Steve Bailey

MrPLC Moderator
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Posts posted by Steve Bailey


  1. Quote

    i have also tried with another slave (Beckhoff BX900 with its internal com port) and it worked normal. so i can asume that there is something wrong configured in KL6041 module?

    I have to concur with your conclusion. Unfortunately I know nothing about configuring a Beckhoff PLC so I can't offer any suggestions.

    The checksum calculation is a check on the integrity of the data transmitted between the two devices. The sending device includes a two-byte checksum in the message it sends. The receiving device performs the same calculation on the message it receives, compares the checksum it calculates against the checksum it receives, and returns a fault response if they don't match. That was the basis of my questions about Modbus RTU vs Modbus ASCII and byte swapping. The checksum calculation for a Modbus RTU transaction is different than the checksum calculation for Modbus ASCII. The checksum calculation will be different if one device takes the low byte of each message word before the high byte and the other device takes the high byte before the low byte.


  2. The port setup looks OK. What command were you sending to the Beckhoff? The error code suggests that the checksum returned by the RTU slave is incorrect. If the Beckhoff shows a similar error when it receives the command from the VersaMax, it sounds like a difference in the way the checksum is calculated. Are you sure the Beckhoff is using Modbus RTU and not Modbus ASCII? Have you tried using Modbus master software running on your PC to test the Beckhoff's response?

    Edit: Or could the Beckhoff be interpreting the bytes in the opposite order of the way the VersaMax does?


  3. Where can I find what data is available from that NWS location? One of my customers gets alternative energy credits for using process steam for feedwater heating. They don't have a functioning temperature sensor on the incoming water line so they've been using a conservative constant value. If the NWS database includes water temperature along with flow they might be able to use that. There shouldn't be too much of a temperature difference between Housatonic river water at Coltsville and the Pittsfield city water main under Dalton Avenue coming from the Cleveland Reservoir.


  4. This sequence is from Proficy version 7.0. It may have changed a little in later versions.

    Go online with the PLC. From Proficy's "Target" menu, select "Online Commands". Then select "Show Status". In the pop-up that appears, choose the "Protection" tab to get to the menu where you can change your access level. 


  5. Perhaps the owners are starting to pay attention. The notice that Chelton cited when he started this thread no longer appears. It sure would be nice if someone from the ownership posted once in a while to let us know what's happening.

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  6. A new QP View comes out of the box with an administrator login name of "master" and a password "control". The password may be changed by the programmer of the runtime application, but have you tried logging in with it?

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  7. It was never "taken over" by Koyo. It was always a Koyo product brand labeled as GE, then TI, then Siemens when it bought TI's PLC business. Eventually PLCs became enough of a commodity item that Koyo was able to start PLC Direct to market their products directly to the end consumers without going through a network of distributors and factory reps. Then they broadened their range of products and changed the name to Automation Direct. 

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  8. SOR (Set Out Reset) is a one-shot coil. When the controlling logic is true the coil and all contacts associated with it are true for one program scan. Controlling logic must go false and then true again to get another pulse.

    D630 is a special sequencer contact associated with the CNT instruction addressed to address 630. The -] [- contact addressed to D630 #0001 is true when the accumulated value in CNT 630 is equal to 1. The -] [- contact addressed to D630 #0016 is true when the accumulated value in CNT 630 is equal to 16, etc.

    I don't blame you for wanting to replace it, but you can still buy replacement parts from Automation Direct. The product formerly known as the GE Series One (also the TI305 and Siemens/TI305) was manufactured by Koyo and is now sold as the DL305.

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  9. I don't believe you can rotate an alpha or beta motor without a motion controller connected to the amplifier. But it has been several years since I used them so things may have changed.

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  10. As far as I know every model Alpha and Beta amplifier has a set of motors it is compatible with. Generally the recommendation is to pair alpha motors with alpha amplifiers and beta motors with beta amplifiers for best performance even though there is some cross-compatibility between alpha motors and beta amps and beta motors and alpha amps.

    What kind of testing are you anticipating doing? What controller are you planning to use? Alpha and beta amps do not have any inherent motion control capability.


  11. Quote

    About a year ago I was conducting controls training in California for a very large city government agency. During a programming demonstration I labeled a touchscreen button "Manual" and was immediately interrupted by the students. The city/company policy is that they are forbidden from using the word "manual" because it has "man" in it, and therefor may be offensive to some. In fact, I was told it's a written policy, right in the employee handbook.

    Would you be willing to identify the "very large city government agency"? Because without specificity it sounds suspiciously like an urban legend.


  12. Those files are backup files created by Logicmaster. Here's a method to use them.

    First, using Logicmaster, create a new folder using the correct name. Save it. Then go into edit mode and when Logicmaster asks if you want to make a backup, answer 'yes'. Add a rung of logic. It doesn't matter what you put in it. It will be overwritten when you restore from the backup files. Save your edits and exit Logicmaster.

    Now locate the project folder with Windows Explorer. The normal location is C:\LM90\Myfolder. You should also see C:\LM90\myfolder\Backup. That 'Backup' directory was created by Logicmaster. Copy and paste the PKA, PKC, PKL, PKO and PKR files into the C:\LM90\myfolder\Backup directory. Let the paste procedure overwrite the existing files.

    Reopen Logicmaster, launch your project and use Logicmaster's restore procedure.

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  13. You'll need to run Logicmaster on an older computer running nothing newer than XP. Best success will be on a machine with  real serial port. I've not had much success uploading/downloading with Logicmaster through a USB/serial converter. Once you have Logicmaster running you can connect to any of the three serial ports. The two ports with cables connected in your picture are RS485. The unconnected port 1 I RS232.

    Are you sure the program in the PLC was created using Logicmaster? If it was created with VersaPro or Proficy Machine Edition, Logicmaster won't be able to open it.


  14. What CPU does your new project default to and what CPU do you want to use? If the PWR321 power supply is not compatible with the CPU module it won't show up in the catalog. I think the default CPU for a new 90-30 project is the CPU374 which requires a high capacity power supply like the PWR330.

    You need to double-click on the "Set temporary IP address" to launch the tool. It allows you to enter the MAC ID of the module and assign an IP address to it. The address you assign will not survive a power cycle. Once you have assigned one you will need to download a hardware configuration to the CPU to make it persistent.

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  15. The GE PLC product line has been acquired by Emerson. The software you need is called Proficy Machine Edition. The lowest priced version of it will be sufficient for the model PLC you have. You need to get in contact with a local distributor to arrange for a download from the support site.


  16. There is no requirement that analog input modules and analog output modules be installed in pairs. Did you download the new configuration to the NIU? Did you get an indication in the feedback zone that the download was successful? How are you communicating with the remote I/O? If you are using EGD, did you modify the appropriate produced and consumed EGD exchanges?

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