Myron L 729II User Manual

Page 58

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54

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

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