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.
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.
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
In reply to David Tudor Evans:
Ed Smigo
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.
In reply to Andre Dicaire:
In reply to Muzammil Shaikh: