Vzor MAPK-902 User manual

MAPK-902
pH-METER
Operation Manual
Nizhny Novgorod
2010
АЯ 74

2
VZOR Ltd. will be grateful for any proposals and criticisms
helping improve the product.
If you have any trouble using the instrument please contact us
in writing or by phone.
Mailing address 603106 Nizhny Novgorod, P.O.B. 253
Telephone/fax [phone]
412-29-40, 412-39-53
E-mail: [e-mail]
http: www.vzornn.com

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C O N T E N T S
1 DESCRIPTION AND OPERATION ....................................................................... 4
1.1 Purpose ........................................................................................................... 4
1.2 Basic parameters and dimensions .................................................................. 5
1.3 Specifications .................................................................................................. 8
1.4 Product components ..................................................................................... 10
1.5 Design and operation .................................................................................... 10
1.6 Measuring instruments, tools and accessories ............................................. 25
2 INTENDED USE .................................................................................................. 26
2.1 Operating limitations ...................................................................................... 26
2.2 Safety precautions ......................................................................................... 26
2.3 pH-meter setting-up procedures.................................................................... 27
2.4 Measurements ............................................................................................... 42
2.5 Troubleshooting ............................................................................................. 43
3 MAINTENANCE ................................................................................................... 45
3.1 pH-meter scheduled maintenance ................................................................ 45
3.2 Replacement of PU-902LD probe unit combination electrode ...................... 45
4 DELIVERY SET ................................................................................................... 48
APPENDIX A. pH of standard buffer solutions versus temperature ....................... 49
APPENDIX B. pH of highly dilute alkaline and acid solutions as
a function of the analyte medium temperature, computed using
the data from MU 34-70-114-85 Guidelines ........................................................... 50
APPENDIX C. Protocol of data communications with PC ...................................... 51

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1 DESCRIPTION AND OPERATION
1.1 Purpose
1.1.1 Product name and identification
рН-meter with a panel-mounted converting unit and the PU-902 probe unit:
MAPK-902 рН-meter. TU 4215-024-39232169-2006 Specifications.
рН-meter with a wall-mounted converting unit and the PU-902 probe unit:
MAPK-902/1 рН-meter. TU 4215-024-39232169-2006 Specifications.
рН-meter with a panel-mounted converting unit and the PU-902A probe unit:
MAPK-902A рН-meter. TU 4215-024-39232169-2006 Specifications.
рН-meter with a wall-mounted converting unit and the PU-902A probe unit:
MAPK-902A/1 рН-meter. TU 4215-024-39232169-2006 Specifications.
рН-meter with a panel-mounted converting unit and the PU-902LD probe
unit:
MAPK-902LD рН-meter. TU 4215-024-39232169-2006 Specifications.
рН-meter with a wall-mounted converting unit and the PU-902LD probe unit:
MAPK-902LD/1 рН-meter. TU 4215-024-39232169-2006 Specifications.
1.1.2 The рН-meter is designed for continuous measuring of hydrogen ion
activity index (pH) and aqueous solution temperature.
1.1.3 MAPK-902 and MAPK-902/1 рН-meters are intended to measure hy-
drogen ion activity index (pH) in thermal power industry and various industries.
MAPK-902А, MAPK-902А/1, MAPK-902LD, MAPK-902LD/1 рН-meters are
intended to measure hydrogen ion activity index (pH) in wastewater and for envi-
ronmental uses.
1.1.4 Converter type:
 operating with a sensitive element to measure hydrogen ion activity index
(pH);
 with galvanic input/output separation;
 with indication device;
 with two measuring channels;
 as units for panel or wall installation;
 with current output and RS-485 port measuring data displayed.
1.1.5 Sensitive element type − in accordance with Table 1.1.

