LTH Electronics HPT63 Operation Manual

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Page 1

HPT63

pH / REDOX TRANSMITTER

OPERATION GUIDE

Page 2

Page 3

Preface

PREFACE

Product warranty

The HPT63 has a warranty against defects in materials and workmanship for three years from the date of shipment. During this period LTH will, at its own discretion, either repair or replace products that prove to be defective. The associated software is provided ‘As is’ without warranty.

Limitation of warranty

The foregoing warranty does not cover damage caused by accidental misuse, abuse, neglect, misapplication or modification.

No warranty of fitness for a particular purpose is offered. The user assumes the entire risk of using the product. Any liability of LTH is limited exclusively to the replacement of defective materials or workmanship.

There are no user serviceable parts, including fuses etc., within the unit. Any attempt to dismantle the instrument will invalidate the warranty.

Disclaimer

LTH Electronics Ltd reserves the right to make changes to this manual or the instrument without notice, as part of our policy of continued developments and improvements.

All care has been taken to ensure accuracy of information contained in this manual. However, we cannot accept responsibility for any errors or damages resulting from errors or inaccuracies of information herein.

HPT63 is a trademark of LTH Electronics Ltd

Second edition: January 2005

Document part number: 6146

LTH Electronics Ltd Chaul End Lane Luton Telephone +44 (0)1582 593693 Bedfordshire Fax +44 (0)1582 598036 LU4 8EZ Email [email protected] United Kingdom Web www.lth.co.uk

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Preface

Manufacturing Standards

Electromagnetic compatibility

This instrument has been designed to comply with the standards and regulations set down by the European EMC Directive

Safety

This instrument has been designed to comply with the standards and regulations set down by the European Low Voltage Directive using BS EN 61010-1 : 1993

Quality

This instrument has been manufactured under the following quality standard:

ISO 9001:2000. Certificate No : FM 13843

Note: The standards referred to in the design and construction of LTH products are

those prevailing at the time of product launch. As the standards are altered from time to time, we reserve the right to include design modifications that are deemed necessary to comply with the new or revised regulations.

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Contents

iii

CONTENTS

1 Introduction ................................................................................................ 1

1.1 About the HPT63 ................................................................................. 1

1.2 Unit Specification ................................................................................. 1

2 Safety & EMC............................................................................................. 3

2.1 Wiring Installation................................................................................. 3

2.2 Noise suppression................................................................................ 3

3 Installation.................................................................................................. 5

3.1 Head-mounted Version Mechanics ...................................................... 5

3.2 Wall-mounted Version Mechanics........................................................ 7

3.3 Dip Tube Assembly.............................................................................. 8

3.4 Connections ......................................................................................... 9

3.5 Digital Inputs ...................................................................................... 12

4 User Interface .......................................................................................... 13

4.1 The Front Panel ................................................................................. 13

4.2 The Menu System.............................................................................. 14

4.3 Unit Configuration .............................................................................. 15

4.4 Number entry ..................................................................................... 16

4.5 Error Messages.................................................................................. 16

5 Main Display............................................................................................. 17

6 Menu Access ........................................................................................... 18

6.1 Changing the Access Code................................................................ 18

7 Parameters .............................................................................................. 19

7.1 Units................................................................................................... 19

7.2 Electrode Type................................................................................... 20

7.3 Temperature Input ............................................................................. 20

7.4 Simulated Input .................................................................................. 21

8 Set Point Relays....................................................................................... 22

8.1 Set Point Source ................................................................................ 23

8.2 Set Point Trigger ................................................................................ 23

8.3 Set Point Mode .................................................................................. 24

8.4 Dose Alarm Timers ............................................................................ 25

8.5 Alarms................................................................................................ 25

8.6 Cleaning............................................................................................. 25

9 Current Output ......................................................................................... 26

9.1 Input................................................................................................... 26

9.2 Select Output ..................................................................................... 26

9.3 Zero & Span....................................................................................... 26

9.4 Proportional Control ........................................................................... 27

9.5 Error Condition................................................................................... 27

10 Calibration................................................................................................ 28

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Contents

10.1 On-Line/Off-Line Operation ................................................................ 28

10.2 Calibration Access.............................................................................. 28

10.3 Calibration Practices........................................................................... 29

10.4 pH Electrode Condition....................................................................... 29

10.5 Redox Sensor Calibration................................................................... 30

10.6 Temperature Calibration..................................................................... 31

10.7 Current Output Calibration.................................................................. 31

10.8 Resetting the User Calibration............................................................ 32

11 Save/Restore ........................................................................................... 33

12 Configuration............................................................................................ 35

12.1 Language ........................................................................................... 36

12.2 Temperature Input Sensor.................................................................. 36

12.3 Error Messages .................................................................................. 36

12.4 Input Filtering (Averaging) .................................................................. 36

12.5 Bargraph............................................................................................. 36

12.6 Software Version ................................................................................ 36

13 Cleaning Menu ......................................................................................... 37

14 Fault Finding ............................................................................................ 39

14.1 Problems With Cables and Connectors.............................................. 41

15 Guarantee and Service ............................................................................ 43

16 Appendix A – Factory Default Setups ...................................................... 45

17 Appendix B – Customer Setup................................................................. 47

18 Appendix C – Redox Solutions................................................................. 49

18.1 Standard Solutions ............................................................................. 49

18.2 Sensor Test ........................................................................................ 49

19 Appendix D – Buffer Solutions ................................................................. 51

20 Appendix E – Temperature Sensor Data ................................................. 52

21 Appendix F – Error Messages.................................................................. 53

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Glossary

iii

GLOSSARY

LCD Liquid crystal display

LED Light Emitting Diode

LSB Least Significant Bit

MSB Most Significant Bit

ppm Parts per million.

ppt Parts per thousand

PRT Platinum Resistance Thermometer.

PSD Programmable System Devices.

Redox Reduction/oxidation. Chemical reaction involving oxidation and

reduction.

RTD Resistive Temperature Device

SP Set point.

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Contents

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1 Introduction

1.1 About the HPT63

The HPT63 is a microprocessor-controlled pH or Redox transmitter. The unit utilises a multifunction LCD to display readings and provide feedback to the operator. It is available with different options to provide fully configurable control, alarm and feedback with up to two relays and two 0/4-20mA current output sources.

1.2 Unit Specification

Measurement input

Single ended or differential with solution ground.

Separate glass and reference electrode pair. Separate Antimony and reference electrode pair or combination electrode

Redox

Separate metal and reference electrode pair or combination electrode. Other manufacturers’ sensors can be accommodated.

Ranges of measurement

0.00 to 14.00pH

-1999mV to +1999mV

-50°C to +300°C

Accuracy

±0.05pH ±3mV

Linearity

±0.1% of range

Repeatability

±0.1% of range

Operator adjustment

pH Antimony Redox

Slope 60-120% 60-120% NA

Offset 3 to 11 pH

-4 to +4 pH

-400 mV to +400 mV

Temperature sensor

PT1000 RTD or 3K Balco thermistor.

Temperature accuracy

±0.2°C

Operator adjustment (Temp)

± 50°C, or ± 122°F

Temperature compensation type

Automatic or manual 0°C to 100°C

Off-Line Facility ( for calibration and commissioning )

The relays are de-energised and the current output is held at the last on-line value. Can be initiated remotely by a contact closure.

Ambient Operating Temperature

-20°C to +50°C (-4°F to +122°F) for full specification.

Ambient temperature variation

±0.01% of range / °C ( typical )

Display

Custom back-lit LCD module. 4 character (& sign) 7 segment (20mm high) for measured value, 2x3 dot matrix for units indication, and 1x16 dot matrix for information and programming.

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1 Introduction

Current output ( optional 1 or 2 outputs )

Each selectable 0-20 mA or 4-20 mA into 1500 Ohms max., fully isolated to 2kV. Expandable up to 5% of any operating range (pH, mV, °C) and offset anywhere in that range.

Operator adjustment ( Current )

±1 mA zero and ±1 mA span for remote monitor calibration

Set points and control relays ( Advanced model only )

Fully configurable set points (pH, mV, °C) with volt free contacts for both relays. Rated at 5A 30V DC / 5A 250VAC (noninductive). Red LEDs indicate relay energised.

Operating modes ( Control, All relays )

On/Off, Time Proportioning, Pulse Proportioning, Band and Clean modes selectable for each relay. Adjustable delay timers up to 10:00 mm:ss and hysteresis in the On/Off mode. Adjustable dose alarm timer up to 15:00 mm:ss in all modes. Adjustable cycle time and proportional band in the proportional modes. Adjustable duration, recovery and interval periods in the clean mode.

