Hamilton EPHUM011 Programmer's Manual

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pH ARC Sensors Modbus RTU Programmer’s Manual (EPHUM011)

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pH ARC Sensors

Modbus RTU

Programmer’s Manual

Firmware version:

EPHUM011

pH ARC Sensors Modbus RTU Programmer’s Manual (EPHUM011)

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Important Notice

The contents of this manual are subject to change without notice. Technical changesreserved. All efforts have been made to ensure the accuracy of the contents of this manual. However, should any

errors be detected, HAMILTON Bonaduz AG would greatly appreciate being informed of them. The above notwithstanding, HAMILTON Bonaduz AG can assume no responsibility for any errors in

Rev. Revision Date Author Change Description 01 22.04.2010 Ph. Arquint

R. Dietrich D. Schönfuss

Initial Version 01 for EPHUM011

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Table of Content

1 MODBUS RTU GENERAL INFORMATION ............................................................................... 4

1.1 INTRODUCTION ..................................................................................................................... 4

2 PH ARC SENSOR COMMANDS IN MODBUS RTU................................................................... 5

2.1 GENERAL.............................................................................................................................5

2.2 OPERATOR LEVELS AND PASSWORDS ..................................................................................... 5

2.2.1 Reading / Setting Operator Level................................................................................. 5

2.2.2 Changing Passwords for Operator Level .....................................................................6

2.3 CONFIGURATION OF THE SERIAL RS485 INTERFACE ................................................................. 7

2.3.1 Device Address........................................................................................................... 7

2.3.2 Baud Rate................................................................................................................... 8

2.4 CONFIGURATION OF THE ANALOG INTERFACES......................................................................... 9

2.4.1 Available Analog Interfaces......................................................................................... 9

2.4.2 Available Analog Interface Modes ...............................................................................9

2.4.3 Description of the Analog Interfaces 1 and 2.............................................................. 10

2.4.4 Selection of an Analog Interface Mode...................................................................... 10

2.4.5 Configuration of the 4-20 mA Interface...................................................................... 11

2.4.6 Reading the InternallyMeasured Output Current....................................................... 17

2.5 MEASUREMENT................................................................................................................... 18

2.5.1 Definition of Measurement Channels and Physical Units ........................................... 18

2.5.2 Primary Measurement Channel 1 (pH) ...................................................................... 20

2.5.3 Primary Measurement Channel 6 (Temperature)....................................................... 22

2.5.4 Definition of the Measurement Status for PMC1 / PMC6............................................ 23

2.5.5 Secondary Measurement Channels 1-16................................................................... 24

2.6 CONFIGURATION OF THE MEASUREMENT ............................................................................... 26

2.6.1 Available Parameters................................................................................................ 26

2.6.2 PA9: Moving Average................................................................................................ 27

2.6.3 PA12: Moving Average R.......................................................................................... 30

2.7 CALIBRATION...................................................................................................................... 32

2.7.1 Available Calibration Points....................................................................................... 32

2.7.2 Definitions of Calibration Points................................................................................. 33

2.7.3 Calibration Procedure................................................................................................ 35

2.7.4 Reading the Calibration Status.................................................................................. 44

2.7.5 Currently active Calibration Parameters part 1........................................................... 48

2.7.6 Currently active Calibration Parameters part 2........................................................... 48

2.7.7 Currently active Calibration Parameters part 3........................................................... 49

2.7.8 Currently active Calibration Parameters part 4........................................................... 49

2.7.9 Special Commandsfor Calibration with VISICAL....................................................... 50

2.7.10 Calibration Standards................................................................................................ 51

2.8 SENSOR STATUS ................................................................................................................ 57

2.8.1 Temperature Ranges ................................................................................................ 57

2.8.2 Operating Hours and Counters.................................................................................. 58

2.8.3 Warnings .................................................................................................................. 59

2.8.4 Errors........................................................................................................................ 60

2.8.5 Reading Definition of SIP and CIP............................................................................. 62

2.8.6 Reading the Sensor’s Quality Indicator...................................................................... 63

2.9 SENSOR IDENTIFICATION AND INFORMATION........................................................................... 64

2.9.1 General Information .................................................................................................. 64

2.9.2 Sensor Identification.................................................................................................. 64

2.9.3 Free User Memory Space ......................................................................................... 65

2.10 SYSTEM COMMANDS ........................................................................................................... 66

2.10.1 Recall Sensor’s Factory Settings............................................................................... 66

3 ABBREVIATIONS.................................................................................................................... 66

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1 Modbus RTU general information

1.1 Introduction

This document describes in detail the pH ARC Sensors Modbus RTU interface. It is addressed to software programmers.