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Table 1.1
рН-meter
version
ЭС-10601/7
glass
electrode
ЭСр-10106-3.0
reference
electrode
ЭСК-10617/7
combined
glass
electrode
Sensitive
element version
MAPK-902
MAPK -902/1 + + −
flow-through/dip
MAPK -902А
MAPK -902А1 − − +
MAPK -902МP
MAPK-902МP/1
− − + line-dip (LD)
1.1.6 This рН-meter version incorporates an electronic preamplifier
galvanically isolated from the converter and located next to the electrodes to in-
crease the allowable distance between the converter and the electrode system.
1.2 Basic parameters and dimensions
1.2.1 By resistance to climatic effects the рН-meter falls within Version
Group В4 as per GOST 12997-84.
1.2.2 By resistance to mechanical effects the рН-meter falls within Version
Group L1 as per GOST 12997-84.
1.2.3 By protection against environmental exposure, the рН-meter’s compo-
nents meet GOST 14254-96 in accordance with Table 1.2, depending on its ver-
sion.
Table 1.2
рН-meter version Description and identification of units Unit versions as per
GOST 14254
MAPK-902
MAPK-902А
MAPK-902LD
Converting unit ВР31.01.000
(panel-mounted version)
IP30
MAPK-902/1
MAPK-902А/1
МАРК-902LD/1
Converting unit ВР43.01.000
(wall-mounted version)
IP65
MAPK-902
MAPK-902/1
MAPK-902А
MAPK-902А/1
Amplifier unit ВР31.02.100 IP62
MAPK-902LD
MAPK-902LD/1
PU-902LD probe unit ВР43.02.000 IP68

6
1.2.4 By resistance to atmospheric pressure this pH-meter version falls
within Р1 Group as per GOST 12997-84 (atmospheric pressure from 84 to
106.7 kPa).
1.2.5 Analyte medium parameters
1.2.5.1 Analyte medium (aqueous solutions) temperature, С ….. + 5 to + 50.
1.2.5.2 Analyte medium pressure for MAPK-902А, MAPK-902А/1,
MAPK-902LD, MAPK-902LD/1, MPа …………………………………........ 0 to 0.025.
1.2.6 Operating conditions
1.2.6.1 Ambient air temperature, С ……………………………….. + 5 to + 50.
1.2.6.2 Ambient air relative humidity at 35С and lower temperatures without
moisture condensation, %, max …....................................................................... 80.
1.2.6.3 Atmospheric pressure, kPa (mm Hg) ….... 84.0 to 106.7 (630 to 800).
1.2.7 The pH-meter is powered from single-phase 220 V AC (50 ± 1) Hz
mains.
The supply voltage tolerance varies from –15 to +10 %.
Power consumption, V∙A, max ……..…………….…………........................ 10.
1.2.8 The pH-meter provides operation with electrode systems whose EMF
corresponds to the following equation:
)(ΕΕ iti pHpHS



, (1.1)
where Е  electrode system EMF, mV;
Еi, pHi  coordinates of the electrode system isopotential point, mV,
рН;
pH  hydrogen ion activity, pH;
St  electrode system transconductance, mV/pH.
The St value is defined with the following expression:
CstSt





)16.273(1984.0 , (1.2)
where t – analyte medium temperature, С;
Cs  coefficient taking values from 0.8 to 1.01 and used to allow for
the deviation of electrode system transconductance from a theoretical value for
which Cs=1.
1.2.9 The pH-meter electrode system may be set to the parameters shown in
Table 1.3.
Table1.3
Slope of electrode system hydrogen
curve in the linear part thereof,
mV/pH, min
Coordinates of electrode system
isopotential point
Е
i
, mV pH
i
, рН
− 57.0 (at 20 С) −14 ± 54 7.0  0.3
1.2.10 Overall dimensions and weights of the main pH-meter components
are shown in Table 1.4.

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Table1.4
pH-meter
version
Component name and identification Overall
dimensions,
mm, max
Weight
,
kg,
max
MAPK-902
MAPK-902А
MAPK-902LD
Converting unit ВР31.01.000
252146100
2.60
MAPK-902/1
MAPK-902А/1
MAPK-902LD/1
Converting unit ВР43.01.000
26617095
2.60
MAPK-902 PU-902 probe unit ВР31.02.000:
MAPK-902/1

ВР31.02.100 amplifier unit; 120

83

30 0.3

ВР31.02.200 temperature sensor;

11

128 0.05

ЭС-10601/7 glass electrode;

12

170 0.07

ЭСр-10106-3.0 reference electrode

10/26

230
0.10
MAPK-902А PU-902А probe unit ВР31.02.000-01:
MAPK-902А/1

ВР31.02.100 amplifier unit; 120

83

30 0.3

ВР31.02.200 temperature sensor;

11

128 0.05

ЭСК-10617/7 combination glass
electrode.

