Honeywell STT850 Series - ET Tracking Diagnostics; Table 19 - Maximum ET Diagnostics

Revision 4.0 STT850 Series HART/DE Option User’s Manual Page 87
8.2.4 ET Tracking Diagnostics
Table 19 – Maximum ET Diagnostics
Max ET Limit
Parameter
Description
Electronics Temperature (ET) upper
operating limit from specification.
Units are same degree units as has been
selected for SV (Secondary Variable).
Set-up
None.
ET Upper
Limit for
Stress
Condition
Description
Actual limit used in “Time Above Limit” and
“Time Since Last Event”. Value is equal to
“Max ET Limit” less 10% of limits range.
Example
Electronics Temperature range is -40F to
185F for a total of 225F.
“ET Upper Stress Limit”= 185F - 10% of
225F = 162.5F.
Set-up
None – calculation is automatic.
Max ET Value
Parameter
Description
Highest Electronics Temperature ever
experienced by the device.
Units are same degree units as has been
selected for SV (Secondary Variable).
Set-up
None.
NVM
Update every 8 hour.
Time Above
Upper Stress
Limit
Parameter
Description
Accumulation of minutes that device’s
Electronics Temperature has been above
the value of “ET Upper Stress Limit”.
Set-up
None.
NVM
Backup once each 8 hour period
Time Since
Last ET Up
Method
Description
Time that has passed since the last time
device’s Electronics Temperature has
passed above the value of “ET Upper
Stress Limit” (in days, hours and minutes).
Set-up
None.
NVM
Backup once each 8 hour period