Myron L 729II - Manual (Page 58)

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C. SETUP PROCEDURES
These Setup procedures cover (1) converting the alarm circuit to
trigger on a decreasing (conductivity) or increasing (Resistivity)
reading, (2) checking out your new Monitor/controller, (3)
setting the alarm circuit setpoint(s), and (4) adjusting the
hysteresis.
The following require that the front panel be removed. While do-
ing so be careful not to strain the cable(s).
NOTE: A small screwdriver or tweaker will be required for sev-
eral of the following operations.
1. SET POINT CONVERSION (SPC) /
REVERSING SET POINT
The alarm/control circuit(s) on all 750 Series II Conductivity/
TDS Monitor/controllers are configured to trigger the alarm relay
as the conductivity/TDS reading increases.
NOTE: The reverse is true for Resistivity Monitor/controllers
which are configured to trigger on decreasing.
If the user’s application requires it, the alarm circuit may be
easily reconfigured to trigger the alarm relay as the conductivity
(or ppm) reading decreases or increases for Resistivity. Refer
to figure V.A.1. for the locations of the jumpers referred to in this
section.
NOTE: These instructions describe the general procedures for
converting the Monitor/controller without reference to jumper
numbers or orientation.
1. Ensure power is OFF.
2. Locate the jumper block for the alarm to be configured.
3. Make a note of the current orientation of the jumpers.
4. Remove both jumpers. This is easily done by hand.
Take care not to crush the jumpers if using pliers.
5. Rotate the jumpers 1/4 turn and reinstall them on their
posts as shown in figure IV.C.1.
2. CHECK-OUT PROCEDURES
The following check-out procedures are used to verify that the
750 Series II Monitor/controller is operating properly. It is as-
sumed that the Monitor/controller power is ON, that it is con-
nected to a CS51 or appropriate Sensor, and that the Sensor is
immersed in water within the range that the Monitor/controller
will be required to read. Refer to figure V.A.1. for the locations of
the components referred to in this section.
1. Make a note of the reading on the display.
2. Being careful not to strain the connecting cable(s),
unfasten and remove the front panel.
3. While pressing the Calibration/Full Scale Test Switch
(FS SW), verify that the front panel display is indicating
a full scale reading. If not, see Calibration, section V.C.
4. Press and hold the “SET POINT” switch on the front
panel. Using a tweaker or a small screwdriver, adjust
the Set Point trimmer adjustment screw on the circuit
board to sweep the display from zero to full scale. (A
digital display may be blank at the full scale end. This
is normal.) Listen for the alarm relay to click ‘ON and
OFF’ as the alarm set point moves past the water
reading.
5. Adjust the alarm to the desired set point value. Release
the “SET POINT” switch.
NOTE: For Models with SC/SCO module, repeat STEPS 4 & 5
to check out Set Point #2.
3. SET POINT ADJUSTMENT
The set point setting is based upon the user’s particular water
purity specifications or requirements.
NOTE: The optional second relay/alarm is “stacked” on the first
relay/alarm, therefore, when setting the optional second relay/
alarm Set Point, the #1 Set Point must be ‘set’ first.
1. Being careful not to strain the cable, unfasten and
remove the Monitor’s front panel.
2. While depressing the “SET POINT” switch, turn
the Set Point #1 adjustment screw (See figure V.A.1)
until the desired set point value is indicated on the
display.
3. If Hysteresis adjustment is required see below. If not,
reinstall the front panel and tightly secure both
retaining screws.
4. HYSTERESIS (DEAD BAND) ADJUSTMENT
The hysteresis or dead band is approximately ±3% of the set
point at full scale as it leaves the factory. Under normal (most)
conditions it will not be necessary to adjust.
However, if you desire to make an adjustment please keep the
following in mind.
The adjustment is very simple and is based on set point loca-
tion. If the set point* is in the upper 75-100% of the scale, the
hysteresis control pot should be turned fully to the right.
If the set point is in the lower portion of the scale, i.e. 5-25% of
scale, the control pot may be turned fully to the left.
If you are operating in the center, 25-75% of scale, the control
pot may be adjusted in the center.
Or the hysteresis or dead band may be adjusted to tighten the
control of a particular process.
!
CAUTION - READ FOLLOWING CAREFULLY
JUMPER CONVERSION
Figure IV.C.1
INCREASING DECREASING
CONDUCTIVITY/TDS
DECREASING INCREASING
RESISTIVITY