12

160 0.10
MAPK-902LD
MAPK-902LD/1
PU-902LD probe unit ВР43.02.000

60

260 1.55
1.2.11 Conditions for the pH-meter transportation in shipping crates as per
GOST 12997:
 temperature, С ..........…..………………….………………….... − 5 to + 55;
 relative humidity at 25 С, %, max ………………………………………. 95;
 sinusoidal vibration at 5-35 Hz, shift amplitude of 0.35 mm in the direction
shown by the "THIS WAY UP. HANDLE WITH CARE" sign on a crate.
1.2.12 Reliability requirements:
 average time between failures (except for electrodes), hours,
min…………………………………………………………………………............ 20.000;
 mean recovery time, hours, max …………………………………………… 2;
 pH-meter average life (with electrodes replaced), years, min ………… 10.
1.2.13 Electric resistance of the pH-meter supply circuit insulation between
plug pins and frame, M, min:
 at ambient air temperature of (20  5) С …………….…………………. 40;
 at ambient air temperature of 50 С …….……...………………………… 10;
 at ambient air temperature of 35 С and relative humidity of 80 %...…... 5.
1.2.14 Electric insulation of the pH-meter power supply circuit relative to the
converting unit case withstands for 1 min a 1.5 kV 50 Hz AC test sinusoidal voltage
at an ambient air temperature of (20 ± 5) С and relative humidity from 30 to 80 %.
1.2.15 Electric resistance between the external terminal (contact) of the con-
verting unit protective earthing and frame, , max ……………………………. 0.1.

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1.3 Specifications
1.3.1 pH-meter’s hydrogen-ion activity index measurements, рН …... 1 to 12.
1.3.2 The pH-meter’s margin of allowable basic absolute measuring error for
pH measurements at an analyte medium temperature of (25.0 ± 0.2) С and ambi-
ent air temperature of (20 ± 5) С, pH:
 for MAPK-902 and MAPK-902/1 versions …….……………....……. ± 0.05;
 for MAPK-902А, MAPK-902А/1, MAPK-902MP and MAPK-902MP/1 ver-
sions ……………………………………………………….……........................... ± 0.20.
1.3.3 The pH-meter’s margin of allowable complementary absolute measur-
ing error for pH caused by a change in the analyte medium temperature (tempera-
ture compensation error), рН:
 for MAPK-902 and MAPK-902/1 versions ……….……….…....…….. ± 0.1;
 for MAPK-902А, MAPK-902А/1, MAPK-902MP and MAPK-902MP/1 ver-
sions ……………………………………………..………..……........................... ± 0.20.
1.3.4 Margins of allowable complementary absolute error of the MAPK-902А,
MAPK-902А/1, MAPK-902MP and MAPK-902MP/1 pH-meter versions in measur-
ing рН caused by a change in the analyte medium pressure, ranging from 0 to
0.025 MPa, рН ….............................................................................................. ± 0.1.
1.3.5 Analyte medium temperature measuring range, °С ………...+ 5 to + 50.
1.3.6 Margins of the pH-meter’s allowable basic absolute error in measuring
the analyte medium temperature at an ambient air temperature of (20 ± 5) С,
С…………………………………………………………………………………….. ± 0.3.
1.3.7 Converter measuring range:
 at рН measurements, рН …...………………………………………... 0 to 15.
 at U measurements (for MAPK-902, MAPK-902/1, MAPK-902А and
MAPK-902А/1 versions), mV ……………………………………… − 1.000 to + 1.000.
1.3.8 Margins of the converter’s allowable basic absolute error at an analyte
medium temperature of (25.0 ± 0.2) С and ambient air temperature of (20 ± 5) С:
– at рН measurements, pH ………………………………….…………. ± 0.02;
– at U measurements (for MAPK-902, MAPK-902/1, MAPK-902А and
MAPK-902А/1 versions), mV …………………………………………..……………. ±2.
1.3.9 Margins of the converter’s allowable complementary absolute error
caused by a change in the analyte medium temperature (temperature compensa-
tion error), рН …………………………………………………………………….. ± 0.03.
1.3.10 Temperature compensation range at рН measurements,
С……………………………………………………..…………………. from +5 to + 50.
1.3.11 Margins of the converter’s allowable complementary absolute error
caused by deviation of ambient air temperature from the normal one (20 ± 5) С
per each ± 10 С within an operating temperature range from + 5 to +50С:
– at рН measurements, pH ……………………………………………... ± 0.01;
– at U measurements (for MAPK-902, MAPK-902/1, MAPK-902А and
MAPK-902А/1 versions), mV ………..………………………………….…………… ± 1.

