mask: 255.255.255.0

    Default Gateway: 192.168.1.254 (assuming you used 192.168.1.xxx as your network subnet)

  17. SCADA to PLC and PLC to PLC communications

    in Vision & Samba PLC + HMI Controllers & VisiLogic Software

    Posted

    I regularly connect PLCs together to communicate data between them. I usually use MODBUS IP when connecting by Ethernet. As long as the PLCs are on the same subnet, they will communicate with ease and are reliable. You don't even need a router, hub, or switch if there are just two PLCs - just a crossover cable. There are example projects for Ethernet communications that come with your Visilogic installation. Go to Help\Examples\ and drill down till you find "V280_Ethernet_TCP_MODBUS_IP_Master.vlp" and "V280_Ethernet_TCP_MODBUS_IP_Slave.vlp". The functions are the same for all of the Vision products.

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