Revision 5.0 ST 800 Series HART/DE Option User’s Manual Page 81
Last ET Up
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).
Backup once each 8 hour period
Table 21 – Minimum ET Diagnostics
Electronics Temperature (ET) lower
operating limit from specification.
Units are same degree units as has
been selected for SV (Secondary
Variable).
for Stress
Condition
Actual limit used in “Time Below Limit”
and “Time Since Last Event”. Value is
equal to “Min ET Limit” plus 10% of
Example
Electronics Temperature range is -40°C
to 85°C for a total of 125°C.
“ET Lower Stress Limit” -40°C + 10% of
125°C = -27.5°C.
None – calculation is automatic.
Lowest Electronics Temperature ever
experienced by the device.
Units are same degree units as has
been selected for SV (Secondary
Lower Stress
Limit
Accumulation of minutes that device’s
Electronics Temperature has been
below the value of “ET Lower Stress
Set-up None.
NVM Backup once each 8 hour period
Time Since
Last ET Down
Method Description Time that has passed since the last time
device’s Electronics Temperature has
passed below the value of “ET Lower
Stress Limit” (in days, hours, and
Backup once each 8 hour period