9
1.3.12 Margins of the allowable complementary absolute error caused by re-
sistance effect in the measuring electrode circuit per each 500 M within a meas-
uring range from 0 to 1.000 M:
– at рН measurements, pH …………………….…………….……….. ± 0.005;
– at U measurements (for MAPK-902, MAPK-902/1, MAPK-902А and
MAPK-902А/1 versions), mV ………..…..…………………………..…............... ± 0.5.
1.3.13 The converter (for MAPK-902, MAPK-902/1, MAPK-902А and MAPK-
902А/1 versions) withstands an input signal load for 2 h, mV ………… ± 1.250.
1.3.14 Margins of the pH-meter’s allowable complementary absolute error
caused by deviation of ambient air temperature from the normal one (20 ± 5) С
per each ± 10 С within an operating temperature range from +5 to +50 С,
°С…....……….................................................................................................... ± 0.1.
1.3.15 Converter reading stability at a minimum continuous operating time of
24 h, рН, at least ……………..…………………………………………………… ± 0.02.
1.3.16 Measured pH value-to-output current conversion function at an ambi-
ent air temperature of (20 ± 5) С is as follows:
 for 4-20 mА current output at load not exceeding 500 :
range
init
output mАI Χ
ΧΧ
164)(

 , (1.3)
 for 0-5 mА current output at load not exceeding 2 k:
range
init
output mАI Χ
ΧΧ
5)(

 , (1.4)
where X – measured рН value;
Xinit – рН measuring subrange starting value (for current output);
Xrange – рН measuring subrange width (for current output) defined as a
difference between the рН measuring subrange minimum and maximum (for cur-
rent output).
1.3.17 Margins of the allowable basic reduced error in converting the meas-
ured рН value into output current at an ambient air temperature of (20 ± 5) С, % of
the current output range:
 0-5 mA……………………………………………………………............ ± 0.5;
 4-20 mA…………………………………………………………………… ± 0.5.
1.3.18 Margins of the allowable complementary reduced error in converting
the measured рН value into output current, caused by caused by deviation of am-
bient air temperature from the normal one (20 ± 5) С per each ± 10 С within an
operating temperature range from +5 to +50 С, % of the current output
range………………………………………..………………………………………. ± 0.25.
1.3.19 Converter’s output signal (reading) settling time, s, maximum …… 10.
1.3.20 рН-meter’s output signal (reading) settling time, min, maximum … 15.
1.3.21 Converter’s warm-up and heat balance settling time, h, max ……. 0.5.
1.3.22 If the measured рН or U value (for MAPK-902 and MAPK-902/1 ver-
sions) or temperature goes beyond range limits, the audible alarm goes off and the
OVERLOAD indicator lights up on the рН-meter face panel. The OVERLOAD! sign
is displayed on the рН-meter screen.

10
1.3.23 Any excess by the measured рН or U value (for MAPK-902 and
MAPK-902/1 versions) of the threshold limits will cause the or symbol to ap-
pear on the рН-meter indicator screen and the threshold relay to operate.
1.3.24 When connected to a personal computer (PC), the рН-meter ex-
changes information with PC through the RS-485 interface.
1.4 Product components
1.4.1 The product is comprised of the following components:
 panel- or wall-mounted converting unit depending on the рН-meter ver-
sion;
 PU-902, PU-902А or PU-902LD probe unit depending on the рН-meter
version (one or two depending on the delivery set);
 cable for connecting the probe unit to a converting unit (one or two de-
pending on the delivery set);
 mounting parts kit.
1.5 Design and operation
1.5.1 pH-meter general data
The рН-meter is a dual-channel measuring instrument designed for continu-
ous measuring:
 hydrogen ion activity (pH) within a range from 1 to 12 рН;
 temperature of aqueous solutions within a range from +5 to +50 С;
 U (MAPK-902, MAPK-902/1, MAPK-902А and MAPK-902А/1 рН-meter
versions) within a range from – 1.000 to +1.000 mV.
Measured рН and analyte medium temperature values are displayed on the
screen of a digital LCD display (“the display”) with the least significant digit 0.001 pH
(pH measurements), 1 mV (U measurements) and 0.1 С (temperature measure-
ments). It provides separate or simultaneous indication for two measuring chan-
nels.
For convenient recording of measured pH values on a recording unit using
current outputs, the рН-meter’s user may set the pH measuring subrange start and
end values (by current output).
Each pH measuring channel of the pH-meter has a current output with uni-
fied output DC signals from 0 to 5 mA or from 4 to 20 mA. A unified output DC sig-