The general information about Modbus command structures and its implementation in the HAMILTON ARC Sensor family is described in detail in Chapter 1 of the

“VISIFERM DO Modbus RTU Programmer’s Manual”(p/n 624179/01). If you need this general information about Modbus programming, then please consult p/n 624179/01. In the present manual, only the specific command structure for the pH ARC Sensors is described. It is

valid for the firmware version:

EPHUM011 Please check the software version by reading register 1032. This present definition of the command structure is an additional document to the Operating

Instructions of the specific pH ARC Sensors. Before reading this manual, the operating instructions of the sensors should be read and understood.

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2 pH ARC Sensor Commands in Modbus RTU

2.1 General

In order to communicate with a pH ARC Sensor over Modbus RTU protocol a Modbus master terminal application software is needed. The Modbus RTU is an open standard and a number of free and commercial application toolkits are available.

This manual contains examples and illustrations from WinTECH Modbus Master ActiveX Control tool: WinTECH (www.win-tech.com) “Modbus Master OCX for Visual Basic”. The Modbus Organisation (www.modbus.org/tech.php) provides other links to a wide variety of Modbus terminal softwares.

In the present manual the addressing of the Modbus registers starts at 1. But the Modbusmaster protocol operates with register addresses starting at 0. Usually, the Modbus master software translates the addressing. Thus, the register address of 2090 will be translated by the Modbus master software to 2089 which is sent to the sensor (Modbus slave).

Attention: When configuring and calibrating the sensor, please limit write operations to a reasonable number. More than 100’000 write operations will physically damage the memory of the sensor. Furthermore, for the Free User Memory Space (see chapter 2.9.3), the write operations are limited to 10’000.

2.2 Operator levels and Passwords

2.2.1 Reading / Setting Operator Level

A pH ARC Sensor can be operated in three different operator levels. Each operator level allows a defined access to a specific set of commands.

Abbreviation Description Code (hex) Password (decimal) U User (lowest level) 0x03 0 A Administrator 0x0C 18111978 S Specialist 0x30 16021966

Figure 2.2.1.1: Definition of operator level and default passwords At each power up or processor reset, the operator level falls back to the default level U. The active operator level can be read and written in register 4288.

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Modbus

function code

Read access

Write access

4288 4 Operator Level Password 3, 4, 16 U/A/S U/A/S

Figure 2.2.1.2: Definition of register 4288.

Command: Active operator level

Modbus address: 4288 Length: 4 Type: 3

Read Parameter: Operator level Password Format: hex decimal Value:

0x03 0

Figure 2.2.1.3: Example to read the active operator level (function code 3, start register address 4288,

number of registers 4): The active operator level is 0x03 (User). The sensor does not report the password. The value 0 is returned instead.

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Command: Operator level

Modbus address: 4288 Length: 4 Type: 3

Read Parameter: Operator level Password Format: Hex decimal Value:

0x30 0

Figure 2.2.1.4: Example to read the active operator level: the active level is 0x30 (Specialist). The

sensor does not report the password. The value 0 is returned instead.

Command: Operator level

Modbus address: 4288 Length: 4 Type: 16

Write Parameter: Operator level Password Format: Hex decimal Value:

0x03 0

Figure 2.2.1.5: Example to set the operator level to 0x03 (User). The password 0 has to be sent.

Command: Operator level

Modbus address: 4288 Length: 4 Type: 16

Write Parameter: Operator level Password Format: Hex decimal Value:

0x0C 18111978

Figure 2.2.1.6: Example to set the active operator level to 0xC (Administrator). The correct password

has to be sent.

Command: Operator level

Modbus address: 4288 Length: 4 Type: 16

Write Parameter: Operator level Password Format: Hex decimal Value:

0x0B 18111978

Figure 2.2.1.7: Example for a Modbus error. If the level or the password is not correct, (Operator level =

0x0B), the sensor answers with a Modbus error message “Slave device exception response” (see chapter 1.6).

