Revision 5.0
ST 800 Series HART/DE Option User’s Manual
Page 77
PV Tracking Diagnostics
Table 15 – Maximum PV Tracking
UTL (Max PV
Limit)
Parameter
Description
Upper Transducer Limit: PV(pressure)
specified upper operating limit in user-
selected units
Set-up
None.
PV Upper
Limit for
Stress
tracking
Method
Description for DP
type
Actual limit value used to note “Time
Above Limit” and “Time Since Last
Event”. “PV Upper Stress Limit” value is
equal to Upper Transducer Limit less
10% of Transducer limits range.
Example for DP
Type
For STD120 span is 0 to 400 inH
2
O.
Range is 400 inH
2
O settable within
LTL = -800 inH
2
O to UTL = 800 inH
2
O
limits.
“PV Upper Stress Limit” =
800 inH
2
O - 160 inH
2
O = 640 inH
2
O.
Example for AP
and GP Types
For STA140 allowable working pressure
is 0 to 500 psia.
Withstand Pressure from LTL = 0 to UTL
= 750 psia.
“PV Upper Stress Limit” = 750 psia – 75
psia = 675 psia.
Set-up
None – calculation is automatic.
Max PV
Parameter
Description
Maximum PV that the device has
experienced in user selected units.
Set-up
None. Value initialized to Min PV Limit
value prior to leaving the factory.
Updates to current PV automatically
when powered at user site after one
minute.
NVM
Update after every 8 hours.
Time Above
Upper Stress
Limit
Parameter
Description
Accumulation of minutes that pressure
measured by the device has been above
“PV Upper Stress Limit”.
Set-up
None – initialized to zero prior to leaving
the factory.
NVM
Backup once each 8 hour period
Time Since
Last PV Up
Method
Description
Time that has passed since the last time
device’s PV passed above “PV Upper
Stress Limit” (in days, hours and
minutes).
Set-up
None – initialized to zero prior to leaving
the factory.
NVM
Backup once each 8 hour period
