Owner's manual

4
CALIBRATION
Adjusting ZERO and SPAN
The following adjustments apply to both the
4-20 mA and 0-5 V outputs. The factory rec-
ommends when using 0-5 V signal, do not
go below 1 V or above 4 V as output signal
in the linear range.
Before initial adjustments, set both trimpots
to their maximum position by turning each
control clockwise twenty (20) turns. The
control’s internal clutch will click quietly at
the end position.
To adjust Zero reading, start fluid flow at its
lowest anticipated flowrate within the linear
flow range of the turbine. Then turn the
ZERO trimpot counterclockwise until the
indicated reading begins to rise from 4 mA
(or 1 V). Then turn back to the 4 mA (or 1 V)
reading. This is the true ZERO read. Any
flowrate below this “threshold,” including no
flow, will produce a 4 mA (or 1 V) reading.
To adjust SPAN, start the fluid flow to its
highest anticipated flowrate within the lin-
ear flow range of the turbine. Then, turn the
SPAN trimpot counterclockwise until the in-
dicator just drops to 20 mA (or 4 V). Any
flowrate above this will produce an indica-
tion higher than 20 mA (or 4 V).
Usually, no further adjustment will be re-
quired. However, if “fine tuning” is required,
note that adjustments in ZERO trimpot will
require adjustments in SPAN. the converse
is not true, adjusting the SPAN setting will
have little or no effect on the ZERO setting.