Honeywell ST 800 Series - Table 21 - Minimum ET Diagnostics

Revision 5.0 ST 800 Series HART/DE Option User’s Manual Page 81
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
Table 21 – Minimum ET Diagnostics
Min ET Limit
Parameter
Description
Electronics Temperature (ET) lower
operating limit from specification.
Units are same degree units as has
been selected for SV (Secondary
Variable).
Set-up
None.
ET Lower Limit
for Stress
Condition
Description
Actual limit used in “Time Below Limit”
and “Time Since Last Event”. Value is
equal to “Min ET Limit” plus 10% of
limits range.
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.
Set-up
None – calculation is automatic.
Min ET Value
Parameter
Description
Lowest 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 Below
Lower Stress
Limit
Parameter
Description
Accumulation of minutes that device’s
Electronics Temperature has been
below the value of “ET Lower Stress
Limit”.
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
minutes).
Set-up
None.
NVM
Backup once each 8 hour period