IM 01C25R03-01E
6-2
6. EXPLANATION OF BASIC ITEMS
6.3.2 Block Mode
The Block modes permitted for the SENSOR transducer
block are Automatic (Auto) and Out of Service (O/S).
The mode must be set to Auto under normal operating
conditions, and to O/S when making changes to an
important parameter. For parameters that can only be
changed in the Auto and O/S modes, refer to the param-
eter list for the SENSOR Transducer block in Chapter 9.
6.3.3 Functions Relating to Differential
Pressure
Reference to differential pressure value:
By accessing PRIMARY_VALUE, it is possible to refer
to the differential pressure value and status. The update
period of this value is 100 msec. The pressure unit is
selected by XD_SCALE.unit of the AI block, in which
PRIMARY_VALUE is selected. The status is normally
Good-Non Specific. However, in the case of a sensor
failure or out of measurement range, it turns to Bad or
Uncertain. For details, refer to Table 8.9.
Setting of signal damping for differential pressure:
When the differential pressure signal fluctuates greatly,
the fluctuation can be reduced by increasing the time
constant for signal damping.
PRIMARY_VALUE_FTIME is the parameter for
setting the signal damping for differential pressure. The
unit of signal damping is second.
Determination of the range limit of differential
pressure signal:
When the differential pressure signal deviates more
than 10% from the capsule measurement range shown
in PRIMARY_VALUE_RANGE, set the status of
PRIMARY_VALUE to Uncertain-Sensor Conversion
not Accurate.
Adjustment of pressure/differential pressure signal:
EJX910A Multivariable Transmitter have been accu-
rately adjusted according to the specifications at
factory setting. Minimal errors can occur due to the
environment where the transmitter is installed and the
mounting position. To fine-tune any errors, three zero/
span adjustment functions can be used: automatic and
manual zero/span adjustment by communication
terminals, and zero-point adjustment by means of the
external adjustment screw on the transmitter.
Automatic adjustment
The value of the pressure exerted on the point where
the adjustment is to be made is assigned to parameters
(CAL_POINT_LO, CAL_POINT_HI). After this
assignment is set, the amount of adjustment is calcu-
lated by the transmitter and automatically updated.
Manual adjustment
From the exerted pressure and the output of the
transmitter, calculate the amount of zero/span adjust-
ment manually, and assign the calculated value to
parameters (CAL_DEVIATION_LO,
CAL_DEVIATION_HI).
F0601.EPS
PRIMARY_VALUE
(Channel1)
Sensor
signals
SECONDARY_VALUE
(Channel2)
TERTIARY_VALUE
(Channel3)
CAP_TEMP_VAL
(Channel6)
Pressure
/differential
pressure
calculation
Static
pressure
calculation
Historical
records
Equipment
information
Range
check
Range
check
Simulation
value
Adjust-
ment
Simulation
value
Adjust-
ment
Range
check
Damping
processing
Damping
processing
Damping
processing
Unit
Check
Unit
Check
H-side
static
pressure
L-side
static
pressure
Unit
Check
Capsule
temperature
calculation
EXT_TEMP_VAL
(Channel4)
Range
check
Adjust-
ment
Simulation
value
Unit
check
External
temperature
calculation
AMP_TEMP_VAL
(Channel7)
Range
check
Unit
Check
Amplifier
temperature
calculation
RTD
signals
Figure 6.2 SENSOR Transducer Functional Block
