Dwyer ULL - Manual (Page 8)

Configuring 4 mA Current Output
Pr04 function enables you to enter values to be used as the 4 mA mark for remote
monitoring. You can define the 4 mA values for level, distance or flow
measurements (depending on series). The measurement value types should be
defined in Pr04. These definitions will be applicable as well for the 20 mA values
defined in Pr05.
To set 4 mA and 20 mA for level measurements you should configure Pr04 and
Pr05 for level values.
For example, if we measure a tank with tank height configured for 16.4 ft (5.0 m),
the 4 mA values will represent zero tank level and 20 mA values will represent full
tank level. Therefore, the value entered in Pr04 will be 0.0 ft (0.0 m) and the value
entered in Pr05 will be 16.4 ft (5.0 m).
When setting 4 mA and 20 mA for distance measurements, 4 mA values will
represent the minimal distance between the surface of the target and the sensor,
and 20 mA values will represent the maximal distance between the sensor and the
surface of the target. Therefore, 4 mA represents the full part of the tank and 20 mA
represents the empty part of the tank.
NOTE: The values for 4 mA and 20 mA must be different, otherwise an Err (error
message) is displayed.
The values for 4 mA and 20 mA should not be greater than the value used for the
tank height (Pr02). Because of the dead-zone (blind zone), the distance between
the sensor and the surface of the target at its highest level should be a minimum of
0.82 ft (0.25 m) for ULB Standard Range as well as the ULL and ULF Short Range
models. There should be a 1.96 ft (0.6 m) minimum distance for the ULB Extended
Range as well as the ULL and ULF Standard Range models.
The first digit of the 4 mA value can be modified to read between 0 and 5 (feet) for
U.S. Standard Units or between 0 and 1 (meters) metric units (upon request).
After accessing the Pr04 function, the unit generates a fixed current of 22 mA on
the 4 to 20 mA line. When the unit reverts to regular scanning mode, the 4 to 20
mA line returns to regular functioning.
The default measurement values for 4 mA and 20 mA in both the ULB and ULL
models are level.
The default measurement values for 4 mA and 20 mA in ULF Open Channel Series
are flow. When changing from one measurement mode to another, the
measurement units will be changed automatically (for example, when changing
from (F) feet to (M) meters, the units will change from feet to GPM or meters to
M3/H (depending on the model).
The measurement mode selected for the 4 to 20 mA values will not influence the
measurement mode selected for the display (Pr08). In case of power rest,
measurement configuration (level, distance, flow) will be saved according to the
unit's last configuration.
Configuring 20 mA Current Output
The Pr05 function enables you to enter values to be used as the 20 mA mark for
remote monitoring.
To Enter 20 mA Values:
NOTE: The type of measurement (level, distance or flow) selected in Pr04 is also
applicable for Pr05.
The values for 4 mA and 20 mA must be different; otherwise an Err (error message)
is displayed.
The values for 4 mA and 20 mA should not be higher than the value used for the
tank height (Pr02).
The first digit of the 20 mA value can be modified to read between 0 and 5 for U.S.
Standard Units or between 0 and 1 for metric units (model dependent).
After accessing the Pr05 function, the unit generates a fixed current of 22 mA on
the 4 to 20 mA line. When the unit reverts to regular scanning mode, the 4 to 20
mA line returns to regular functioning.
Please refer to Chapter 5 Troubleshooting for 22 mA error indications.
Press/Action Display
For example:
For example:
Explanation
Required menu selection.
Select the format for 4 mA and 20 mA
values to level (L000), distance (d000)
or flow (F000) (depending on model).
Last saved 4 mA level or zero default
value.
Used to enter a new value.
To save the new value, press when
standing on the far right digit. After YES
is displayed, the display returns to the
functions menu.
To return to the main menu without
saving, press when standing on the
far left digit.
or
or
or
Press/Action Display
For example:
Explanation
Required menu selection.
Last saved 20 mA level or default value
(maximum value in range).
Used to enter a new value.
To save the new value, press when
standing on the far right digit. After YES
is displayed, the display returns to the
functions menu.
To return to the main menu without
saving, press when standing on the
far left digit.
or
or
OR
Page 7