Worst case delay time to acquire level data from all tank gauges in system (assumes one temperature poll
from gauge with longest temperature delay time).
2.(T1L)x(A1) + (T2L)x(A2) + (TnL)x(An) + (TwT)
Where:
T1L = Tank gauge #1 level delay time (based on selected level resolution)
T2L = Tank gauge #2 level delay time (based on selected level resolution)
TnL = Tank gauge #n level delay time (based on selected level resolution)
A1 = Number of level averages for tank gauge #1
A2 = Number of level averages for tank gauge #2
An = Number of level averages for tank gauge #n
TwT = Temperature delay time of tank gauge with most RTDs
(i.e., longest time delay (based on selected temperature resolution)
Example Calculations.
What is the expected overall system delay time for a 4 tank gauge system with the following programma-
ble parameter settings:
Tank Gauge #1 Tank Gauge #2
- model D8 - model D9
- 1 float - 2 floats
- Level averages = 1 - Level averages = 1
- Level resolution = 0.001 inches - Level resolution = 0.01 inches
- Temperature enabled/LOW resolution - Temperature disabled
(gauge w/5 RTDs)
Tank Gauge #3 Tank Gauge #4
- model LD - model LD
- 1 float - 2 floats
- Level averages = 3 - Level averages = 1
- Level resolution = 0.01 inches - Level resolution = 0.1 inches
- Temperature disabled - Temperature enabled/LOW resolution
(gauge has 2 RTDs)
The overall system delay time equation becomes,
(T1L)x(A1)x(NT)x(5) + (T1T) + (T2L)x(A2)x(NT)x(5) + (T2T) + (T3L)x(A3)x(NT)x(5) + (T3T) +
(T4L)x(A4)x(NT)x(5) + (T4T)
Substituting each variable with the respective values the equation becomes,
(1.32)x(1)x(2)x(5) + (5.5) + (0.65)x(1)x(2)x(5) + (0) +
(0.73)x(3)x(2)x(5) + (0) + (0.58)x(1)x(2)x(5) + (1.9)
Overall system delay time to update level and temperature on all 4 gauges = 54.8 seconds.
What is the expected worst case delay time to acquire level data from the above described 4 tank gauge
system (assumes one temperature poll from gauge with longest temperature delay time).
The worst case delay time equation for level data from all gauges in the system becomes,
NOTE
TwT = 0 seconds if all temperature polling is disabled.
93
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