11
nal (from 0 to 5 mA or from 4 to 20 mA) may be set separately for each channel.
The lower (0 or 4 mA) and upper (5 or 20 mA) limits of a current output range cor-
respond to the programmed pH measuring subrange start and end values (by cur-
rent output).
Apart from unified output DC signals from 0 to 5 mA or from 4 to 20 mA, the
рН-meter’s user may set a unified output DC signal from 0 to 20 mA for each
channel, using the рН-meter menu.
pH measuring subranges in each channel may be selected independently.
Values of selected subranges limits are also displayed. In case any of the
subranges is overloaded the OVERLOAD! indication will appear on the display
screen.
The probe unit is connected to the converting unit with a cable 5 to 100 m
long.
Each of the рН-meter channels has two freely programmable thresholds set-
ting the upper and lower limits for monitoring the measured pH value. If pH values
go beyond the threshold limits the relay’s dry contacts will close and the character
of the upper or lower threshold limit will be displayed.
In accordance with MU 34-70-114-85 Guidelines, the рН-meter may reduce
the measured рНt value to рН25.
рН values are reduced to рН25 within a range from +5 to +50 С. A reduced
рН25 value may be shown on the display.
The pH-meter’s function showing the dependence of the рН value of highly
diluted acid and alkali solutions on the analyte medium temperature is charted in
Appendix B.
1.5.2 pH-meter operating principle
The pH-meter operation is based on the potentiometric method for analyte
solution pH measurement.
The electrode system immersed in an analyte solution generates U linearly
dependent on the pH value.
Signals (U) from the electrode system and temperature sensor are supplied
to the converter comprised of the amplifier and converting units. Once amplified
and digitized in the amplifier unit, signals are then fed to the converting unit input
via cable.
The measured U of the pH-meter electrode system is translated into the pH
value, allowing for the analyte solution temperature, i.e. temperature compensation
occurs automatically and only relates to the electrode system U variations.

12
1.5.3 pH-meter components
1.5.3.1 Converting unit
The converting unit is a microprocessor instrument designed to display
measuring results (рН, рН25, U and temperature), generate a current output signal,
control the threshold relay and exchange with a PC. The unit is powered from sin-
gle-phase 220 V AC 50 Hz mains. The converting unit may be panel- or wall-
mounted.
The layout of indicators and controls on the converting unit face panel (pan-
el- and wall-mounted versions) is shown in Fig.1.1:
Figure 1.1 − Layout of indicators and controls on the converting unit face panel
 display screen designed to show measured рН, рН25, U and temperature
values and pH-meter operating modes;
 “POWER” button to switch the pH-meter on and off;
 “” and “” buttons to move the cursor up and down the menu when se-
lecting the operating mode and changing measuring subranges (by current output)
and threshold values;
 “CHANNEL” button to change channel indications and menus;
 “
enter
menu ” to enter the menu and confirm the values and operating modes
selected in programming;
рН-meter
MAPK
902
Range
1.1 − 10.1
рН 4.011
24.3

С
А
OVERLOAD
POWER
1
0
MENU
ENTER
CHA
N
NEL

13
 button “ ” to switch on and off the display screen illumination;
 “OVERLOAD” red LED indicator to show an overloaded range for current
output, temperature and U;
 “POWER” green LED power on indicator.
The panel-mounted CU rear panel (see Fig.1.2) and the wall-mounted CU
lower panel (see Fig.1.3) feature the following components:
Figure 1.2 − Layout of connectors on the panel-mounted converting unit rear panel
Figure 1.3 − Layout of connectors on the wall-mounted converting unit lower
panel
~220 V 50 Hz 10 V∙A
1.0 A
CURRENT
OUTPUT
SIGNALING
RS-485
CHANNEL
В
CHANNEL А
CHANNEL
В
CHANNEL А
CURRENT
OUTPUT
SIGNALING
RS-485
~220 V 50 Hz
10 VA 1.0 A

