HART error conditions effect on Analog Output Channel

We are facing issues with HART enabled Analog Output channels. This is for a specific manufacturer only (Metso Automation ND9000H). At random time intervals, the channels are going to BAD status and AO function block mode goes to IMAN mode. This gets cleared only after HART alarms are cleared and then either redundant card is switched over or "Clear saved fault information" command is given. Customer requirement is even if HART alarms are received, the 4-20mA loop should not go BAD. When the channel is changed to Non-HART Analog output channel, no issues of valve going in IMAN are observed. DeltaV version is R5.1. 

P.S:- The positioner installed has HART DD File Rev-4 but Rev-4 DD File is not available for R5.1 revision hence the channel cannot be autosensed in DVExplorer.

  • have you looked at setting HART_ERRORSs on the channel to Ignore?  In SIS, HART errors are ignored by default, and we still have HART access to the device.  

    The other approach is to use FIELD_VAL_PERCENT rather than HART_FIELD_VAL on the IO_READBACk.  

    Form BOL:

    Customizing Control on Error Conditions

    In some cases, you might want to use HART data even though the instrument is reporting certain error conditions. The HART_ERRORS parameter allows you to select which HART status error values are ignored in your control strategy.

    The HART_ERRORS parameter masks HART error conditions that you determine are not required for your application. For example, you might have a measured variable that is outside limits occasionally but is not a problem for the process. You can select the Ignore PV Out of Limits for All PV Status option in the HART_ERRORS parameter to disregard this error condition.

    You modify the HART_ERRORS parameter by selecting the channel properties and checking one or more of the following actions:
    • Ignore PV Out of Limits for All PV Status — Primary Variable (PV) values that are higher or lower than the configured limits are ignored when determining PV statuses.
    • Ignore NPV Out of Limits for All NPV Status — Non-Primary Variable (NPV) values that are higher or lower than the configured limits are ignored when determining NPV statuses.

    • Ignore PV Output Saturated for All PV Status — PV values that are output saturated are ignored when determining PV statuses.

    • Ignore PV Output Fixed for All PV Status — PV values that have a fixed output are ignored when determining PV statuses.

    • Ignore FLD Device Malfunction for All Status — Values determined during a field device malfunction are ignored when determining statuses.

    Note

    The default value for these actions is disabled (False). That is, these status conditions are not ignored. When you enable these actions, the block ignores the specified statuses.

    Andre Dicaire

  • Sounds like HART communication errors. This usually happens due to installation issues. Using HART for position feedback requires a "digital grade" installation. Make sure the loops are designed and installed according to the HCF_SPEC-054 specification. The HART communication application guide HCF_LIT-039 and the HART field communication protocol technical overview HCF_LIT-20 include some design guidelines as well as other useful information. They are summarized in this essay:
    www.linkedin.com/.../

    Most common design mistakes and installation issues for HART:
    -No HART pass-through
    -Cable not meeting HART specs
    -Missing loop resistance
    -High loop resistance
    -High loop capacitance
    -Safety barrier not HART compliant
    -Cable routing
    -Wrong shielding
    -Housing not grounded
    -No HART input filter
    -No HART output filter
    -No HART line conditioner
    -Device not HART compliant
    -No DD file available
    -Noisy power supply
    -Master conflict
    -Burst communication contention
    -Address setting
    -Command 48 not supported
    -System not HART7 compliant
    -Slow polling
    -DD not loaded on DCS
    -DD not loaded on IDM software
    -DD not loaded on portable
    -Wrong DD file
    -Analog output tight-shutoff
    -Wrong grounding
    -Shield shorted
    -Shield continuity
    -Cable damage
  • Hi Andre,
    Just a quick general question about HART accessibility for Delta V v.14 and HART7 in our not yet built plant.  We have Siemens S7s and Rockwell Controllogix systems with HART enabled I/O.  The Delta V is talking to these via IP Ethernet Implicit Class 1.  Do you know if we will be able to access the HART information without further Delta V hardware?
    Thanks Dave Evans
  • In reply to David Tudor Evans:

    DeltaV HART 7 capability only applies to DeltaV HART I/O. If the instruments are wired to S7 and Control Logix it is up to those PLC vendors to read HART and make it available via Ethernet IP to the DeltaV system. On the flip side I do not believe many host vendors other than Emerson are compliant with HART 7 so the devices would likely need to be configured as HART 5 or HART 6 devices.

