Operating Instruction MA235 1

8/16/2019 Operating Instruction MA235 1

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51709598 a11/96 1

Instruction Manual

This manual contains complete instructions for setting up and using

the MA235 ion analyzer. Applications information is also available.

The information contained in this manual was correct at the time of going to print. However, we continue to improve products and reserve

the right to change specifications, equipment and maintenanceprocedures at any time.

This manual is copyrighted, and all rights are reserved. No part of

this manual may be reproduced by any means or in any form withoutprior consent in writing.

The power supply unit is classed as IEC Class II equipment (equipment

providing an adequate degree of protection against electric shocks, inwhich additional safety precautions, for example, double or reinforced

insulation, are included). The MA235 is intended for use by personsknowledgeable in safe laboratory practices. If the MA235 is not usedin accordance with these instructions for use, the protection provided

by the equipment may be impaired.

The MA235 is suitable for direct current only.

This equipment generates, uses and can radiate radio frequencyenergy and if not installed and used in accordance with the instruc-tion manual, may cause interference with radio communications. Ithas been tested and found to comply with the limits for a Class A computing device pursuant to Subpart J of Part 15 of FCC Rules,

which are designed to provide reasonable protection against suchinterference when operated in a commercial environment. Operationof this equipment in a residential area is likely to cause interferencein which case the user at his own expense will be required to takewhatever measures may be required to correct the interference.

There are no user replaceable parts in the MA235 or power supplyunit. Do not remove the covers.

FS 981/SM 1746


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Contents

1 Set Up

1.1 Unpacking and Installation ................................................ 5 1.2 Input and Output Connections ........................................... 6 1.3 Controls ............................................................................. 7

2 Operation

2.1 pH Measurements ............................................................. 8 2.1.1 Calibrating a pH Electrode ................................................ 8

2.2 mV Measurements .......................................................... 10 2.2.1 Relative mV Measurements ............................................ 10

2.3 Concentration Measurements ......................................... 112.3.1 Calibrating an Ion Selective Electrode ............................ 11

2.4 Known Addition/Subtraction Measurements ................... 13

2.5 Sample Addition/Subtraction Measurements .................. 14

2.6 Temperature Measurements ........................................... 15

2.7 Manual and Auto Endpoint, and Endpoint Time ............. 15 2.8 Sample ID ........................................................................ 16

2.9 Program Menu ................................................................. 17

2.10 Calibration Programming................................................. 19 2.10.1 Calibration Point Setting .................................................. 19 2.10.2 Last Calibration Recall .................................................... 20 2.10.3 mV Offset Setting ............................................................ 212.10.4 Isopotential Point Setting (pH) ........................................ 21

2.11 Display Menu ................................................................... 22 2.11.1 Measurement Channel Selection .................................... 22 2.11.2 Units for Measurement Selection .................................... 22 2.11.3 Display Resolution for pH Selection ................................ 23

2.12 System 1 Menu ................................................................ 26 2.12.1 Time and Date Setting ..................................................... 24 2.12.2 Language Selection ......................................................... 24 2.12.3 Baud Rate Selection ........................................................ 25

2.12.4 Key Press Beeper Setting ............................................... 25

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Contents (cont)

2 Operation (cont)

2.13 System 2 Menu ................................................................ 26 2.13.1 Temperature Mode Selection .......................................... 26 2.13.2 Manual Temperature Setting ........................................... 26

2.13.3 Endpoint Time Setting ..................................................... 27 2.13.4 Meter Self Test ................................................................ 27

2.14 Limits Menu ..................................................................... 29

2.14.1 Alarm Option Selection .................................................... 29 2.14.2 High/Low Limits for pH .................................................... 30

2.14.3 High/Low Limits for Temperature .................................... 30 2.14.4 High/Low Limits for pH Electrode Slope.......................... 31

2.15 Datalog Menu .................................................................. 32 2.15.1 Datalog Selection ............................................................ 32 2.15.2 Interval Timer Setting ...................................................... 32 2.15.3 Recalling Data ................................................................. 33 2.15.4 Clearing Data ................................................................... 34

