Owner's manual

FOUNDATION
TM
Fieldbus Blocks Manual
A-6
The calculation is done by applying the level signal to the IN connector,
the liquid temperature to the IN_1 connector, and the ambient air
temperature to the IN_2 connector. Select the Arithmetic type
(ARITH_TYPE) of Flow Compensation - Linear. This allows a ratio to be
set up that increases the level indication at block output for an increase
in the tank temperature relative to ambient temperature.
Figure A-7. Arithmetic Function Block
Diagram Example
This application can be applied to very large storage tanks whose
contents are subject to thermal expansion and contraction during
seasonal changes in temperature.
Advanced Topics
Arithmetic Types The parameter, ARITH_TYPE, determines how PV and the
compensation terms (t) are combined. User may select from nine (9)
commonly used math functions, depicted below. COMP_HI and
COMP_LO are compensation limits.
• Flow Compensation Linear:
• Flow Compensation Square Root:
TANK_LEVEL
AIR_TEMP
LIQUID_TEMP
IN
IN_1
IN_2
ARTHM
Block
ARITH_TYPE = FLOW
COMP-LINEAR
OUT
FBUS_50A
func PV f•=
f
t(1)
t(2)
---------=
COMP_HI
COMP_LO
func PV f•=
f
t(1) t(3)•
t(2)
-----------------------=
COMP_HI
COMP_LO