Honeywell SmartLine Multivariable SMV800 Series User Manual page 266

Diagnostics / message
Comm Vcc failure and / or
Sensor Critical Failure
254
Tool
(DD Host / Details/Resolutions
DTM Host )
Possible scenario:



DD Host /
DTM Host

Resolution: Older Sensor board (part number: 50086421-001)
with comm vcc error– Replace with latest Sensor board with
Temperature sensor firmware 1.xxx207 or higher.
Newer Sensor board (part number: 50086421-021) with Sensor
Critical failure: Power cycle after download
Or before downloading flow configuration, map the Analog
output to a variable other than flow (ex: Pressure, Temperature,
Static Pressure)
SMV800 Transmitter User's Manual
Comm Vcc failure can happen without any
other failures when the User has older
Temperature Sensor board (Terminal
module) that does not have the Vcc
regulation mechanism at low and high
current conditions that goes to the
communication board.
Comm vcc failure along with Sensor Critical
Failure can happen in some scenarios while
Download is in progress for switching the
algorithms (Advanced Algorithms to ASME
1989 Algorithms or vice versa, or changing
Fluid types making download of different set
of coefficients)
While the download is in progress flow
equations can momentarily calculate to NaN
value making the device go to Critical
Status. Once the download is complete,
Flow value will calculate to accurate value,
but the device needs power cycle to clear
the latched critical status.
So, Power-cycling after the Configuration
download is completed will clear the Critical
status. Comm vcc that resulted due to this
condition will clear this status as well.
Revision 6.0