2.16 GLP Menu........................................................................ 35

2.16.1 GLP Option Selection ...................................................... 35 2.16.2 Cal Alarm Setting............................................................. 35 2.16.3 Entering ID Number ......................................................... 36

2.17 Method Menu ................................................................... 37 2.17.1 Method Saving ................................................................. 37 2.17.2 Method Loading ............................................................... 38 2.17.3 Resetting the MA235 ....................................................... 38

2.18 ISE Menu ......................................................................... 39

2.18.1 Electrode ID Selection ..................................................... 39 2.18.2 Incremental Technique Selection .................................... 39 2.18.3 Known Values for Incremental Techniques..................... 40 2.18.4 Sample Volumes for Incremental Techniques ................ 41

2.19 Chart Recorder ................................................................ 42

2.20 Interfacing via the RS232 Output .................................... 43

2.21 Using an Electrode Selector Box .................................... 46


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Contents (cont)

3 Support Information

3.1 Basic Theory .................................................................... 47

3.2 Operating Hints ................................................................ 48

3.3 Maintenance .................................................................... 50 3.3.1 MA235 Maintenance........................................................ 50 3.3.2 Electrode Maintenance .................................................... 50

3.4 Problem Solving .............................................................. 51

3.5 Specifications .................................................................. 54

Consumables and Accessories ...................................................... 56


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1.1 Installation

1. Unpack the meter, power supply, electrode, electrode arm,

buffer sachets, Guide Book and calibration certificate. Store

the calibration certificate in a safe place.

2. Check the power supply unit is the correct voltage for your

local supply. If it is not, contact your distributor.

3. Attach the electrode arm to the left or righthand side of the

meter:

a. Turn the meter upside down and seat the dome of the

electrode of the electrode arm base into the left or

righthand meter recess.

b. Insert and tighten the fixing screw.

c. Turn the meter and base the right way up and locate the

electrode arm onto the base fixing post. Press down to

snap into place.

1


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1.2 Input and Output Connections

1. Disconnect the shorting clips from the pH sockets and retainby clipping over the socket. If you are using two sensing

electrodes connect them to Channel A and B. If you are using

one electrode, connect it to Channel A.

2. Connect the reference electrode(s), if using, to the Refsocket(s).

3. If you are using an ATC probe connect it to theATC

socket.

If you are using a PT1000 probe connect it to the PT sockets.

4. Connect the power supply unit to the DC socket.

5. When the MA235 is powered up it carries out a display self test.

1power supplyunit socket

reference electrode sockets,Channel A & B

ATC (automatic temperaturecompensation) probe socket

combination or pH electrodesockets, Channel A & B

PT1000 (automatictemperature compensation)probe sockets

data output socket,see Section 2.20for interfacing details

recorder outputsocket, seeSection 2.19for details

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1.3 Controls

Selects pH, mV, relative mV, concentration, knownaddition or sample addition mode.

Accesses software menu from current mode. Exitssoftwaremenu one step at a time.

Selects automatic endpoint, timed endpoint or manualendpoint facility.

Turns the display off, and places the meter in standbymode. Wakes the meter up.

Starts a calibration sequence in pH, concentration andrelative mV modes. Starts sequence in known additionand sample addition modes.

Starts sample measurement in all modes. Press againto manually endpoint. Starts and stops timed datalogging. Returns to measurement from softwaremenu.

Enters sample ID mode.

Selects options in software menu, and enters data orselection.

Used to move around software menu.

Data entry keys, to set calibration buffers, date/time,high/low limits etc. Can also be used to move aroundsoftware menu quickly.

1

7 8 9

4 5 6

1 2 3

0 . -

>> >> > > > > > >

> > > > >> > > > >

Enter

ID

A

Prog

Mode

Read

OnOff

Cal

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2.1 pH Measurements

We recommend regular calibration before sample measurement

(see Section 2.1.1).

To measure the pH of a sample:

Place electrode in sample and press or start the

measurement.