    Ed Smigo

  • Thanks Eddy.  I am trying to find this out from our contractor but it is a bit opaque at the moment.  We already have Emerson U/Sonic level transmitters that are HART 5 so it may not be such a big issue.  But if anyone knows the answer to the specific hardware question, I’d be grateful.
    Thanks.
    Dave Evans
     
     
  • In reply to David Tudor Evans:

    There are two ways to get the HART data out of the ControlLogix and in to DeltaV.

    1. The ControlLogix controller can access basic HART data via the IO module connection and it can access Device specific HART data via message blocks. Once that data is in the CLX tag database, you can use EtherNet/IP or OPC to share that data with DeltaV.

    2. The ControlLogix HART IO has the HART modem which can be accessed via Spectrum Controls "Connects" software thus making a virtual serial port for Emerson's AMS software. Any device management software can use the "Connects" software as it emulates a serial HART modem e.g. COM2, COM3, COM4, COM5... etc. and seamlessly passes data across the network, across the 1756 backplane, and across HART to the field instrument.
    www.spectrumcontrols.com/.../
  • In reply to pmhamilton:

    HART data for device management like configuration, diagnostics, calibration management, and monitoring internal variables etc. is not really a function of the DCS (DeltaV) where the process operators sit (control room). They look after the process, not the instrumentation. The devices are managed by the I&C team. This is instead done from AMS Device Manager, typically from the maintenance office. So you want to bring HART data from the ControlLogic, Siemens, or other PLC into AMS Device Manager. The direction the industry is going is to no longer do this via virtual COM ports, but via Ethernet. In case of HART and WirelessHART this is done using the HART-IP protocol over Ethernet. So see if the PLC comes with HART-IP "pass-through" to tap the HART data into AMS Device Manager. Learn more from this essay:

    Implementing HART-IP in Plants - The Ultimate User Guide

    www.linkedin.com
    Ethernet is taking the place of RS485 in plants and Ethernet-APL will eventually take the place of 4-20 mA. Ethernet is used for the control network since over 20 years ago.

  • Thanks Jonas.  We have various locations where DeltaV will be available on the plant.  I am concerned with how to interface the HART signals from foreign devices into AMS.
     
    We are using IPEtherNet Class 1 Implicit comms to the Siemens S7 etc.  which is great because it is the only communication we have to the DeltaV.  My concern is whether we need HART enabled I/O modules on the Siemens / Rockwell etc. end.
     
    In the notes it states the ControlLogix controller can access basic HART data via the IO module connection and it can access Device specific HART data via message blocks. Once that data is in the CLX tag database, you can use EtherNet/IP or OPC to share that data with DeltaV.  Also an alternative would require new hardware…..the HART modem……”The ControlLogix HART IO has the HART modem which can be accessed via Spectrum Controls "Connects" software thus making a virtual serial port for Emerson's AMS software.”
     
    The educational essay doesn’t address this for Siemens, so I’m talking to the various vendors to track it down.
     
    The main change I’ve noticed in my 40 years in process control is that now IT is waking up to the fact that there are servers in DCS architectures.  A mini turf war seems to be playing out.
     
    Thanks for your advice Jonas.
     
    Best Regards,
     
    Dave Evans |   | Lead Control Systems and Instrumentation  | Perth, Western Australia | Level 7, 197 St Georges Terrace, Perth, WA, 6000 | *: PO Box 7423, CLOISTERS SQUARE PO, WA, 6850 | (: +61 8 9347 4321 | ): +61 475 250 796 | *: Dave.Evans@albemarle.com | www.albemarle.com 
     
     
     
     
  • Thanks pmhamilton.
     
  • In reply to David Tudor Evans:

    HART-IP is the best. Siemens PLC if fitted with HART compatible IO cards usually support "HART over PROFINET". This is also supported in AMS Device Manager so that may be a good way. You can bring individual pieces of HART data into DeltaV through OPC, but not OPC into AMS Device Manager. But AMS Device Manager is really a better place for device management like configuration and diagnostics, so if you can bring the data to AMS Device Manager that would be better.

