Honeywell ST 700 - ST 700 Online Parameterization

Page 154 ST 700 Series HART/DE Option User’s Manual Revision 4.0
Table 40 – Minimum PV Tracking
LTL
(Min PV Limit)
Parameter
Description
Lower Transducer Limit: PV(pressure)
specified lower operating limit in user-
selected units
Set-up
None.
PV Lower Limit
for Stress
Condition
Method
Description
Actual limit value used in “Time Below
Limit” and “Time Since Last Event”.
Value is equal to “Min PV Limit” plus
10% of limits range for DP type
devices and zero for GP and AP type
devices.
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 Lower 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 Lower Stress Limit” = 0 psia.
Set-up
None: calculation is automatic.
Min PV
Parameter
Description
Minimum PV that the device has
experienced in user selected units.
Set-up
None. Value initialized to Max 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 Below
Lower Stress
Limit
Parameter
Description
Accumulation of minutes that pressure
measured by the device has been
below the value of “PV Lower Stress
Limit”.
Set-up
None.
NVM
Backup once each 8 hour period
Time Since
Last PV Down
Method
Description
Time that has passed since the last
time device’s PV passed below the
value of “PV Lower 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