Myron L 729II User Manual
Page 4
3. 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.
4. Adjust the alarm to the desired set point value. Release
the “SET POINT” switch.
NOTE: For Models with SC/SCO module, repeat STEPS 3 & 4 to
check out Set Point #2.
QUICK SET POINT ADJUSTMENT -
See Section IV.C.3.
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. While pressing 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.
HYSTERESIS (DEAD BAND) ADJUSTMENT -
See Section IV.C.4.
PRIMARY COMPONENT IDENTIFICATION -
Section V.A.
Review the figure below to familiarize yourself with the Main
circuit board assembly. The diagram has the second
alarm/control module option installed.
QUICK CALIBRATION - Section V.C.
WARNING: When performing calibration procedures,
the technician must take extreme care to avoid
contacting the circuitry other than the CALibration
control. Failure to do so could result in damage to
the equipment, property and/or personal injury.
The following assumes the front panel has been
removed and the power is ON.
ELECTRONIC CALIBRATION (CIRCUIT ONLY) -
See Section V.C.1.
ZERO Adjustment
1. Press and hold the ZERO Test switch. The display should
indicate 7 pH or 0 mV selected. If not, set to 7 pH or 0 mV
with the ZERO CALibration control.
2. Turn power OFF.
3. Re-install front panel as described in “REASSEMBLY”.
4. To operate, turn power ON.
0-10VDC Recorder Calibration - See Section V.C.2.
Using Standard Solutions - Section V.C.3.
The BEST method of verifying and recalibrating your pH or ORP
Monitor/controller is with NIST traceable Standard Solution
(available from the Myron L Company). Because it includes the
sensor, the entire system is recalibrated.
NOTE: Another means of verification or calibration of pH or ORP
models is to use the transfer standard method, using a hand-held
or portable instrument capable of these measurements, i.e. the
Myron L Ultrameter™. See section V.C.4 for description.
The following procedure describes the easiest method for
standard solution calibration of your Monitor/controller.
1. Using 7pH buffer solution rinse a clean glass beaker
thoroughly with the buffer solution.
2. Place sensor in the beaker of buffer solution. Level of
buffer solution should be high enough to cover at least 1”
above the sensor lower end.
3. Carefully shake the sensor to remove air bubbles from
inside the sensor bore hole.
4. Allow 5-10 minutes for temperature to equilibrate. For the
quickest and the best results, both the sensor and
solution should be at the same temperature.
5. Read the panel meter/display. The display should match
the value and units of measure located on the bottle of
buffer solution. If the reading is different, adjust ZERO
calibration control on the main control circuit board
until the reading is 7pH or 0mV.
6. Repeat steps 2 - 5 using either 4 or 10 pH buffer
solution.
7. If reading is incorrect, adjust SPAN calibration
control on the main control circuit board until reading
matches buffer solution.
8. After adjustment, turn power OFF.
9. Re-install front panel as described in “REASSEMBLY”.
10. To operate, turn power ON.
SENSOR SUBSTITUTE CALIBRATION -
See Section V.C.4.
TRANSFER STANDARD METHOD - See Section V.C.5.
21 may 03
{
POWER
AC LINE/ +DC
AC NEUTRAL/ -DC
GROUND
Figure V.A.1
SPAN
ZERO
DO NOT
ADJUST
RELAY #1
}
COM
NC
NO
3SO/3SE
SWITCH
CONNECTION
DISPLAY/METER
CONNECTOR
4-20 CONNECTOR
SET POINT #1
CONVERSION
TRANSFORMER
FUSE*
115/
230
ZERO
CALIBRATION
CONTROL
SET POINT #2 CONTROL
SC/SCO
OPTIONAL
SECOND
ALARM/
CONTROL
MODULE
SET POINT #2
CONVERSION
#2 RELAY
LIGHTS &
SWITCH
CONNECTOR
DISPLAY CALIBRATION
CONTROL (FACTORY SET)
RUBBER TAPE
(DO NOT
REMOVE)
SPC
INC
PA
SET POINT
#1 CONTROL
INC
SET POINT #1
HYSTERESIS
RIGHT INC
LEFT DEC
CHASSIS GROUND - OEM
INC
SET POINT #2 HYSTERESIS
RIGHT INC / LEFT DEC
3S
SPC
0-10VDC OUTPUT
B
L
K
W
H
T
R
E
D
G
R
N
N
E
U
(+)
SENSOR
(-)
+
COM
RELAY #2
}
NO
NC
+
SPAN (GAIN)
CALIBRATION
CONTROL
721 726
722 727
723 728
724 729
MYRON L
COMPANY
7 pH/ZERO mV
PUSH TO TEST
SPAN (GAIN/SLOPE)
PUSH TO TEST
CONFIGURATION
MODULE
CONFIGURATION
MODULE
ALIGNMENT
ORP ZERO CALIBRATION
CONTROL (FACTORY SET)
SOLID STATE (24VDC 30mW)
OUTPUT
PA™ PIEZO ELECTRIC ALARM
OR
RA™ REMOTE ALARM OR
CUSTOMER CONNECTION
SOLID STATE (24VDC 30mW)
OUTPUT
PA™ PIEZO ELECTRIC ALARM
OR
RA™ REMOTE ALARM OR
CUSTOMER CONNECTION
HYS1
SP1
ZERO
DIS
ORP ZERO
UP
BK WT RD GN NU R- R+
PWR
C GD NC NO CM
FLOW SWITCH
RA
PA
CM
N
O
N
C
DE
C
pH
CH
S
SP
AN
GN
D
REMOVE T
O INST
ALL
SECOND RELA
Y
}