The display shows the pH of the sample. If you are using a

temperature probe the sample temperature is shown, or you can

enter the temperature manually (see Section 2.13.2).

If you are using auto endpoint or timed endpoint the display

freezes automatically (see Section 2.7). To manually endpoint

and freeze the display press

To start a new measurement press

2.1.1 Calibrating a pH Electrode

NOTES If you are using a temperature probe the buffertemperature is shown, or you can enter the temperature

of the buffer manually (see Section 2.13.2).

If you are using auto endpoint or timed endpoint the

display freezes automatically (see Section 2.7). To

manually endpoint and freeze the display press

To calibrate an electrode:

Press If you are using both measurement channels

(A and B), select the one you want to calibrate

using and thenpress>

>

CalpH

Read

Enter

ReadpH

Read

Read

Read

Cal

2


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2.1.1 Calibrating a pH Electrode (cont)

The calibration buffers are shown on the display.

If you want to use other buffers, you will need to enter the values

(see Section 2.10.1).

1 point calibration

Place the electrode in the first buffer. At the measurement

endpoint a tick (4 ) appears on the display.

If you are using a standard buffer the display updates to the

temperature corrected value (see Section 3.5).

The electrode offset is displayed.

To return to sample measurement press

2 point calibration

To continue with a 2 point calibration:

Place the electrode in the second buffer and press

When the display freezes the electrode slope value will bedisplayed.


3, 4 and 5 point calibration

Repeat procedure using the third, fourth and fifth calibration

buffer.

NOTE The buffers can be selected for calibration in any order.

Use and to select the buffer you want to use

for the calibration and press

2

Read

Cal

Read

Cal

> >


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2

2.2 mV Measurements

To measure the absolute mV of a sample:

Place electrode in sample and press to start the measurement.

The display shows the absolute mV of the sample.

If you are using auto endpoint or timed endpoint the display freezes

automatically (see Section 2.7). To manually endpoint and freeze the

display press


2.2.1 Relative mV Measurements

Place electrode in the reference sample and press

The display shows the mV of the reference sample.


freezes automatically (see Section 2.7). To manually endpoint and

freeze the display press

The display updates to 0.0, or an entered value (see Section 2.10.3).

To measure the relative mV of a sample:

Place electrode in sample and press to start the measurement.

The display shows the relative mV of the sample. If you are using

auto endpoint or timed endpoint the display freezes automatically

(see Section 2.7). To manually endpoint and freeze the display

press

If you entered a mV offset (see Section 2.10.3) the sample result

will be the difference between the measured and the set value.


Read

Read

Read

Cal

Read

CalRel mV Mode Read

Read

Read

mV ReadMode

Read


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22.3.1 Calibrating an Ion Selective Electrode NOTES If you are using a temperature probe the temperature of

the standard is shown, or you can enter the temperature

of the standard manually (see Section 2.13.2).

If you are using auto endpoint or timed endpoint the

display freezes automatically (see Section 2.7). To

manually endpoint and freeze the display press

To calibrate an electrode:

Press If you are using both measurement channels

(A and B), select the one you want to calibrate

using and thenpress

2.3 Concentration Measurements

We recommend regular calibration before sample measurement(see Section 2.3.1).

To measure the concentration of a sample:

Place electrode in sample and press to start the

measurement.

The display shows the concentration of the sample (you can

change the units of measurement - see Section 2.11.2). If you areusing a temperature probe the sample temperature is shown or

you can enter the temperature manually (see Section 2.13.2).





concentration

Cal

CalMode

Read

Read

Read

>>

Enter

concentration Mode Read

Read


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2

2.3.1 Calibrating an Ion Selective Electrode (cont)

Five calibration standards are shown on the display. If you want

to use other standards, you will need to enter the values (see

Section 2.10.1).

1 point calibration

Place the electrode in the first standard. At the measurement

endpoint a tick (4 ) appears.

The electrode offset is displayed.


