Knowledge Base /
Technical Notes
VIM Network Gateway FAQs
By Tom Freiberger
Product: DeltaV Virtual IO Module - VIM2

The following is a list of frequently asked questions about the VIM Network Gateway.

Why do I not see my VIM in the Decommissioned VIMs list?

Do I need to add all four cards in DeltaV Explorer that are emulated by the VIM?

Why I am getting “Binding Error” when I try to commission my VIM?

Why I am getting the “Socket Connect Failure”?

What IP address should I assign to VIM’s placeholder in VIMNet Explorer?

Why am I getting “Bad Device Failure” on dataset level in DeltaV Diagnostics?

Why I am getting “Network Error – refused to connect”?

Why won’t the VIMNet Explorer install on my PC? The installation wizard won’t start.

I am trying to add more than 16 devices and I cannot do it. Why not?

What should I do if I am not seeing data in DeltaV on some registers that should read values from Modicon PLC?

Why am I getting this error in VIMNet Diagnostics: “Serial Card Download required”?

I have Modbus TCP VIM, and floating point data is coming across in a wrong format. How can I get it to show up in the correct format?

Is 32-bit integer data supported with DF1 datasets?

Can I have a Class 1(ENBT) connection with redundant VIMs?

I have Control Logix communicating to the Ethernet/IP VIM. What should I set the Special Data 4 to?

I have lost my VIMNet Explorer configuration file (.VIO). How can I recover or rebuild the configuration?


Why do I not see my VIM in the Decommissioned VIMs list?
There are two common cases where VIM will not show up in the Decommissioned VIMs list: 1. when it’s already commissioned; 2. if it cannot communicate with the PC due to network or NIC issues;

The first step is to determine if the VIM is in a commissioned or decommissioned state by looking at the VIM’s LEDs. I. If the VIM’s active LED is lit and the VIM appears in the Decommissioned VIMs list with a red X, proceed with the reset command as described below. Before performing the Reset command on a VIM, please verify that it is not online with another system. To Reset a VIM, right click on the VIM in the Decommissioned VIMs list and select Reset. The VIMNet Explorer will send a decommission command over the network, and clear the VIM from its list. The VIM will then re-appear as an unconfigured, decommissioned VIM in the VIMNet Explorer list and you can commission it to new placeholder again. II. If the VIM’s active LED is lit but the VIM is not showing up in the Decommissioned VIMs list, follow these steps: Step A. Reboot your PC with the network cable plugged in to the NIC port. Occasionally, the Windows XP machines do not recognize the broadcasts, if the PC was last rebooted without network cable connected to it. Step B. Change the subnet mask of the NIC so that it can see wider range of IP addresses. E.g. (255.0.0.0). Step C. Search for this VIM in the Decommissioned VIMs list and if your VIM shows up with a red X, follow the procedure described above to reset it. Contact Mynah Technical Support if you are still not seeing your VIM.

back to top

Do I need to add all four cards in DeltaV Explorer that are emulated by the VIM?
Yes. You must add all 4 cards for each VIM even if they are not used, but you can disable the ports on the unused cards.

back to top

Why I am getting “Binding Error” when I try to commission my VIM?
You will get this error if the Network Settings and Physical Network properties do not match. The NIC that is connected to the VIM network must have a static IP address. The Physical Network properties in the VIMNet Explorer must be set to the NIC’s IP address. The subnet of your NIC must match the subnet of the VIM placeholder in the VIMNet Explorer. If the error persists, contact MYNAH Technical Support.

back to top

Why I am getting the “Socket Connect Failure”?
This error will appear if the Network Settings and Physical Network properties do not match. The NIC that is connected to the VIM network must have a static IP address. The Physical Network properties in the VIMNet Explorer must be set to the NIC’s IP address. The subnet of your NIC must match the subnet of the VIM placeholder in the VIMNet Explorer. If the error persists contact Mynah Technical Support.

back to top

What IP address should I assign to VIM’s placeholder in VIMNet Explorer?
You can assign any unique IP address that is within a range of your VIM network. If the VIMNet Explorer reports “Commissioned Bad” for your VIM, then make sure there is nothing else on the network with the same IP address. The VIM’s placeholder must have a subnet mask that is same as the NIC’s subnet mask. The VIM network must a completely separate network from the DeltaV network.

back to top

Why am I getting “Bad Device Failure” on dataset level in DeltaV Diagnostics?
This error usually means the target devices are unreachable. You should verify that you can ping the target devices from the command prompt. You should also make sure the dataset is configured correctly. To troubleshoot this further, you can drill down to the dataset’s status in DeltaV Diagnostics and see if there is any particular error message. If the message is not self-explanatory, you should contact MYNAH Technical Support.

back to top

Why I am getting “Network Error – refused to connect”?
Start troubleshooting this issue by making sure the target device is connected and you can ping it from command prompt from the PC that is connected to VIMs. This error usually means PLC is not responding to the VIM’s pings. Make sure it is connected and check the PLC’s settings. If you have set the number of simultaneous messages to a number greater than 1, change it back to 1 and see if the device will start responding. Contact MYNAH Technical Support for troubleshooting steps.

back to top

Why won’t the VIMNet Explorer install on my PC? The installation wizard won’t start.
Contact MYNAH Technologies for different installation software.

back to top

I am trying to add more than 16 devices and I cannot do it. Why not?
If you have Modbus TCP VIM Network Gateway and plan to put in place more than 16 devices, you need to contact our office and obtain an upgrade to a Modbus version later than 3.6.8. as well as the VIMNet Explorer v 9.0.8.0. Note that up to 32 devices can be added on the network in the simplex applications, while in redundant you can add up to 16 devices. Note that Ethernet/IP firmware supports up to 16 devices on the network in both simplex and redundant applications.

back to top

What should I do if I am not seeing data in DeltaV on some registers that should read values from Modicon PLC?
This is most likely due to configuration mismatch. The dataset’s start address in the DeltaV configuration should be the set to the offset and not full register address. For example, if you are trying to read values from 40,100 holding registers, you need to set the Start Address to 100, which is an offset. For more details on how to configure the datasets, refer to the Modbus TCP manual, or contact MYNAH Technical Support.

back to top

Why am I getting this error in VIMNet Diagnostics: “Serial Card Download required”?
It is most likely because the VIM will emulate cards only if all 4 cards are added in. You can either perform auto-sense or add all four cards in manually, download the controller and the error should go away. Another reason for this error is that VIM hasn’t received the full serial card download because of the configuration error that stopped the download. For example, if you configure the floating point dataset with more than 50 values, you will get this error. If this issue persists, please contact MYNAH Technical Support.

back to top

I have Modbus TCP VIM, and floating point data is coming across in a wrong format. How can I get it to show up in the correct format?
To customize the data representation in your floating point or 32-bit integer dataset, you can use the Special Data 1 and 2 parameters as flags. If you leave Special Data 1 parameter equal to 0, then the floating point and 32-bit data is represented as received. Depending on the byte order of the value that you get in your DeltaV system, you can set Special Data 1 parameter to 1, 2, or 3 to customize the format. The Special Data 2 parameter needs to be set to 1 when data is not read as 2 Modbus 16-bit registers but as individual floating point or 32-bit values. Contact MYNAH Technical Support for more details on this solution.

back to top

Is 32-bit integer data supported with DF1 datasets?
No, the 32-bit integer data is not supported with DF1 datasets, and it is recommended to use the ENBT dataset to bring the value in 32-bit format across. If you don’t want to change the PLC’s configuration, you can use this alternative. Map the 32-bit integer tag to file number in the Logix, and read in to DeltaV using 16 bit integer dataset with double number of registers. Your 32-bit data will show up in the DeltaV on two consecutive registers in high and low word order, low first, and then high word. Contact MYNAH Technologies for more details on this solution.

back to top

Can I have a Class 1(ENBT) connection with redundant VIMs?
No, the ENBT connections are supported only in simplex VIM configurations and simplex PLC chassis. This is because of the Master/Slave relationship between VIMs and Logix controllers. For ENBT connections, the VIM behaves as a slave; therefore, if the Rockwell PLC is in a redundant chassis, you cannot use the ENBT connections either.

back to top

I have Control Logix communicating to the Ethernet/IP VIM. What should I set the Special Data 4 to?
The Special Data 4 parameter is used to set the CPU’s slot number. If the Logix’s CPU is in the first slot (slot 0), configure this parameter to 1; otherwise, use this formula to calculate the value for this parameter: (256*slot )+1. Note that this parameter is used only for Logix PLCs.

back to top

I have lost my VIMNet Explorer configuration file (.VIO). How can I recover or rebuild the configuration?
As of VIMNet Explorer v9.0.12.13 you can automatically recover a Modbus TCP VIM with firmware v3.6.10 or later. There is no automatic method for recovering an Ethernet/IP VIM (IOD-4102 and IOD-4104). Please follow the manual rebuild procedure mentioned in this KBA: http://www.mynah.com/content/steps-required-rebuild-vimnet-explorer-conf...

back to top