Hach Sigma 950, Инструкция по эксплуатации инструмента

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Sensor Installation
sensor. The streamlined shape of the velocity-only sensor allows velocity measurement
in very low-flow conditions. When used in conjunction with a level sensor, the meter can
calculate flow.
6.4.1 Low Profile Velocity-Only (Wafer) Sensor Connection
Note: Use bare-lead sensor and junction box for conduit installation.
The low profile velocity-only sensor connector is located on the right side of the flow meter
(when facing the flow meter) and is labeled Velocity. The connector is keyed and can only
be inserted in the proper orientation (key up). See
Table 14 for pin assignments.
6.4.2 Low Profile Velocity-Only Sensor Programming
1. From the
MAIN MENU
, select
SETUP>MODIFY SELECTED ITEMS.
2. Highlight Velocity Direction using the
UP
and
DOWN
soft keys. Press
SELECT
to
continue.
3. Set the velocity direction (upstream, downstream, or always positive) using the
CHANGE CHOICE
soft key.
4. Press
ACCEPT
to continue.
5. Highlight Velocity Units using the
UP
and
DOWN
soft keys. Press
SELECT
to continue.
6. Set the Velocity Units (fps or m/s), using the
UP
and
DOWN
soft keys. Press
ACCEPT
to continue.
7. Highlight Velocity Cutoff, using the
UP
and
DOWN
soft keys. Press
SELECT
to
continue.
8. Read the Velocity Cutoff information screen. Press any key to continue.
9. Set the Velocity Cutoff using the keypad. Press
ACCEPT
.
10. Set the Velocity Default, using the numeric keypad. Press
ACCEPT
. Press
RETURN
to
go back to the Setup Menu or the Main Menu key to return to the beginning.
6.4.3 Low Profile Velocity-Only Sensor Calibration
No calibration is required for the velocity sensor. The transmit frequency is fixed with a
highly accurate quartz crystal-controlled frequency generator that cannot be adjusted.
6.5 Submerged Depth Only Sensor
The submerged depth only pressure sensor is a pressure transducer that contains a
titanium diaphragm. As the water pressure increases, (with increasing level in the flow
stream) the diaphragm is deflected, or pushed, against a solid state device called a strain
gauge. The strain gauge converts the pressure against the diaphragm to a voltage. As
the level in the flow stream increases, the voltage coming from the submerged pressure
Table 14 Submerged Velocity Sensor Connector Pin Assignments
Pin Signal Description Wire Color
A +12 V dc red
B ground green
C receive (shield) b/w shield
D receive (+) b/w center
E transmit (shield) black shield
F transmit (+) black center