2 point calibration

To continue with a 2 point calibration:

Place the electrode in the second standard and press

When the display freezes the electrode slope value will be

displayed.


3, 4 and 5 point calibration

Repeat the procedure using the third, fourth and fifth calibration

standard.

NOTES The standard set for the first calibration standard is theisopotential point, calibrate in this standard first.

The five standards can be selected for calibration in anyorder.

Use and to select the standard you want

to use for the calibration and

press

Read

Read

Cal

> >

Cal


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2.4 Known Addition/Subtraction Measurements

Enter electrode type and electrode slope, volumes and standardconcentration before measurement (see Section 2.18).

To measure a sample by known addition/subtraction:

Place electrode in sample and press to start the

measurement.

The display shows the first part of the measurement (you can

change the units of measurement - see Section 2.11.2). If you areusing a temperature probe the sample temperature is shown or

you can enter the temperature manually (see Section 2.13.2).




Add the standard to the sample and press

The sample result is shown. If you are using auto endpoint or

timed endpoint the display freezes automatically (see Section 2.7).

To manually endpoint and freeze the display press

NOTE known values (Section 2.18.3) - enter the volume andconcentration of the standard you are using, and the

slope of the electrode.

sample volumes (Section 2.18.4) - enter the volume of your sample as sample volume 1.

Read

Read

Cal

Cal Readk. add Mode

2Read


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2

2.5 Sample Addition/Subtraction Measurements

Enter electrode type and electrode slope, volumes and standardconcentration before measurement (see Section 2.18).

To measure a sample by sample addition/subtraction:

Place electrode in standard and press to start the

measurement.

The display shows the first part of the measurement (you can

change the units of measurement - see Section 2.11.2). If you

are using a temperature probe the temperature of the standardis shown or you can enter the temperature manually (see

Section 2.13.2).




Add the sample to the standard and press

The sample result is shown. If you are using auto endpoint or

timed endpoint the display freezes automatically (see Section 2.7).

To manually endpoint and freeze the display press

You can enter volumes for 4 samples (see Section 2.18.4), so it is

possible to measure 4 samples using the same standard. You can

measure more than 4 samples (the MA235 assumes the samplevolume is that entered for sample volume 4) but for maximum

accuracy we recommend that you only measure 4 samples for

each standard.

To start a new measurement add the next sample to the

standard (and previous sample) and press

The MA235 uses the known values, plus the calculated samplevalue to calculate a new ‘standard value’ and therefore the new

sample measurement.

Cal

Cal Reads. add Mode

Read

Read

Read

Read


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2

2.5 Sample Addition/Subtraction (cont)

NOTE known values (Section 2.18.3) - enter the volume andconcentration of the standard you are using, and the

slope of the electrode.

sample volumes (Section 2.18.4) - enter the volume of your samples (up to 4).

2.6 Temperature Measurements

To measure the temperature of samples and calibration buffers

you must have a temperature probe connected (see Section 1.2).

Select which temperature mode you want to use for each channel

(see Section 2.13.1). If you are using a temperature probe place

the probe in the sample with the electrode when you calibrate

and measure in any mode. The temperature is displayed with the

reading, and the display shows ATC or PT1000.

If you do not have a temperature probe connected or if you

selected manual in temp mode, the display shows MTC. The

temperature displayed will either be the default value of 25°C, ora temperature entered manually, see Section 2.13.2.

2.7 Manual and Auto Endpoint, and Endpoint Time

The auto read control can be used in all modes toselect the endpoint method - manual, automatic or timed.

The automatic endpoint facility checks each measurement to see

if the electrode output is stabilizing, and when the stability

requirements have been met automatically endpoints the

reading. For solutions with long equilibration times (e.g. low

ionic strength samples) it is better to use manual or timed

endpoint.

The endpoint time facility freezes the display after a presetamount of time (see Section 2.13.3). The endpoint time facility is

turned off by setting the endpoint time to 00:00:00.

A


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2.8 Sample ID

The sample number counter increments 1 every time a sample

measurement is endpointed.