2.2.2 Changing Passwords for Operator Level

The passwordsfor accessing the operator levels A and S can be modified by S (Specialist) only. U (User) and A (Administrator) have no right to change any password. The new password will remain stored after power down.

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Modbus

function code

Read access

Write access

4292 4 Level New password 16 None S

Figure 2.2.2.1: Definition of register 4292.

Command: Password

Modbus address: 4292 Length: 4 Type: 16

Write Parameter: Operator level Pass number Format: Hex Decimal Value:

0x30 12345678

Figure 2.2.2.2: Example to set the Password of operator level S (code 0x30) to 12345678.

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2.3 Configuration of the serial RS485 Interface

Factory settings of the RS485: Parity is none, 1 start bit, 8 data bits, 2 stop bits (in total: 11 bits).

2.3.1 Device Address

2.3.1.1 Reading and Writing the Device Address

The sensor specific device address can be read and written in register 4096.

Start

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write access

4096 2 device address 3, 4, 16 U/A/S S

Figure 2.3.1.1.1: Definition of register 4096.

Command: Com address

Modbus address: 4096 Length: 2 Type: 3

Read Parameter: Modbus address Format: Decimal Value:

Figure 2.3.1.1.2: Example to read the device address. The device address can be set by S (Specialist), default value is 1.

Command: Com address

Modbus address: 4096 Length: 2 Type: 16

Write Parameter: Modbus address Format: Decimal Value:

Figure 2.3.1.1.3: Example to set the device address to 3.

2.3.1.2 Reading the Device Address Limits

The device address limits can be read in register 4098.

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Modbus

function code

Read access

Write access

4098 4 Min. device

address

Max. device address

3, 4 U/A/S none

Figure 2.3.1.2.1: Definition of register 4098.

Command: Com address limits

Modbus address: 4098 Length: 4 Type: 3

Read Parameter: Min value Max value Format: Decimal Decimal Value:

1 32

Figure 2.3.1.2.2: Example to read the device address limits: Min = 1, Max = 32.

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2.3.2 Baud Rate

2.3.2.1 Reading and Writing the Baud Rate

The baud rate can be read and written in register 4102.

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write access

4102 2 Baud rate code

(definition see below)

3, 4, 16 U/A/S S Figure 2.3.2.1.1: Definition of register 4102. The code for the baud rate is defined as follows:

Baud rate 4800 9600 19200 38400 57600 115200 Code 2 3 4 5 6 7

Figure 2.3.2.1.2: Code for the baud rates.

Command: Com baud rate

Modbus address: 4102 Length: 2 Type: 3

Read Parameter: Baud rate code Format: Decimal Value:

Figure 2.3.2.1.3: Example to read the baud rate code, 4 corresponds 19200 baud. The baud rate can be set by S (Specialist), default is 19200.

Command: Com baud rate

Modbus address: 4102 Length: 2 Type: 16

Write Parameter: Baud rate code Format: Decimal Value:

Figure 2.3.2.1.4: Example to set the baud rate to 38400 baud with code 5.

2.3.2.2 Reading the Baud Rate Limits

The baud rate limits can be read in register 4104.

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Modbus

function code

Read access

Write access

4104 4 Min. Baud rate

code

Max. Baud rate code

3, 4 U/A/S none

Figure 2.3.2.2.1: Definition of register 4104.

Command: Com baud limits

Modbus address: 4104 Length: 4 Type: 3

Read Parameter: Min Baud rate code Max Baud rate code Format: Decimal Decimal Value:

2 7

Figure 2.3.2.2.2: Example to read the baud rate code limits: Min = 2, Max = 7 (see Figure 2.3.2.1.2).

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2.4 Configuration of the Analog Interfaces

2.4.1 Available Analog Interfaces

A pH ARC Sensor has two individual physical analog interfaces that have identical functionalities, but can be configured independently from each other.

 Analog Output Interface 1 (AO1)  Analog Output Interface 2 (AO2)

The number of analog interfaces is defined in register 4320.

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write access

4320 2 Available analog interfaces 3, 4 U/A/S none

Figure 2.4.1.1: Definition of register 4320.