Operating modes

The relay can be set to energise on any of the following instrument conditions:Sensor alarm, Dose alarm, Calibration, Off line, Any error

Switches

Four tactile feedback push buttons

EMC : Immunity

BS EN 50082-2 1995

EMC : Emissions

BS EN 50081-1 1992

Safety

Designed and manufactured in accordance with BS EN 61010-1 1993

Power Supply

15 to 30V AC or DC at 200 mA

Head Mount Housing

Conductive ABS blue plastic, rated IP66

Weight

600g (instrument only)

Dimensions

110mm high x 116mm wide x 145mm deep, excluding connectors

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2 Safety & EMC

This chapter describes how to install and mount the panel-mounting and surfacemounting versions, and how to connect the unit to a power source and auxiliary equipment.

Although today’s electronic components are very reliable, it should be anticipated in any system design that a component could fail and it is therefore desirable to make sure a system will fail safe. This could include the provision of an additional monitoring device, depending upon the particular application and any consequences of an instrument or sensor failure.

2.1 Wiring Installation

The specified performance of the HPT63 is entirely dependent on correct installation. For this reason, the installer should thoroughly read the following instructions before attempting to make any electrical connections to the unit.

WARNING! : ALWAYS REMOVE THE MAIN POWER FROM THE SYSTEM

BEFORE ATTEMPTING ANY ALTERATIONS TO THE WIRING. ENSURE THAT BOTH

POWER INPUT LINES ARE ISOLATED. MAKE SURE THAT THE POWER CANNOT BE SWITCHED ON BY ACCIDENT WHILST THE UNIT IS BEING CONNECTED. FOR SAFETY REASONS AN EARTH CONNECTION MUST BE MADE TO THE EARTH TERMINAL OF THIS INSTRUMENT.

ADHERE STRICTLY TO LOCAL WIRING AND SAFETY REGULATIONS WHEN INSTALLING THIS UNIT. SHOULD THESE REGULATIONS CONFLICT WITH THE FOLLOWING INSTRUCTIONS, CONTACT LTH ELECTRONICS OR AN AUTHORISED LOCAL DISTRIBUTOR FOR ADVICE.

To maintain the specified levels of Electro Magnetic Compatibility (EMC, susceptibility to and emission of electrical noise, transients and radio frequency signals) it is essential that the types of cables recommended within these instructions be used. If the installation instructions are followed carefully and precisely, the instrument will achieve and maintain the levels of EMC protection stated in the specification. Any equipment to which this unit is connected must also have the same or similar EMC control to prevent undue interference to the system.

♦ Terminations at the connectors should have any excess wire cut back so that a

minimal amount of wire is left free to radiate electrical pick-up inside or close to the instrument housing.

Note: The use of CE marked equipment to build a system does not necessarily

mean that the completed system will comply with the European requirements for EMC.

2.2 Noise suppression

In common with other electronic circuitry, the HPT63 may be affected by high level, short duration noise spikes arising from electromagnetic interference (EMI) or radio

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2 Safety & EMC

frequency interference (RFI). To minimise the possibility of such problems occurring, the following recommendations should be followed when installing the unit in an environment where such interference could potentially occur.

The following noise generating sources can affect the HPT63 through capacitive or inductive coupling.

♦ Relay coils

♦ Solenoids

♦ AC power wires, particularly at or above 100V AC

♦ Current carrying cables

♦ Thyristor field exciters

♦ Radio frequency transmissions

♦ Contactors

♦ Motor starters

♦ Business and industrial machines

♦ Power tools

♦ High intensity discharge lights

♦ Silicon control rectifiers that are phase angle fired

The HXT63 series is designed with a high degree of noise rejection built in, to minimise the potential for interference from these sources, but it is recommended that you apply the following wiring practices as an added precaution. Cables transmitting low level signals should not be routed near contactors, motors, generators, radio transmitters, or wires carrying large currents.

If noise sources are so severe that the instrument’s operation is impaired, or even halted, the following external modifications should be made, as appropriate:

♦ Fit arc suppressors across active relay or contactor contacts in the vicinity.

♦ Run signal cables inside steel tubing as much as is practical.

♦ Use the internal relays to switch external slave relays or contactors when

switching heavy or reactive loads.

♦ Fit an in-line mains filter close to the power terminals of the supply.

♦ In cases of very high background RF and HF noise environments, LTH can

supply a length of proprietary RF suppressing mains cable.

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3 Installation

3.1 Head-mounted Version Mechanics

This version of the HPT63 is designed for mounting on a pipe T-piece with the sensor in the main current flow.

Figure 1 shows the dimensions of the components required for installation.

Figure 2 shows the dimensions of the completed assemblies.

The two cells are physically similar.

107 mm

112 mm

164.00 mm

pH Sensor 2082/004

Redox Sensor 2529/004

Figure 1 Head-mounting Installation components

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3 Installation

Ø63mm

59Ømm

138mm

116mm

273

70mm

116mm

Figure 2 Head-mounting component dimensions

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3 Installation

3.2 Wall-mounted Version Mechanics

This version is mounted on a wall and connects to sensors via a (maximum) 10m cable. Figure 3 shows the dimensions and fixing points of the unit.

116mm

104mm

140mm

152mm

118mm

73mm

48mm

22mm

Figure 3 Wall-mounted unit dimensions

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3 Installation

3.3 Dip Tube Assembly

BRACKET ASSEMBLY

6081 - PVC-U ANGLED

(NOT SUPPLIED)

FASTENERS

STAINLESS STEEL

PROBE

HOLDER

TANK WALL

1OO

795 or 1395

PROBE

HOLDER

25O to 6OO or 12OO

REQUIRED 36 TO 38 DIA

116

3O DEG

NYLON COATED

TUBE CLIPS

115O MAX

55O MAX

CENTRE HOLE CLEARANCE

FASTENERS

ADJUSTABLE BRACKET

1624 - 316 STAINLESS STEEL

Dims in mm

2O DIA

35 DIA

2O DIA

GASKET/SEAL

(NOT SUPPLIED)

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3 Installation

3.4 Connections

Figure 4 : Panel mount unit, rear view

Connections to the unit are made via the three circular connectors on the side of the unit plus an underside connector for the wall-mounted version. The connections are as follows:

3.4.1 Connector 1 PS Input and Current Outputs

Free female socket

Pin Function

1 Common 0V

2 24V supply

3 Current A output

4 Current B output (Advanced version only)

5 Not used

6 Not used

7 Earth – Connect to power supply earth pin1 to ensure shielding

of electrical circuits.

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3 Installation

3.4.2 Connector 2 Digital Range Selection Inputs

Free female socket. Advanced version only.

Pin Function

1 Digital common

2 Not used

3 Not used

4 Digital input 3

5 Digital input 1

6 Digital input 2

7 Not used

3.4.3 Connector 3 Relay Outputs

Free male plug. Advanced version only.

Pin Function

1 Relay 1 common

2 Relay 1 normally open

3 Relay 1 normally closed

4 Relay 2 common

5 Relay 2 normally open

6 Relay 2 normally closed

7 Not used

3.4.4 Connector 4 Sensor Cable Inputs

Free male plug. Wall-mounted version only.

Pin Function

1 Reference

2 No connection

3 Electrode

4 Temperature input A

5 Temperature input B

6 0V Solution Ground

7 Earth

Note: Pins 4 and 5 each have two wires connected.

See table on next page.

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3 Installation

pH/Redox Connections-to Connector 4

HPT Connector With temperature

element and

solution ground

Without temperature element

Con

Pin Function

Optional

54E extn.

cable

electrode

Optional

LN10 extn.

cable

electrode

Redox

electrode

1 Reference * Inner

screen

Black Screen or

black wire

Screen or black wire

Screen or

black wire 2 N/C 3 Electrode Green core Clear core Clear core Clear core Clear core 4 Temperature

compensation

Yellow wire & blue wire

Red

5 Temperature

compensation

Black wire &

white wire

Black

6 0V Solution

Ground

Clear core Green

7 Earth Outer screen

*Note: On the extension cable, use the inner screen around the green core as the

Reference connection. The inner screen around the clear core is not used – cut it back.

3.4.5 Power Supply

The unit requires a supply between 15 and 30V (24V nominal) at 200 mA.

Note: The maximum current output load resistance depends on the unit supply

voltage: R

load

(Ohms) = (V

supply

-2) / 0.04

3.4.6 Current Output Connections

The Basic HPT63 has a single current output of 0-20 or 4-20 mA. The Advanced version has two such outputs designated A and B. The current output ranges are selected via the instrument menu.

For best noise immunity use a screened twisted pair cable, with the screen connected to Earth at one end.

Use a sufficiently large cable to avoid a high resistance in the overall current loop.

3.4.7 Relay Connections

The relay outputs are available only on the Advanced version. The relay contacts are volt-free (electrically isolated) and can handle up to 5A at 30V DC or 250V AC. They must be connected in series with a 5 Amp fuse.