14
 two connectors “CHANNEL А” and “CHANNEL А” for cables connecting
probe units and the converting unit;
 “CURRENT OUTPUT, SIGNALING, RS-485” connector to hook up re-
cording and actuating equipment and to hook up the pH-meter to PC;
 terminal“ « ” to connect protective earthing to the pH-meter frame.
The panel-mounted CU rear panel features the “~220 V 50 Hz 10 V∙A 1.0 A”
mains connector.
The wall-mounted CU lower panel features the “~220 V 50 Hz 10 V∙A 1.0 A”
sealed mains cable entry.
1.5.3.2 Probe unit
1.5.3.2.1 PU-902 probe unit (Fig.1.4 а) and PU-902А probe unit (Fig.1.4 b)
are comprised of:
 amplifier unit;
 temperature sensor;
 electrode system.
а b
2
1
5
4
3
INPUT
1
INPUT
2
INPUT
3
OUTPUT
INPUT
1
INPUT
2
INPUT
3
OUTPUT
6
7

15
Figure 1.4  PU-902 and PU-902А probe units
Amplifier unit 1 has a sealed aluminum housing that features the connectors
as shown in Fig.1.4.
In the PU-902 probe unit the electrode system comprising measuring elec-
trode 2 (рН-electrode) and reference electrode 3 is connected to the “INPUT 1”
and “INPUT 2” connectors.
In the PU-902А probe unit, combination electrode 6 подключается к разъе-
му “INPUT 1”.
Protective collars 4 are intended for water splash protection of electrode
connectors.
Connected to the “INPUT 3” connector is temperature sensor 5, a
thermoresistor enclosed in a metal case.
Connected to the “OUTPUT” connector is a shielded cable hooking up the
probe unit to the converting unit.
There is earthing screw 7 in the amplifier unit lower wall.
1.5.3.2.2 The PU-902LD probe unit is composed of:
 amplifier unit;
 combined electrode;
 temperature sensor.
The PU-902LD probe unit is shown in Fig.1.5а.
а b
6
7
1
2
3
5
4
8

16
Figure1.5
Housing 1 provides sealed protection for the amplifier unit board and contact
joints. The probe unit electrode section (working parts of the combined electrode
and temperature sensor) is protected by housing 2 representing a steel pipe holed
to provide free circulation of analyzed water in the electrode area. Retention screw
8 prevents inadvertent unscrewing of housing 2. Cable 3 sealing is achieved by the
tightening of nut 4. Connector 5 is for the cable hooking up the probe unit to the
converting unit.
As approved by the customer, the probe unit may come complete with pipe 6
and coupling nut 7 for main pipeline measurements, as shown in Fig.1.2b.
1.5.4 Measurement screens
1.5.4.1 Types of measurement screens
The рН-meter has the following measurement screens:
 single channel (А or В) measurement screen as shown in Fig.1.6 and 1.7;
 double channel (А and В) measurement screen as shown in Fig.1.8.
Figure1.6 Figure 1.7
Figure 1.8
Toggling between channel A and B measurement screens and A/B meas-
urement screen is by pressing the “CHANNEL” button.
RANGE
9.0
–
11.0
рН25 9.18
22.0

С
А
RANGE
5.0
–
10.0
рН 6.41
25.7

С
В
RANGE
9.0
–
11.0
рН25 9.18
22.0 С
RANGE 5.0–10.0
рН 6.41
25.7

С
А
В

17
Indicated on the screens are channel names (А or В), upper and lower limits
of programmable measuring subrange values (by current output) and measured
electrode system рН, рН25, U and temperature values.
Toggling among measuring channel indication modes is by successively
pressing the “CHANNEL” button, with channel A or B readings or both channel A
and B readings displayed.
If the probe unit is only connected to one channel, measurements may be
performed for this channel only.
1.5.5 Types of setting monitoring and changing mode screens (MENU
mode)
1.5.5.1 General information on handling the MENU
The pH-meter’s parameters are monitored and changed using the screen
menus.
The MENU mode is entered from the measuring mode by pressing the
“
enter
menu ” button.
The pH-meter has three screen menus:
 MENU [А];
 MENU [В];
 MENU [А] [В].
Toggling among screen menus is by successively pressing the “CHANNEL”
button.
MENU [А] and MENU [В] screens reflect the status of individual channel pa-
rameters and are shown in Fig.1.9.
Figure 1.9
MENU [А] [В] screen reflects the pH-meter’s parameters common for both
measuring channels and is shown in Fig.1.10.
MENU
►CALIBRATION
SETUP
ELECTRODE
MODE: рН
CUR. OUTPUT: 4-20 mА
EXIT
А

