Section 11: HART Communications Instruction Manual
April 2017 LIQ-MAN-56
90 HART Communications
11.4 Diagnostics Available via HART
11.4.1 Status Information -- Device Status Bits
Bit 0 Primary Variable out of Limits:
This bit is set when PV is out of its limits.
Bit 1 Non-primary Variable out of Limits:
This bit is set when non PV is out of its limits.
Bit 2 Loop Current Saturated:
This bit is set when the Analog Output 1 current is less than 1.0 mA or greater than
22.0 mA and the Device Status Bytes bit 3 is not set.
Bit 3 Loop Current Fixed:
This bit is set when Analog Output 1 does not follow the process. This bit is cleared
when Analog Output 1 follows the process.
Bit 4 More Status Available:
The “more status available” bit will be set when the device status condition occurs (i.e.
bit goes from 0 to 1) on at least one of the Additional Transmitter Status bits are set.
Bit 5 Cold Start:
This bit is set when a Master Reset is performed either by Command 42, or a power
cycle. This bit is cleared after the first response or burst. In the case of a burst, the
first burst always goes to the primary master.
Bit 6 Configuration Changed:
This bit is set when the last bytes of an EEPROM writing sequence is completed. Since
EEPROM writes are delayed until after the response, the immediate
acknowledgement will not have the bit set, however, after the EEPROM write
completes, the bit will be set. This bit applies to all EEPROM writes whether or not
they apply directly to the configuration of the instrument or not. This bit is cleared
when Command 38 is executed.
Bit 7 Field Device Malfunction:
This bit is set when any of the following conditions is true, and cleared when all of the
following conditions are false:
a) There is at least one main board fault.
b) There is at least one Sensor 1 fault.
c) There is at least one Sensor 2 fault.
11.4.2
Status Information – Extended Device Status Bits (HART 7 only)
Bit 0 Maintenance Required:
Any calibration error will set this bit. Any calibration for either Sensor 1 or Sensor 2 that
fails will set this bit. This bit gets cleared if all device variables are calibrated successfully.
This bit is set to indicate that, while the device has not malfunctioned, the Field
Device requires maintenance.
Bit 1 Device Variable Alert:
This bit will get set when at least one of device status byte of all the valid Device
Variables does not equal to "good and not limited" (i.e. the higher 4 bits not equal to
To Next Page