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3 Installation

Figure 5 : Relay contact connection

Depending on the load, a contact arc suppressor may be required to prevent excessive electrical noise. To switch more than 5 Amps, use a slave relay.

Figure 6 : Slave relay connection

3.5 Digital Inputs

The digital inputs are used to externally initial a cleaning cycle or to take the unit off line. These inputs are intended to be switched using a volt-free link, switch or relay. Closing a contact initiates the action.

The connections to connector 2 are as follows:

Ground to pin 6 = clean

Ground to pin 4 = off line.

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4 User Interface

WARNING! Before proceeding, ensure that the installation instructions have

been followed correctly. Failure to do so may result in an electrically hazardous installation, or degrade instrument performance.

When shipped, the HPT63 is configured to the default pH set-up ( see Appendix A – Factory Default Setups). In this state the instrument can perform all of the necessary

function for a basic pH monitoring instrument.

4.1 The Front Panel

The HPT63 uses a versatile LCD to display all of the settings and readings. The seven segment digits at the top of the display indicate the primary measured value during normal operation. The six character display to the right of these indicates the units of measurement when a value is being displayed. The sixteen characters on the bottom of the display to indicate secondary readings or states, and display scrolling error messages.

Along with the LCD display, the front panel also incorporates five LEDs. The two outer LEDs (labelled 1 and 2) indicate the set point status, i.e. when the LED is illuminated the indicated relay is active. The centre LED indicates when the unit is Off-line. Note: Not all relay channels may be fitted.

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4 User Interface

The four keys -

, , and - allow the user to control and configure the unit. The keys are used for changing display options, navigating around the menu system and for changing unit parameter values. To operate a key, press it until the display responds (about half a second). If you hold a key down, the display will cycle through the available options at a rate of about one per second.

4.2 The Menu System

The fold-out sheet at the end of the manual shows the menu system. Each column

constitutes a menu. Use the

(Page) key to move from one menu column to the

head of the next. When you select the next menu, the display shows the menu title

e.g. Parameters. Pressing

with moves backwards through the menus.

Use the and keys to move up and down the menu options in each column. Depending on the current settings, some menu options may not be present. For example, if Set Point 1 is disabled, the screen displaying Set Point 1 will not appear.

When the instrument is switched on, it shows the main display screen. You can use

the

and keys to select various display options, depending on the

configuration of the unit. However, on pressing the

(page) key to reach the configuration menus, the first screen encountered is the Access Code screen. To proceed beyond this screen you must enter an access code as detailed in Section 18

Menu Access.

Note: When in the menu structure, if none of the buttons are pressed for two

minutes, the unit will time out and return to the main display. The Access Code display will be reset to 0000, 30 seconds after returning to the main display.

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4 User Interface

4.3 Unit Configuration

The unit can be configured by navigating around the menu system and setting up the various unit facilities.

The general principle of setting a parameter is as follows:

1. Use the

, , and keys to navigate to the parameter to be changed.

2. Press the key to select the parameter for editing. The current parameter

value will start to flash, indicating that it can be changed.

3. Use the

and keys to cycle through the available values of the parameter

to the required value.

4. Press the

key to confirm your selection of the required value. The

parameter value will stop flashing, indicating that it has been set.

5. Use the

, , and keys to navigate to the next parameter to be changed.

This method can be used for:

• Turning a facility on or off, e.g. Temperature Compensation in the

Parameters menu. The

and keys toggle the facility on and off.

• Selecting between several options, e.g. Unit types in the Parameters menu.

• Setting a numeric value such as an access code or trigger level. See Section

4.4 Number entry.

For functions such as Resets and Restoring Setups, press the

key to initiate the

function, the system will then ask for confirmation. Press

to confirm the function:

or to cancel.

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4 User Interface

4.4 Number entry

The , and keys allow you to set up a number between 0000 and 9999 on the main seven-segment display as a parameter value or access code.

To set up a number, proceed as follows:

1. Press

to begin editing a number. The first (left-hand) digit will start to flash.

2. Use the and keys to increment or decrement the flashing digit.

3. When the flashing digit is correct, press to confirm the setting. The next

digit will start to flash.

4. Repeat steps 2 and 3 to set the remaining three digits.

5. After pressing

to confirm the last digit, none of the digits will be flashing and

the number is then ready for use.

If the number is an access code, the Padlock symbol on the display will change to a Key symbol if the new code you have entered is correct. If the number is a parameter value, the parameter has now been set to that value.

4.5 Error Messages

If the internal diagnostics have detected an error condition, the appropriate error message will flash on the bottom row of the display. A reference to these error

messages can be found in Appendix F – Error Messages. Pressing the

key

when an error message is flashing will scroll a more detailed description of the error

along the bottom line. Pressing

again will return the unit to the flashing display.

The error messages can be disabled within the Configuration menu (see Section

12.2 Error Messages). If the error messages are disabled, the display will flash a bell symbol on the far right of the bottom row when an error is detected. It is possible to configure a set point relay to provide external signalling of error conditions (see Section 8.5 Alarms).

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5 Main Display

There are two modes of display operation – digital and bargraph. The mode can only be changed via the Configuration menu, requiring a Level 2 access code.

In bargraph mode, the display shows an analogue representation of Output A or B, or both, alternating. The output identity and units are shown in the upper display.

In digital mode, the display shows the sensor reading, in the units assigned via Parameters/Units, on the top row and a secondary reading on the bottom row. The user can select the desired secondary reading parameter by means of the

and keys. If bargraph display has been enabled, digital readings can be selected but the bargraph display will be restored after a timeout period. The secondary parameters vary according to the instrument configuration, and are as follows:

Sec. display Comment

Temp. input Units C or F, as selected via

Parameters/Temperature Units

Output A This shows the output current from Channel A in mA.

Output B This shows the output current from Channel B in mA.

SP1 This appears when Set Point 1 is enabled and trigger is set to Low or High.

It shows set point value in the assigned units.

SP1H This appears when Set Point 1 is enabled and trigger is set to Band, Latch Lo

or Latch Hi. It shows set point upper value in the assigned units.

SP1L This appears when Set Point 1 is enabled and trigger is set to Band, Latch Lo

or Latch Hi. It shows set point lower value in the assigned units.

SP2 This appears when Set Point 2 is enabled and trigger is set to Low or High.

It shows set point value in the assigned units.

SP2H This appears when Set Point 2 is enabled and trigger is set to Band, Latch Lo

or Latch Hi. It shows set point upper value in the assigned units.

SP2L This appears when Set Point 2 is enabled and trigger is set to Band, Latch Lo

or Latch Hi. It shows set point lower value in the assigned units.

The default secondary parameter can be set by selecting the parameter and pressing

the

key (provided that no error messages are present). This is the parameter that is displayed on the bottom line when the unit is switched on, or as a result of a timeout back to the normal display mode.

If the unit has detected an error, an error message will flash alternately with the secondary parameter or bargraph. See Appendix F – Error Messages.

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6 Menu Access

The instrument parameters are protected against unauthorised or accidental tampering by access codes.

There are three levels of access – Basic, Level 1 and Level 2. For Basic access, no access code is required but access is restricted to the main display modes. A user with Level 1 access can change some parameters and Set Point trigger levels. A user with Level 2 access has full access to all user-selectable parameters. The pullout chart at the rear of this manual shows the access permitted the three levels.

When the unit is switched on, it shows the main display screen. To reach the menu

system from there, press the

key to reach the Access Code screen and then enter the Level 1 or Level 2 access code. A character on the right of the display indicates whether or not access is permitted. The character will be a key for permitted access and a padlock for denied access.

As supplied, the unit has the following default access codes:

0001 Restricted access at Level 1. 0002 Full access at Level 2.

On first use, it is recommended that the user change the access codes to restrict unauthorised access. See Section 6.1 Changing the Access Code.

Entering the access code for a level, e.g. for Level 2, gives access to that level. The procedure for entering the access code is detailed in Section 4.4 Number entry. On entering a valid code, the padlock character on the display changes to a key.

6.1 Changing the Access Code

On first use, it is recommended that the user change the access codes to restrict unauthorised access.

You need Level 2 access in order to change the Level 2 access code. You can change the Level 1 access code if you have either Level 1 or Level 2 access.

1. From the Main Display screen, press

once to reach the Access Code

screen.

2. Use the

and keys to reach the Set Level 1 (or 2) Code screen.

3. Use the , and keys to edit and store the new access code, as

described in Section 4.4 Number entry.

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7 Parameters

The Parameters menu contains the basic configurations for the sensor inputs. The various parameters can be changed using the method described in Section 4.3 Unit Configuration.