18
Figure 1.10
The required menu item is highlighted with the “►” marker moved up and
down the screen with the “”/“” buttons.
After the “►” marker is set at the required menu item, press the “
enter
menu ”
button.
To exit MENU screens, set the marker at EXIT and press the “
enter
menu ” but-
ton.
1.5.5.2 Entry of numerical values in MENU [А], MENU [B] and MENU [А] [В]
As required, the pH-meter allows the user to change numerical values in
menu lines or enter new ones. This concerns, for example, selection of a pro-
grammable current output measuring subrange, entry of threshold values etc.
Left scrolling is by the “CHANNEL” button.
Right scrolling is by the “
enter
menu ” button.
Number increasing or decreasing is by “”/“” buttons.
Proceed as follows to enter or change a numerical value:
 set the “►” marker at this line;
 press the “
enter
menu ” button; the first digit will be flashing;
 use the “”/“” buttons to set the first digit value;
 press the “
enter
menu ” button; the second digit will be flashing;
 use the “”/“” buttons to set the second digit value;
 press the “
enter
menu ” button; set the other digits.
Once all the digits and units of measurements are set (no number is flash-
ing), use the “”/“” buttons to set the “►” marker at another line and enter another
MENU
PASSWORD: OFF
SYSTEM ADDRESS: 00
SOUND: ON
CU TEMPERATURE: 38 С
►EXIT
А В

19
value, if necessary.
Once all the digits and units of measurements are set (no number is flash-
ing), use the “”/“” buttons to set the “►” marker at EXIT and press the “
enter
menu ”
button.
1.5.5.3 Using MENU [А] and MENU [В] screens (Fig. 1.11)
Figure 1.11
► CALIBRATION  a menu item used to select the pH-meter’s pH calibra-
tion mode (see 2.3.8).
► SETUP  a menu item used to view and change a pH measuring
subrange (by current output) and to view and change minimum and maximum pH
threshold values.
The screen is as shown in Fig. 1.12.
Figure 1.12
The user may set values ranging between 0.0 and 14.9 рН (with interval of
0.1 pН) in the RANGE MIN line and those ranging between 0.1 and 15.0 pН (with
interval of 0.1 pН) in the RANGE MAX line.
The difference between pH values in RANGE MAX and RANGE MIN lines is
1 pH, as a minimum.
MENU
CALIBRATION
SETUP
ELECTRODE
MODE: рН
CUR. OUTPUT: 0-5 mА
►EXIT
А
SETUP
RANGE MIN: 1.0
RANGE MAX: 11.0
THRESHOLD M I N: 1.0
THRESHOLD MAX: 11.0
► EXIT
А

20
pH values from 0.0 and 14.9 рН (with interval of 0.1 pН) may be set in the
THRESHOLD MIN line and pH values from 0.1 and 15.0 pН (with interval of
0.1 pН) in the THRESHOLD MAX line.
Once all the required values are set, press the “
enter
menu ” button.
This action will cause the pH-meter confirmation screen as shown in
Fig. 1.13 to be displayed.
Figure 1.13
Use “”/“” buttons to set the “►” marker at YES and press the “
enter
menu ” but-
ton.
The pH-meter will change over to the MENU mode, saving the рН measuring
subrange minimum and maximum values (by current output) and new threshold
values.
► ELECTRODE  a menu item meant to view the electrode system parame-
ters.
Set the “►” marker at this item and press the “
enter
menu ” button.
This action will cause the pH-meter information screen as shown in Fig. 1.14
to be displayed.
Figure 1.14
The display shows the sensor’s parameter values defined by the last calibra-
tion:
S – electrode system transconductance in % of the rated value;
pНi and Еi – coordinates of the electrode system isopotential point.
А
ELECTRODE
S = 97 %
Ei = -24 mВ
рНi = 7.0
►EXIT
А
SAVE ?
YES
► NO