To change or reset the sample ID number press

Enter your required sample number using the keypad (enter 0 if

you want to reset the number) and press again.

NOTE If you press while measuring, the sample numberis assigned to that sample.

If you press when the measurement hasendpointed, the number will be

assigned to the next sample.

A

T

M

2.7 Auto Endpoint and Endpoint Time (cont)

Auto endpoint and endpoint time should not be used when using

timed interval data logging.

To use auto or timed endpoint:

press the auto endpoint indicator appears

Press again to select timed endpoint

During calibration or sample measurement the

decimal place flashes until a stable endpoint is

reached, or until the endpoint time has elapsed,

then the display freezes.

To cancel timed endpoint enter 0 as the endpoint time.

NOTES If 0 has been entered as the endpoint time, the manualendpoint indicator appears

The method of endpointing can be saved as part of a

method, see Section 2.17.1.

2 IDID

ID

ID

ID

A


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1 2 3 4 T h e M

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2.9 Program Menu

2


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2.9 Program Menu (cont)

To access the menus:

press the display shows three menu titles at a time (if you

are using both measurement channels (A and B), youhave to select which channel you want to set up).

Press and to move round the menus.You can move

either way, and the menu wraps round

at each end.

Each time you press an arrow key

the next menu title appears, e.g. press

To access your chosen item press or

To choose from options displayed use and then press

Before you can enter or change a value the value must be flashing,

for example: cal 1 = 7.000

Press Change the flashing value using the keypad, then

press again.

Press to return directly to measurement.

< display system 1 system 2 >

channel

conc units Use to move down through the items.

pH resolution2

>>

>

Prog

< calibration display system 1 >

>

< display system 1 system 2 >

Enter

Enter

Enter

Enter

Enter

Enter

Enter

> >

>

Read

To access the menu items, press or when your

required menu is highlighted,

e.g. to access the display menu items press


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2

calibration

cal points

last cal

mV offset

iso

>>

>

Enter

Enter

Enter

Enter

>>

2.10 Calibration Programming

This menu allows you to set 5

calibration points for pH or

concentration; recall data for thelast 10 calibrations, set an offset

value for relative mV mode and set

the isopotential point for pH.

Default refers to the factory

setting which the MA235 uses if no

information is entered.

2.10.1 Calibration point setting

Press or when cal points is highlighted.

If you enter cal points from pH mode, the cal points for pHcalibration are set up. If you enter from concentration mode, the

concentration calibration points are set up, and the standard set

as the first calibration point is the isopotential point.

Use and to select the calibration pointyou want to change and press

The display flashes showing that the value can be changed.

Enter the required value using the keypad and press

# appears if you set a pH calibration value to a standard buffer,

(the value must be the pH value at 25°

C for the standard buffer).The MA235 stores temperature corrected values for the standard

buffers (see Section 3.5).

The next cal point is highlighted. If you want to change this next

point, press and continue as before.

Use and to select another calibration point to change,

OR


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2

2.10.1 Calibration point setting (cont)

press or to leave cal points without any furtherchanges.

Press to return directly to measurement.

NOTE The concentration range of the MA235 is 1.00E –9 to9.99E+9. Enter values in the normal way (for example,

100.0). If you enter a value within the range 0.0001 to

19999 this is how it will be displayed. If you enter avalue outside this range (for example 20500) it will be

converted to exponential format on the display (2.05E+4).

2.10.2 Last calibration recall

Press or when last cal is highlighted.

If you recall the data to the external printer it will print all the

calibration data logged (up to 10 calibrations).

If you recall the data to the display it is shown 4 calibrations at a

time.

Use and to scroll through the data; press to see

further information.

NOTES The MA235 can store data for the last 10 calibrations.

So, if for example 15 calibrations have been carried out,the MA235 stores the data for calibrations 6 to 15.

Calibration data cannot be cleared.

Press to leave last cal.

Press return directly to measurement.

2.10 Calibration Menu (cont)

Prog >

Read

Enter >

>

> > >

Read

Documents

Operating Instruction MA235 1