The Parameters menu structure is as follows:

| | 0-100 °C

Simulated input

7.1 Units

The HPT63 can be set up as either a pH or a Redox instrument. This is achieved by simply setting the appropriate units (either pH or mV). The rest of the menu structure for the instrument responds by enabling and disabling the appropriate menu items (e.g. the slope calibration menu is disabled when mV are selected). When “mV” are selected the instrument displays the unprocessed input voltage to the electrode terminals, this can also be used as a diagnostic tool for pH measurements. All appropriate set point levels etc. have their units changed automatically.

When pH is selected the HPT63 will automatically apply the correct temperature compensation and electrode type to the mV input to provide a display of pH. All of the set point units etc. will then be changed to pH. The temperature compensation is referenced to either the measured input temperature or a fixed user selectable temperature (which one, depends on the temperature compensation mode, see Section 7.3 Temperature Input).

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7 Parameters

7.2 Electrode Type

The HPT63 can scale its pH input readings to operate with either a glass or antimony electrode. This sets the isopotential point, for a glass electrode this is 7.00pH, for an antimony electrode it is 0.00pH.

7.3 Temperature Input

The HPT63 has a very accurate temperature measurement facility. The user can apply either automatic or manual temperature compensation to the pH measurement. The operator can select between these two modes of operation by selecting the Temp Comp menu item within the Parameters menu. Note the temperature input must be enabled under the Configuration menu (see Section 12.2). It is also possible to select the temperature sensor type in this menu. When the manual mode of operation is selected, the user can enter the fixed process temperature under the Fixed Temp menu.

Note: When the automatic mode is selected the Fixed Temp menu will not be

present.

Note: When the unit detects a fault in the temperature sensor it will default to using

the Fixed Temp setting for compensation purposes.

The operator can also select to display all temperatures in either °C or °F by selecting the Temp Units menu. All temperature related displays will reflect the units selected in this menu.

Note: The system will under normal conditions convert all temperature related

variables when the units are changed, however it may be wise for the operator to ensure that changing the units has not altered the set points or current outputs.

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7 Parameters

7.4 Simulated Input

The facility exists within the HPT63 to simulate the input sensor levels to test the set point and current output operation. This function allows the user to cycle up and

down through the sensor range using the

and keys keys and display the

current output level, with the relays responding accordingly.

To select the Simulate menu item from the Parameters menu, press the

key.

The unit will now display the simulation menu. Pressing the

and keys will cycle the displayed value between its minimum and maximum levels in steps of 1% . In Redox mode, the steps are 1% of -2000mV to +2000mV i.e. 40mV. In pH mode, the steps are in 0.20pH. The relays and current output will respond as if the displayed value were an actual input, thus allowing the user to debug the set point and current output configurations.

Page 30

8 Set Point Relays

Two Set Point relays, designated SP1 and SP2, are fitted on the Advanced version of the HPT63. No relays are fitted on the basic version. Indicators on the front panel show when a relay has operated.

A relay can be set to operate when a sensor or temperature set point is exceeded or when an alarm occurs. The menu structures for set points 1 and 2 are identical, and provide a high level of flexibility in the configuration of the relay outputs, as follows:

Cleaning – see Section 13 | Duration | Interval | On/Off-line | Recovery time (Off-line) or Delay Y/N (On-line)

Page 31

8 Set Point Relays

8.1 Set Point Source

Each set point relay can be disabled or triggered from a sensor input (the default), a temperature input or from an alarm.

8.2 Set Point Trigger

The set points can be configured to trigger from the sensor or temperature source in six ways:

Trig: Hi The relay will be activated when the source input becomes greater

than the set point. Delay and hysteresis can be applied.

Trig: Lo The relay will be activated when the source input becomes less than

the set point. Delay and hysteresis can be applied.

Trig: Band The relay will become activated when it is either greater than the

Band High set point, or lower than the Band Low set point. Delay and hysteresis can be applied.

Trig: Latch Lo the relay energises when the source input falls below the Band Low

level and remain energised until it rises above the Band High level. It then remains de-energised until the sensor input falls below the Band Low level again.

Trig: Latch Hi the relay energises when the source input rises above the Band

High level and remain energised until it falls below the Band Low level. It then remains de-energised until the sensor input rises above the Band High level again.

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8 Set Point Relays

8.3 Set Point Mode

The relays can operate in one of three modes.

8.3.1 On/Off Mode

The On/Off mode is the default mode of operation for the relays. The relay energises when the set point is activated and is de-energised when the set point is deactivated.

Delay

: In order to prevent short duration changes at the input affecting the relay operation a delay can be set before the relay energises. If the input is still the same after the delay, then the relay will be energised.

Hysteresis

: A facility to apply hysteresis to the set point level allows the user to avoid relay chatter when the sensor input level approaches the set point level. Chatter is caused when the sensor input is sufficiently close to the set point value and noise on the signal repeatedly crosses the set point level, thus causing the relay to switch on and off rapidly.

The hysteresis level should therefore be set to be a little larger than the input noise level.

In addition to the On/Off mode the HPT63 also provides two forms of pseudo proportional control, which can be used to control the levels to a defined value when used in conjunction with a pump or valve. When the reading deviates from the programmed set point level the relay pulses at a rate proportional to that deviation.

8.3.2 Time Proportional Mode

It is possible to control any on/off device such as a solenoid valve or dosing pump using the time proportional mode.

The proportional band is displayed as a percentage of the full range value. For example, a proportional band of 20% on the 0-14 pH range would give a band of 2.8 Ph. If the set point trigger was selected as LOW and the set point value was 7 Ph, the band would cover 4.2 to 7.0 pH. When the reading falls below 4.2 pH the relay would be energised. As the input rises and approaches the set point the output relay starts to cycle on and off with the on time reducing and the off time increasing, respectively. The cycle time can be set by the user and is the sum of the on and off times.

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8 Set Point Relays

8.3.3 Pulse Proportional Mode

The Pulse Proportional (or PP) mode is intended to drive solenoid type dosing pumps which have the facility to accept an external pulse input. The proportional band operates in the same way as the Time Proportional mode. The output relay now operates by producing a series of pulses of fixed duration. The pulse rate increases as the measurement moves further from the set point, until it reaches the maximum frequency at the limit of the proportional band (i.e. 4.2 pH in the previous example).

8.4 Dose Alarm Timers

The dose alarm timer can be used to prevent overdosing under many different fault conditions , such as sensor failure or wiring faults. When the timer is enabled the user can set the Alarm Time. If the associated relay remains energised for longer than the Alarm Time the alarm will activate, de-energising the relay to prevent over- dosing and flash the set point LED on the front panel. The display will also flash a warning message when the alarm is activated.

Note: During pulse or time proportional operation, the cumulative on-time that the

set point is active will be taken.

To cancel the warning, and reactivate the set point, press the

key on the front

panel.

Note: If more than one Alarm is active, set point 1 takes priority over set point 2 and

they are cancelled in that order by additional presses of the key.

8.5 Alarms

The two set point relays can be configured as an alarm output triggered by one of the following events:

• Sensor error

• Dose alarm

• Calibration – when a calibration is in progress.

• Off-line – unit has been taken off line, e.g. for servicing.

• Any error – when any system error is detected.

To set an alarm output, choose the SP1 or SP2 menu, select Alarm from the menu options and then select the required trigger.

8.6 Cleaning

The Cleaning menu options allow a set point relay to be used for controlling a device for cleaning the sensor. For information on sensor cleaning, refer to Section 13.

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9 Current Output

The current output menu structure contains all of the necessary set-up functions to configure the current output source(s). If one current output is fitted, then the menu will be as follows. If two current outputs are fitted they are referred to as A and B respectively.

The menu structure is as follows:

O/P Source (A or B) Sensor IP | Select Output (0/4-20 mA)

On Error = (No, 22 mA or 0 mA)

The maximum load resistance that the current output can drive depends on the power supplied to the unit and is: R

load

(Ohms) = (Vpower –2) / 0.04.

9.1 Input

The unit can use the sensor input or the temperature input as the sources for the current outputs. Alternatively, the source can be switched off by selecting Disabled for that source.

9.2 Select Output

The output range for the current output can be set to one of two ranges, either 0 – 20 mA or 4-20 mA. This selection sets the limits of the zero and span output levels. The output will continue to provide an extrapolated output above (>20 mA) and below ( <4 mA ) these points but will flag an error message on the main display. The maximum current limit is approximately 22 mA, the minimum limit is 0 mA (i.e. the unit cannot source a negative current)

9.3 Zero & Span

The zero and span levels define the limits of the source input. This provides a totally flexible method of configuring the current output. The zero can be set anywhere within the input source range and the span up to 5% of the range, providing total control of the output range and offset. An inverse relationship can easily be achieved by simply setting the zero level to be higher than the span level.

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9 Current Output

9.4 Proportional Control

Many devices such as motor speed controllers, valve actuators, or stroke positioners will accept an analogue 4-20 mA control signal.

It is possible to use the measurement signal from the instrument as a control signal. By setting the point at which the output is 4 mA as the set point (e.g. 7 pH) and the point at which the output is 20 mA as the proportional band (e.g. 4 pH) a simple form of proportional control is achieved. If this signal were used to drive a valve actuator, the valve would be fully open at 4 pH, half open at 5.5 pH and closed at 7 pH.

9.5 Error Condition

The current outputs can be programmed to output 22 mA or 0 mA when an error is detected on the source ( i.e. Sensor Fault, Temperature Over or Under Range ). This can provide remote warning of error conditions or to ensure fail safe operation. The default state is disabled (parameter set to No).

Page 36

10 Calibration

The HPT63 provides the facility within the Calibration menu to adjust the sensor inputs and current output levels to tailor the unit to the system in which it is operating.

The menu structure is as follows:

Calibration

10.1 On-Line/Off-Line Operation

Selecting the Mode menu will allow the user to place the unit in the Off-line state. If the state is set to Off-line the relays will be de-energised and the current output level frozen for the duration of the Off-Line state. When On-Line is selected the relays and current output will operate normally. The middle LED on the front panel display will indicate when the unit is Off-Line.

10.2 Calibration Access

A feature has been included in the HPT63 to allow users to access the sensor calibration from the main display. To enable this feature, set Cal Access? to Y. To disable this feature, thus preventing the users from altering the calibration from the main display, set Cal Access to N.

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10 Calibration

10.3 Calibration Practices

Observe normal good practices when calibrating electrode systems against standard solutions.

• Always clean the electrode system before inserting in the standard solution to avoid contamination and to obtain the best response from the electrode system.

• Rinse the electrode system in clean (preferably demineralised) water between standard solutions.

• Allow time for the electrode system temperature to stabilise in each standard solution.

• Use standard solutions of known quality. If in doubt make up fresh solutions.

• Use clean beakers and bottles for standard solutions.

• The HPT63 can be taken offline, which de-energises the relays and holds the

current outputs at their last values. This facility is useful when calibrating the system, however the operator must ensure the relays are in a safe state when using this feature.

10.4 pH Electrode Condition

Depending on the measurement environment, sensor sensitivity (slope) can vary with age and, hence, periodic slope recalibration may be required. The buffer (offset) value can also be adjusted, but this should not require regular adjustment once the unit has been set up for a given sensor.

For a glass electrode, the buffer (offset) adjustment after calibration will be displayed as 7 pH ±2 pH. For antimony electrode, the adjustment will be displayed as 0 pH ±2 pH. The Slope Limit adjustment for a glass electrode is 80% to 110%, for an antimony electrode 75% to 115%.

10.4.1 pH Buffers

LTH supplies buffer powders which are prepared from pure dry chemicals, sealed in a sachet or capsule which prevents the absorption of moisture and subsequent deterioration. Prepare buffer solutions in accordance with the instructions supplied with the buffer powders.

Using the Buffer and Slope menu items, it is possible to do single (Buffer only) or two-point calibration,. It is important to do the calibration in the correct order:

1. Buffer (Offset) adjustment at 7 ±2 pH

2. Slope (Gain) adjustment at another pH – normally 4 or 9 pH (for two point calibration only)

The output from an ideal glass/reference electrode pair will normally be 0mV at 7pH.

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10 Calibration

Check the temperature of the solutions. From the documentation supplied with the solutions, determine the true values of the solutions at the measured temperatures. Use these (true) values for calibration purposes.

Note: Appendix D – Buffer Solutions lists typical buffer solution pH values at various

temperatures.

Prepare a beaker of clean, preferably de-mineralised water for washing the sensor between measurements.

10.4.2 Procedure

For each prepared buffer solution, carry out the following procedure:

1. Wash sensor in de-mineralised water.

2. Insert the sensor in the prepared buffer solution.

3. From the Sensor Buffer or Sensor Slope page, press the key. The screen will display ‘Are you sure?’.

4. Press to confirm (or any other key to abandon calibration). On pressing , the display will show the sensor reading.

5. Use the and keys to set the reading to the known true (temperaturecompensated) value of the solution.

6. Press

to confirm the correct reading. The display will show the buffer or slope calculated by the instrument (where 0 pH and 100% are the default values).

7. Rinse the sensor in clean water.

10.5 Redox Sensor Calibration

For the Redox setup only the offset (zero) can be adjusted - by ±200mV. To adjust the Redox offset, with the sensor units in mV, select the Sensor Buffer menu item from the Calibration menu.

10.5.1 Redox Standards

Unlike pH electrodes, the Redox electrode’s slope does not change. Nevertheless, incorrect Redox potentials may occasionally be measured and the cause of these errors is usually a contaminated platinum (Pt) surface, or a contaminated or plugged reference junction.

Standard Redox solutions are available from various sources at potentials of 385 mV (from LTH), 124, 200, 250, 300, 465, 600 and 650 mV. It is possible to make up standards as detailed in Appendix C – Redox Solutions.

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10 Calibration

10.5.2 Procedure

1. Make up a standard Redox solution in accordance with the instructions supplied.

2. Immerse the electrode system in the solution.

3. From the Sensor Buffer page, press the

key. The screen will display ‘Are

you sure?’.

4. Press to confirm (or any other key to abandon calibration). On pressing , the display will show the sensor reading..

5. Use the and keys to set the reading to the potential of the solution, e.g. 358 mV.

6. Press

to confirm the correct reading. The display will show the offset

calculated by the instrument (where 0mV is the default).

10.6 Temperature Calibration

Use this option to calibrate the temperature sensor against a solution at a known temperature. Proceed as follows:

1. Ensure that the sensor is immersed in a solution of known temperature.

2. From the Temperature Calibration page, press the

key. The screen will

display ‘Are you sure?’.

3. Press to confirm (or any other key to abandon calibration). On pressing , the display will show the temperature reading.

4. Use the and keys to set the reading to the known correct temperature.

5. Press to confirm the correct reading. The display will show the slope calculated by the instrument (where 100% is the default).

10.7 Current Output Calibration

The user is provided with an opportunity to adjust the current output, to calibrate any equipment that may be being used to monitor the current output signal. To adjust the current output select the Current Output menu item in the Calibration menu. Please keep in mind that the current output cannot go below 0mA. The maximum offset is ±2mA. If two current outputs are fitted they are referred to as A and B respectively.

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10 Calibration

10.8 Resetting the User Calibration

This option resets all of the user calibrations to their default. From the Reset User

Cal page, press the key. The message ‘Are you sure?’ will appear. Press to

confirm and continue with the reset, or any other key to abandon the reset.

Page 41

11 Save/Restore

This facility allows you to save and recover two instrument set-ups. The menu structure is as follows:

Save/Restore Save as Setup A Save as Setup B Restore Setup A Restore Setup B Default pH Default Redox

To use these functions select the Save/Restore menu item and use the

and

keys to select the required function. Pressing the key will prompt the unit to ask

for confirmation. Pressing the

key again will initiate the function. The unit will

then perform the function and then return to the main menu.

This facility is very useful for testing or fault finding. The set-up can be stored prior to testing and restored once testing is complete. The default set-ups are provided to give a basic instrument set-up for each configuration.

Note: There is no protection for the set-up stores other than the systems request for

confirmation, so be very careful not to overwrite already saved set-ups.

There are three banks of data that can be interchanged as required.

• Working Data: the operating data and set-up parameters that are used by the

instrument and which can be changed or viewed on the display by the user.

• Primary backup: the A stores can be written to or read back as a block of data.

Data in these stores cannot be viewed without first loading it into the Working data stores. This read back will overwrite the existing Working data, leaving the A store data unchanged.

•

Secondary backup: the B stores can be written to or read back as a block of data. Data in these stores cannot be viewed without first loading it into the Working data stores. This read back will overwrite the existing Working data, leaving the B store data unchanged.

When an individual parameter is saved, the corresponding data is copied into a single non-volatile memory location. (This simply means the data is not lost when the power is removed or interrupted.)

When a complete programme sequence or set-up has been entered into the working data stores, the whole set-up can be copied (using Save/Restore) into either the A or B stores. We strongly recommend that this feature is used.

It is also possible to restore the default parameters. This can be useful for fault finding, since a working configuration can quickly and easily be programmed in to aid

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11 Save/Restore

commissioning or testing the instrument. Remember to Save the normal set-up first and restore it afterwards.

If corruption of data is reported by the software with an error message, the saved setup can be copied back into the Working stores from either the A or B stores.

Page 43

12 Configuration

Options on the Configuration menu allow you to set up some basic operating parameters. The menu structure is as follows:

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12 Configuration

12.1 Language

This option is not available on some (English-only) units.

Use the and keys to select the required language and the key to confirm your selection.

12.2 Temperature Input Sensor

Use the and keys to select or disable the temperature sensor and the key to confirm your selection.

12.3 Error Messages

Use this option to display or hide any error messages that may occurs. Error messages flash alternately with the secondary parameters on the display.

12.4 Input Filtering (Averaging)

When very noisy environments are encountered, this function will allow the user to filter the sensor readings by taking a running average over the time period selected (from 10 seconds to 5 minutes).

12.5 Bargraph

The display can include a bargraph that shows the state of the current outputs. Use the Bargraph configuration option to turn the bargraph off or to display output current A or B, or both, alternating.

Digital display can only be restored by changing the Bargraph option under the Configuration menu.

12.6 Software Version

This option displays the version number of the software embedded in the unit.

Page 45

13 Cleaning Menu

Cleaning Duration Interval On/Off-line Recovery time (Off-line) or Delay Y/N (On-line)

A set point relay can be configured to operate a jet spray wash or rotary electrode cleaning system on a timed cycle. The purpose is to prevent accumulation of particulate matter on the active surfaces of the sensor. The Set Point relay would control the supply to the cleaning device.

The Cleaning item on the Set Point menu (see Section 8 Set Point Relays) has the following parameters:

Duration – The duration of the cleaning operation (5s to 10 min.)

Interval – The interval between cleaning operations (5 min to 48 hours).

On/Off line – The required system state during a cleaning operation. When Off line,

the other current output and relays are disabled.

Recovery – This option only appears if Off-line has been selected. This is the time

allowed for the sensor to recover from cleaning. It is the time from the end of cleaning to the return to the On-line state (5s to 10 min).

Delay Y/N – This option only appears if On-line has been selected. If unit is to

remain On line during cleaning, a Y option forces the cleaning to wait until all relays are inactive. While cleaning is being delayed, an E23 error message may be displayed.

The instrument can be taken off-line during a ‘Clean’ cycle. This will de-energise the set point relay and freeze the current output which could otherwise cause chaos in the control system as a result of cleaning solution being sprayed onto the sensor.

By selecting the automatic Off-Line facility in the menu, spurious relay / current output changes are prevented during the Duration and Recover periods. Normal operation is restored during the Interval period. The clean Delay function gives priority to the control relays. This means that a ‘Clean’ cycle will be delayed for as long as necessary until the control relays are in the Off state.

A manual clean cycle can be initiated by a remote switch/contacts connected to the instrument digital input terminals (see Section 3.4 Connections). The ‘Clean’ cycle software, if selected, runs automatically and continuously from power up, beginning with the Interval period. It can only be stopped by changing the operating mode of the Set Point relay or Current output which it is controlling.

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13 Cleaning Menu

Typical Operation with Clean Offline

Duration

Clean Relay

Set point

Relay

Current

Output

Offline

Lamp

Recovery Interval

off

Hold

Normal

Page 47

14 Fault Finding

NOTE : THERE ARE NO USER SERVICEABLE PARTS INSIDE THE UNIT

The HPT63 has been designed to include a wide range of self diagnostic tests, some of which are performed at switch on, and some on a continuous basis. This guide aims to provide a route to diagnosing and correcting any faults that may occur during normal operation. The table shown in Appendix F – Error Messages gives a list of the error messages that the HPT63 generates, along with their probable causes. If the fault has not been cleared after these checks have been made, contact LTH. Please have as much of the following information available as possible, in any communication with LTH, to enable quick diagnosis and correction of the problem.

• Serial number of the instrument,

• The approximate date of purchase.

• Details of the program settings and application

• Electrical environment and supply details

• Circumstances under which the fault occurred.

• The nature of the fault or faults

• Any error messages that are displayed

• The sensor type, cable length and type

• Current output configuration

• Relay connection configuration

• Software version.

It is often worthwhile to check the measurement by an independent method, for example using a handheld meter. (See also Section 2.2 Noise suppression.)

The Instrument Appears Dead

Check that power is available to the unit. Using a voltmeter, set to AC or DC (as appropriate), check the power supply voltage at the connector. The unit can accept from 15 to 30V AC or DC. Check that the power cable is securely and correctly attached – wired as detailed in Section 3.4 Connections. There are no user serviceable fuses fitted within this unit.

The Access Code Does Not Work

It is probable that the access code has either been changed or the operator does not recall the code correctly. Contact LTH or your local distributor should this problem arise.

The Sensor Reading Is Constantly Over-range or Under-range

1. Ensure that the sensor and temperature inputs are correctly connected (wall-

mounted version only, see Section 3.4 Connections) and that the sensor is not faulty or damaged.

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14 Fault Finding

2. Check that the correct sensor units have been selected within the

Parameters menu (see Section 7.1 Units).

3. If the units are set to pH, check the temperature compensation state (see

Parameters Section 7.3 Temperature Input). If the compensation is set to Manual, check that the fixed temperature is at the correct level. If the compensation is Automatic, check that the temperature reading on the main display is correct.

4. Check the sensor using a hand held meter.

The Sensor Reading Is Incorrect

♦

If reading pH, check that the correct electrode type has been selected (see Section 7.2 Electrode Type).

♦

Check that no error messages are being displayed (see Appendix F – Error Messages). Check that the sensor cable has been correctly connected (wall-mounted version only - see Section 3.4 Connections).

♦

Check that the Temperature reading is correct.

♦

Check the instrument calibration using a pH simulator. Adjust the user calibration if necessary (see Section 10 Calibration).

♦

Use another instrument to check the sensor.

The Sensor is not Functioning Correctly

♦

Check that the sensor glass is not broken or cracked.

♦

Check the reference electrode KCl (where applicable) for leakage or contamination.

♦

Ensure all electrode protective caps have been removed

♦

Check that any junction boxes used are correctly connected.

♦

Check that a suitable high impedance, low noise cable has been used.

♦

Check for damaged or broken cables.

♦

Check for damp, grease, or liquids near connectors, junction boxes, or terminations.

♦

Where extension cables have been used, try connecting the sensor directly to the instrument.

The Temperature Reading Is Incorrect

♦ Check that the temperature sensor is correctly attached. (wall-mounted

version - see Section 3.4 Connections).

♦ Check that the temperature sensor type is correctly selected in the

Configuration menu (See Section 12.2 Temperature Input Sensor)

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14 Fault Finding

♦

Where practical check the temperature sensor resistance against the table in Appendix E – Temperature Sensor Data.

Current Output is Incorrect or Noisy

♦ Check that the maximum load resistance for the current loop has not been

exceeded. (1000Ω). Maximum load resistance is related to the supply voltage by the equation R

max

= (V

supply

-2)/0.04.

♦ Check that the terminals have been wired correctly (see Section 3.4

Connections).

♦ Check that the cable screen is attached to Earth at one end, and that the

cable does not pass too close to a power cable (see Section 2.2 Noise suppression).

♦ Check that the current output has been configured properly (see Section

10.7 Current Output Calibration).

Relays Appear to Malfunction

♦ Check that the unit is On-Line (see Section 10.1 On-Line/Off-Line Operation)

♦ Check that the set point configuration is correct (see Section 8 Set Point

Relays)

♦ If the relays are vibrating or ‘chattering’ as they pass the set point, check the

hysteresis setting (see Section 8.3.1 On/Off Mode) and increase if necessary.

♦

Ensure that the relays are connected properly (see Section 3.4.7 Relay Connections) and that the voltage/current levels are not exceeding the specification (see Section 1.2 Unit Specification).

♦

Check that the instrument input cables are not picking up excessive noise, (see Section 2.2 Noise suppression).

A Bell Symbol is Flashing on the Display

The system has detected an error but the error messages have been disabled in the Configuration menu (See Section 12.3 Error Messages). Enable the error messages, correct the error and then disable the error messages only if absolutely necessary.

14.1 Problems with Cables and Connectors

The cable connecting the pH electrode to the instrument is the most common cause of problems in pH measurement systems. The importance of the following recommendations cannot be over stressed.

Input Resistance

The high input resistance, required for the optimum performance from a pH electrode system, will be seriously degraded if any grease, dirt, or dampness is allowed to

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14 Fault Finding

collect around any of the connections between the electrode and the instrument. This includes any connectors or junction boxes which may be used. Particular attention must be paid to the method of extending the pH electrode cable. A general rule would be the fewer connections there are, the less problems are likely to occur.

Input Cable

The choice of cable is important. Only polythene or PTFE cables are acceptable. Secondly, any vibration or cable movement on a standard co-axial cable will give rise to fluctuations in the readings. To prevent this a low noise cable must be employed. This type of cable can be identified as having a black impregnated polythene layer which is exposed when the outer braid is separated for connection. This must be completely removed at the terminations to avoid a possible short circuit between the electrode and reference pair.

In all cases the screening braid must not be separated from the core conductor by more than 5mm in order to avoid “hum” pickup.

Cables should be kept as short as possible and must be run separately (100mm separation typically) from any power carrying cable.

Cable Length

The response of the instrument to a sudden change in the sensor input will be determined mainly by the source resistance of the electrode and the length of the connection cable. For a typical pH electrode of 1000MΩ resistance, in combination with a typical cable, the time taken to settle to its new value is about 0.5 seconds per metre of cable ( depending on the cable capacitance ).

Problems with Electrodes

The combination electrodes supplied by LTH are of low resistance and will be less affected by humidity than other, high resistance systems. In any case, the connecting leads and cable connectors must be kept dry, and the cable screen must not be allowed to come into contact with any earthed metal parts. The glass bulb must be kept in a moist condition for correct operation. If the electrode is allowed to dry out, it may be recovered by immersing in a saturated KCl solution or dilute acid for at least 24 hours before use.

Electrodes can be expected to last for at least one year under normal operating conditions before replacement becomes necessary. However operation at elevated temperatures or pressures, and the presence of sulphides or ionic metals, will shorten the electrode life. If the electrode cannot be set up against solutions or shows a sluggish response to changes in pH, it should be replaced.

Page 51

15 Guarantee and Service

Products manufactured by LTH Electronics Ltd are guaranteed against faulty workmanship and materials for a period of three years from the date of despatch, except for finished goods not of LTH manufacture, which are subject to a separate agreement.

All sensors made by LTH Electronics Ltd are thoroughly tested to their published specification before despatch. As LTH have no control over the conditions in which their sensors are used, no further guarantee is given, although any complaints concerning their operation will be carefully investigated.

Goods for attention under guarantee (unless otherwise agreed) must be returned to the factory carriage paid and, if accepted for free repair, will be returned to the customer’s address free of charge. Arrangements can also be made for repair on site, in which case a charge may be made for the engineer’s time and expenses.

If any services other than those covered by the guarantee are required, please contact LTH direct.

Note: Overseas users should contact their LTH nominated representative. Special

arrangements will be made in individual cases for goods returned from overseas.

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15 Guarantee and Service

Page 53

16 Appendix A – Factory Default Setups

Parameters pH Redox

Units pH mV

Electrode Type Glass N/A

Temperature Units

°C °C

Temperature Compensation Automatic N/A

Fixed Temperature Input

+25.0°C +25.0°C

Set Points

SP1 Source Sensor Sensor

SP1 Trigger Low Low

SP1 Level ( Band High ) 7.00pH 200mV

SP1 Band Low 4.00pH 100mV

SP1 Mode On/Off On/Off

SP1 Dose Alarm No No

SP1 Alarm Time (mm:ss) 05:00 05:00

SP1 Delay ( mm:ss ) 00:00 00:00

SP1 Hysteresis ( % of SP Level ) 1.0% 1.0%

SP1 Cycle Time ( mm:ss ) 00:30 00:30

SP1 Proportional Band ( % of range )

20.0% 20.0%

SP2 Source Sensor Sensor

SP2 Trigger High High

SP2 Level ( Band High ) 9.00pH 300mV

SP2 Band Low 4.00pH 100.0mV

SP2 Mode On/Off On/Off

SP2 Dose Alarm No No

SP2 Alarm Time (mm:ss) 05:00 05:00

SP2 Delay ( mm:ss ) 00:00 00:00

SP2 Hysteresis ( % of SP Level ) 1.0% 1.0%

SP2 Cycle Time ( mm:ss ) 00:30 00:30

SP2 Proportional Band (% of range)

20.0% 20.0%

Page 54

16 Appendix A – Factory Default Setups

Cleaning

Duration ( mm:ss ) 00:05 00:05

Interval ( hh:ss ) 01:00 01:00

Mode Off-Line Off-Line

Recovery ( mm:ss ) 00:05 00:05

Delay N N

Current Output

Output A Source Sensor Sensor

Output A Mode 4-20mA 4-20mA

Output A Zero 0.00 pH 0 mV

Output A Span 14.00 pH + 1000mV

Output B Source Temperature Temperature

Output B Mode 4-20mA 4-20mA

Output B Zero 0.00 0.00

Output B Span 100°C 100°C

On error No No

Calibration

Mode On-Line On-Line

Calibration Access No No

Configuration

Language English English

T Input Pt1000 Pt1000

Errors Enabled Enabled

Input Filter Out Out

Page 55

17 Appendix B – Customer Setup

Use this appendix to record unit settings.

Instrument Serial No ……………………………

Sensor Serial/Type No ……………………………

Parameters

Set up

Units

Electrode Type

Temperature Units

Temperature Compensation

Fixed Temperature Input

Set Points

SP1 Source

SP1 Trigger

SP1 Level ( Band High )

SP1 Band Low

SP1 Mode

SP1 Dose Alarm

SP1 Alarm Time (mm:ss)

SP1 Delay ( mm:ss )

SP1 Hysteresis ( % of SP Level )

SP1 Cycle Time ( mm:ss )

SP1 Proportional Band (% of range)

SP2 Source

SP2 Trigger

SP2 Level ( Band High )

SP2 Band Low

SP2 Mode

SP2 Dose Alarm

SP2 Alarm Time (mm:ss)

SP2 Delay ( mm:ss )

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17 Appendix B – Customer Setup

SP2 Hysteresis ( % of SP Level )

SP2 Cycle Time ( mm:ss )

SP2 Proportional Band (% of range)

Cleaning

Duration ( mm:ss )

Interval ( hh:ss )

Mode

Recovery ( mm:ss )

Delay

Current Output

Output A Source

Output A Mode

Output A Zero

Output A Span

Output B Source

Output B Mode

Output B Zero

Output B Span

On error

Calibration

Mode

Calibration Access

Configuration

Language

T Input

Errors

Input Filter

Bargraph

Page 57

18 Appendix C – Redox Solutions

18.1 Standard Solutions

For calibration and test purposes, standard solutions at various potentials can be purchased.

LTH Electronics offers 2 standard solutions: Part No. 138/175 124mv Redox solution, 500ml.

Part No. 138/176 358mv Redox solution, 500ml.

18.2 Sensor Test

Calibration of the HPT63 in the Redox mode is a single point calibration only.

Page 58

18 Appendix C – Redox Solutions

Page 59

19 Appendix D – Buffer Solutions

The following table gives the LTH buffer solution values. Prepare and use buffer solutions in accordance with the instructions supplied with them.

pH variation against temperature

Temperature (°C)

4 pH Buffer 7 pH Buffer 9 pH Buffer

0 4.00 7.11 9.49

10 4.00 7.06 9.35

20 4.00 7.01 9.24

25 4.01 7.00 9.19

30 4.02 6.98 9.14

40 4.04 6.97 9.07

50 4.06 6.97 9.01

60 4.09 6.97 8.96

70 4.13 6.99 8.92

80 4.16 7.03 8.89

90 4.21 7.08 8.87

Page 60

20 Appendix E – Temperature Sensor Data

The table below lists approximate resistance values of temperature sensors that may be used with the HXT63 series. Not all options are available on all models.

Temperature

( °C )

PT1000

RTD

Balco

1000.0Ω 2670Ω

1039.0Ω 2800Ω

1077.9Ω 2930Ω

1097.3Ω 3010Ω

1116.7Ω 3070Ω

1155.4Ω 3200Ω

1194.0Ω 3340Ω

1232.4Ω 3470Ω

1270.7Ω 3610Ω

1308.9Ω 3740Ω

1347.0Ω 3880Ω

100

1385.0Ω 4020Ω

Page 61

21 Appendix F – Error Messages

Switch On Diagnostic Errors

E01 Processor RAM Read/Write Error

Try switching the unit off then on again. If the message persists, consult with your supplier, as this unit will require to be returned for repair.

E02

Reserved for future use

E03 PSD RAM Read/Write Error

Try switching the unit off then on again. If the message persists, consult with your supplier, as this unit will require to be returned for repair.

E04 Setup Checksum Error

The instrument configuration has for some reason become corrupted. Restore a setup from store A or B, or one of the two default setups.

E05 Store A Checksum Error

The data in setup store A has been corrupted. Save the current setup back to store A.

E06 Store B Checksum Error

The data in setup store B has been corrupted. Save the current setup back to store B.

E07 Factory Calibration Checksum Error

The factory calibration data for this instrument has been corrupted.

The instrument will need to be re-calibrated. Consult your supplier.

E08 User Calibration Checksum Error

The user calibration data has been corrupted. Reset the user calibration and re-enter

Calibration/Sensor Errors

E11 1V Cal Err

Factory +1.0V calibration value is out of specification. Sensor requires recalibration. Contact LTH or agent.

E12 -1V Cal Err

Factory -1.0V calibration value is out of specification. Sensor requires recalibration. Contact LTH or agent.

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21 Appendix F – Error Messages

E13 Min Temp Cal

Factory temperature zero calibration value at zero.

Temperature sensors require recalibration. Contact LTH or agent.

E14 Max Temp Cal

Factory temperature span calibration value at maximum.

Temperature sensors require recalibration. Contact LTH or agent.

E15

> ±200 mV

mV sensor buffer exceeds ±200 mV limit. Try fresh buffer solution. Check sensor for damage and replace if necessary.

E16

> ±2 pH

pH sensor buffer exceeds ±2 pH limit. Try fresh buffer solution. Check sensor for damage and replace if necessary.

E17 User Sensor Slope

User sensor slope calibration below spec. Try fresh buffer solution. Check sensor for damage and replace if necessary.

E18 User Sensor Slope

User sensor slope calibration above spec. Try fresh buffer solution. Check sensor for damage and replace if necessary.

Set Point/Cleaning Errors

E21 SP1 Dose Alarm SP1 has exceeded the maximum allowed dosing

period. Check setup.

E22 SP2 Dose Alarm SP2 has exceeded the maximum allowed dosing

period. Check setup.

E23 Cleaning delayed Control set point active. Cannot clean until it is de-

energised.

Sensor Input Errors

E31 Sensor +Sat

The sensor input at positive saturation.

E32 Sensor -Sat

The sensor input at negative saturation.

E33 Sensor Input Over-range

The sensor input over the specified range

E34 Sensor Input Under-range

The sensor input is under the specified range

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21 Appendix F – Error Messages

E35 Temperature Sensor Fault

The temperature sensor is reading open or closed circuit, due in most cases to a damaged sensing element or incorrect wiring. Check Configuration menu Temperature Sensor is set to the correct type. Under this condition, the unit will default to the fixed temperature setting for compensation purposes.

E36 Temperature Input Over-range

Temperature input is greater than +300.0°C Could be a result of the faults listed under Error E35.

E37 Temperature Input Under-range

Temperature input in less than -50.0°C Temperature. Could be a result of the faults listed under Error E35.

E38 Compensation Outside Limits

The temperature reading is less than 0.0°C or greater than 100.0°C, leading to an error in compensation.

Current Output Errors

E41 Current Output A Hardware Fault

The current output circuit has detected an error in the output. This is most commonly due to either a broken loop or too large a load resistor. It can also be caused by insufficient supply voltage for the load (see Section 3.4.5 Power Supply).

E42 Current Output B Hardware Fault

E43 Sensor Input < Current OP A Zero Level

The sensor input level is below that set for current output A zero.

E44 Sensor Input > Current OP A Span Level

The sensor input level is above that set for current output A span.

E45 Sensor Input < Current OP B Zero Level

The sensor input level is below that set for current output B zero.

E46 Sensor Input > Current OP B Span Level

The sensor input level is above that set for current output B span.

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21 Appendix F – Error Messages

Floating Point Maths Errors

These errors are only flagged when an internal maths calculation fails. As such, they should not appear if the software is functioning properly. The error message should time out after approx. 5 seconds. If the error continues to be displayed, call LTH or an authorised distributor for advice.

E51 Overflow Error

E52 Underflow Error

E53 Divide by 0 Error

E54 Too Large For Conversion

E55 Too Small For Conversion

Page 65

Index

Access

Code .......................................................22

Entry....................................................... 22

Levels ..................................................... 22

Alarm.......................................................... 29

Averaging................................................... 40

Bargraph............................................... 21, 40

Bell Symbol................................................ 20

Buffer .........................................................33

Cal access ................................................... 33

Calibration.................................................. 32

Current output......................................... 36

Offset...................................................... 34

Resetting................................................. 36

Temperature ...........................................35

Calibration alarm........................................ 29

Cleaning .....................................................41

Relay control ..........................................29

Configuration ....................................... 19, 20

Connections................................................ 13

Current output......................................... 15

Relays..................................................... 16

Current output ............................................ 30

Calibration.............................................. 36

Connections............................................ 15

Input source ............................................ 30

Max. resistive load .................................15

Output range........................................... 30

Zero & Span ...........................................30

Delay .......................................................... 41

Display........................................................17

Dose alarm..................................................29

Electrode type .............................................24

EMC............................................................. ii

EMI...............................................................8

Error............................................................31

Error message .....................20, 21, 40, 43, 57

Fault Finding...............................................43

Filtering ......................................................40

Guarantee....................................................48

Input filtering..............................................40

Installation ....................................................9

Interference...................................................8

Isopotential point ........................................24

Key Symbol ................................................22

Keys......................................................18, 22

Language ....................................................40

LCD ............................................................17

LEDs...........................................................17

LVD............................................................. ii

Main Display Menu ....................................21

Menu system...............................................18

Noise filtering .............................................40

Noise suppression .........................................8

Off-line ...........................................17, 29, 32

Alarm ......................................................29

Offset ....................................................33, 34

On-line........................................................32

Output current.............................................21

Padlock Symbol ..........................................22

Parameters...................................................23

Index

Page 66

Index

Proportional band ................................. 28, 29

Proportional control.................................... 31

Quality.......................................................... ii

Ranges .......................................................... 5

Recovery .................................................... 41

Redox Offset ..............................................34

Relay ..........................................................26

Relay connections ...................................... 16

Relays

Specification............................................. 6

Remote warning .........................................31

Returns .......................................................48

RFI................................................................ 8

Safety ...........................................................ii

Secondary parameter .................................. 21

Self diagnostic tests.................................... 43

Sensor

Accuracy .................................................. 5

Sensor error ................................................29

Set point ............................................... 21, 26

Delay ......................................................28

Dose alarm.............................................. 29

Hysteresis ............................................... 28

On/Off Mode .......................................... 28

PP Mode ................................................. 29

Relay.......................................................26

Source .....................................................27

TP Mode .................................................28

Trigger ....................................................27

Slope ...........................................................33

Software version .........................................42

Standards ..................................................... ii

Supply Voltage

Specification .............................................6

System error................................................29

Temperature

Accuracy...................................................5

Ambient Variation ....................................5

Calibration ..............................................35

Compensation .........................................24

Fixed .......................................................24

Operating ..................................................5

Sensor .....................................................40

Units........................................................24

Tests............................................................43

Timeout.......................................................18

Units

Temperature............................................24

Warranty ................................................. i, 48

Wiring.....................................................7, 13

Page 67

Sensor &

temperature

ACCESS CODE PARAMETERS SET POINTS 1 & 2

CURRENT

OUTPUT

CALIBRATION

SAVE /

RESTORE

CONFIGURATION

× Ø

Sensor &

current O/P A

Edit Level 1 access code

Display units SP1 source O/P A source Online / offline

Save as Setup A

2 Language

× Ø

Sensor &

current O/P B

Edit Level 2 access code

Electrode type SP1 trigger

O/P A mode ( 0/4-20 mA )

Cal Access

Save as Setup B

Temperature

sensor

× Ø

Sensor &

set point 1 *

Temperature units

SP1 level

( band high )

O/P A zero

pH buffer/

Redox offset

Restore Setup A

Error messages

× Ø

Sensor &

set point 2

TC mode SP1 band low O/P A span

pH Slope

(N/A to Redox)

Restore Setup B

Input filter

× Ø

Bargraph

Manual

temperature

SP1 mode O/P B source Temperature

Restore default

Bargraph on/off

× Ø

Simulated current

output A

SP1 dose alarm

O/P B mode (0/4-20 mA )

Current O/P A

Restore default

Redox

Software issue

× Ø

Simulated current

output B

SP1 delay O/P B zero Current O/P B

× Ø

SP1 hysteresis O/P B span

Reset User Calibration

× Ø

SP1 cycle time Source error

× Ø × Ø

SP1 proportion

band

Key:

× Ø

Universal access SP2 source

× Ø

Level 1 access

Etc, as SP1

Level 2 access

Notes :

1. The Current Output menu will only appear when the unit is configured for Current Outputs.

2. The Language option is not available on some (Englilsh-only) units.

3 Depending on unit settings, some menu items may not appear. (See the appropriate sections in the main text.)

4. N/A = not applicable

HPT63

Page 68

LTH Electronics Ltd

Chaul End Lane

Luton

Bedfordshire

LU4 8EZ

United Kingdom

Telephone : +44 (0) 1582 593693

Fax : +44 (0) 1582 598036

e-mail : [email protected]

web : www.lth.co.uk