Using fieldbus technology in the control strategy > Troubleshooting fieldbus loops

Understanding fieldbus block errors

Function block errors show up as yellow question marks () in Control Studio online. DeltaV function blocks, including those capable of running in fieldbus devices, report standard function block error information through the BLOCK_ERR parameter. Each block's BLOCK_ERR parameter is documented in Books Online. Function blocks that run in fieldbus devices report additional, device-specific block error information through BLOCK_ERR. You must refer to the device documentation to understand these device-specific errors. Also, more information on device block errors may be available from the device's Status/Conditions context menu item. Among the most common block errors seen with the DeltaV system are Out of Service, Input Failure/Bad PV, Configuration Error, Link Configuration Error:
  • Out of Service: One or more of the blocks (function block, Resource block, Transducer block) is in Out of Service (OOS) mode. To see the function block mode, look at its MODE parameter in Control Studio. To see the Resource and Transducer blocks' mode, select the device in DeltaV Explorer, select StatusConditions, and look for the mode information.

  • Input Failure/Bad PV: Often, this is caused by an incorrect channel, incorrect choices in the XD_SCALE parameter, failures in the Transducer block, or the Transducer block is in OOS mode.

  • Configuration Error: Most likely this is caused by an incorrect channel and/or incorrect choices in the XD_SCALE parameter.

  • Link Configuration Error: This is often device-specific and could mean that the device does not accept a certain configuration or a link is improperly configured. For example, not all devices support a configuration in which two fieldbus links from one function block output running in one fieldbus device are connected to two inputs in another device. Refer to the device documentation's description for this block error.

  • Device-Specific Errors

    The following errors refer to internal device errors that may be serious and may require service or device replacement. Refer to the device documentation if you encounter these errors:

    • Lost NV Data

    • Lost Static Data

    • Memory Failure

    The following errors are used by the manufacturer to alert users of a possible device problem and to alert users that the device needs maintenance now or in the near future:

    • Device Needs Maintenance Now

    • Device Needs Maintenance Soon