    Get both IT and OT to refer to the IEC62443 / ISA99 and the US ICS-CERT standards to avoid turf war between IT and OT. There shall be a DMZ at level 3.5, with IT managing layers above and OT the layers below. See here:
    us-cert.cisa.gov/.../NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf
  • In reply to Andre Dicaire:

    I had ignored all the HART_ERROR parameters and still received the same errors. At random intervals, the AO function block goes to IMAN mode. Can this issue be due to missing version of DD File in DeltaV?
  • In reply to David Tudor Evans:

    David, specific to your question on HART 7, most of the features of HART 7 play to the WirelessHART implementation. A few are directly implemented in DeltaV, such as the 32 character device tab and the individual Hart Variable Status. in HART 5 you get the 8 character HART Tag, which is still in HART 7, and the status of the device is applied to all four HART variables.

    DeltaV HART IO channels continue to use the polled communication rather than periodic schedule communication which we find in Wireless. Since we have a single device on the wire, polling the data works for HART 5 and HART 7 devices. That simplifies installation and you don't have to worry about the Device version to get the HART data into control modules.

    The Smart Commissioning tools in DeltaV v14 make better use of the 32 character long tag but if the device does not support this, no problem. I don't think there is that much of an issue connecting HART 7 devices the HART 5 compliant IO channels, as they will simply not use the new features of HART 7.

    As for AMS DM, that has been covered by Jonas and others on this thread. The main thing to understand is that HART IP and HART Modems allow the management software to pass HART commands and receive their responses. The HART IO cards simply pass those commands through to the device. So even if the IO card and system implement HART 5 commands to poll data from the device, the HART Modem or passthrough mechanism will still allow AMS DM to interact with the device with the latest DD and pass HART 7 commands to the device.

    In DeltaV, we also have Device Alerts that gather the additional status words and map these into the Device Alerts. That requires that the correct DD be loaded into the system so DeltaV can correctly map all these additional conditions, beyond the standard HART Status word. The HART status word gives the basic PV Saturated, Condig Change flag, Out of Service etc, mapped to the HART_ERRORS conditions, which affect the HART channel status. When "more statuses" is flagged, DeltaV will retrieve them for the Device Alerts, and pass these through to AMS DM to trigger the Alert Monitor in Device manager.

    This is where you will see a difference in reporting of device alert data to AMS DM when using a HART modem or HART IP. These are set up in AMS Device manager to be polled by DM. DeltaV does this poling and proactively sends the alerts to AMS DM. Polled devices can take minutes to report a condition as it must be polled with a HART command coming from the AMS server, one device at a time.

    This does not affect interaction with the device by a user, as commands are sent in real time while editing or viewing a device.

    You will get HART 7 device data via AMS DM and the control system will get what ever it supports. You will not be limited by the IO card's HART implementation.

    Andre Dicaire

  • In reply to Muzammil Shaikh:

    An AO channel that sets a BAD status will cause the AO block to go to IMAN. There can be other reasons beyond HART data that sets the AO channel bad. One is the channel unable to drive the mA signal required due to excessive impedance in the loop. A loose wire that periodically cause an "Open Circuit" condition or a faulty field device that affects the mA signal.

    You could disable HART on this channel and see if these events continue to happen. That would confirm it is not HART related. Loose wire or whatever will still cause the same IMAN conditions.

    Andre Dicaire

  • In reply to Andre Dicaire:

    All great suggestions from Andre. You also might go to DeltaV Diagnostics and look at the channel statistics and the device statistics and see if you are getting comm errors/no response from the device. This can help isolate your issue(s). If the device is having a hard time communicating, device channel statistics will tell you that which you might want to troubleshoot if it's one of the issue Andres was mentioning.
  • In reply to Andre Dicaire:

    Yes we have Disabled the HART option on these channels and observed for some days, and there is no issues when HART option is disabled. The AO stays in CAS mode and does not goes to IMAN. We have also replaced the accessories( Barrier, Card, Card Term Blocks), and found no issues with them. Also i do not have DD File installed in DeltaV Explorer (R5.1) for this specific HART Positioner as it is not available on our Emerson website nor in valve manufacturer's website.