Command: Avail analog interfaces

Modbus address: 4320 Length: 2 Type: 3

Read

Parameter: Available analog

interfaces Format: Hex Value:

0x03

Figure 2.4.1.2: Example to read the available analog interfaces. The answer is “0x03”meaning that

there exists an Analog Interface 1 (AO1) and an Analog Interface 2 (AO2).

2.4.2 Available Analog Interface Modes

With register 4322, the available analog interface modes for AO1 and AO2 are defined

Start register

Number of registers

Reg1 / Reg2

Reg3 / Reg4

Reg5 / Reg6

Reg7 / Reg8

Modbus function code

Read access

Write access

4322 8 Available

Analog Interface Modes for AO1

Available Analog Interface Modes for AO2

reserved reserved 3,4 U/A/S none

Figure 2.4.2.1: Definition of register 4322. It defines the analog interface modes available for AO1 and

AO2. The analog interface modes are described in Figure 2.4.2.2.

Code (Hex)

Analog Interface Mode

Description

0x00 4-20 mA inactive Analog interface deactivated 0x01 4-20 mA fixed Set to a constant output value for current loop testing 0x02 4-20 mA linear Linear output of measurement (PMC1 / 6) 0x04 4-20 mA bilinear Bilinear output of measurement (PMC1 / 6)

Figure 2.4.2.2: Definition of the analog interface modes, valid for both AO1 and AO2.

Command: Analog Interface Modes

Modbus address: 4322 Length: 8 Type: 3

Read

Parameter: Available Analog

Interface Modes for

AO1

Available Analog Interface Modes for AO2

reserved reserved

Format: Hex Hex Hex Hex Value:

0x07 0x07 0x0 0x0

Figure 2.4.2.3: Example to read register 4322: all modes defined in figure 2.4.2.2 are available for both

AO1 and AO2.

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2.4.3 Description of the Analog Interfaces 1 and 2

Start register

Number of registers

Reg1 … Reg8 16 ASCII characters

Modbus function code

Read access

Write

access 4352 8 Description of AO1 3, 4 U/A/S none 4480 8 Description of AO2 3, 4 U/A/S none

Figure 2.4.2.1: Definition of register 4352 and 4480

Command: Current interface text

Modbus address: 4352 Length: 8 Type: 3

Read Parameter: Text Format: Character Value:

mA interface #1

Figure 2.4.2.2: Example to read the description of AO1. The text is “mA interface #1”. Accordingly,

AO1 is physically configured as a 4-20 mA current output.

Command: Current interface text

Modbus address: 4480 Length: 8 Type: 3

Read Parameter: Text Format: Character Value:

mA interface #2

Figure 2.4.2.3: Example to read the description of AO2. The text is “mA interface #2”. Accordingly,

AO2 is physically configured as a 4-20 mA current output.

Attention:

 pH ARC Sensors do not have an ECS (in contrast to VISIFERM DO)!  Data structure: register address offset between AO1 and AO2 is always 128.

2.4.4 Selection of an Analog Interface Mode

The analog interface mode of AO1 / AO2 is selected by programming the analog interface mode in register 4360 / 4488.

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write

access 4360 2 Active analog interface mode for AO1 3, 4, 16 U/A/S S 4488 2 Active analog interfacemode for AO2 3, 4, 16 U/A/S S

Figure 2.4.4.1: Definition of register 4360 / 4488. Only one bit can be set.

Command: Active interface mode

Modbus address: 4360 Length: 2 Type: 16

Write Parameter: Mode Format: Hex Value:

0x02

Figure 2.4.4.2: Example to set the analog interface mode of AO1 to 0x02 (4-20 mA linear output).

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2.4.5 Configuration of the 4-20 mA Interface

Note: The configuration of AO1 / AO2 is only effective if register 4360 / 4488 (active analog interface mode) is set to the value 0x01, 0x02 or 0x04.

2.4.5.1 Reading the Available Primary Measurement Channels to be Mapped to the Analog Output

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write access

4362 2 Available Primary Measurement Channels

for AO1

3, 4 U/A/S none

4490 2 Available Primary Measurement Channels

for AO2

3, 4 U/A/S none Figure 2.4.5.1.1: Definition of register 4362 / 4490. For the definition of the Primary Measurement Channels (PMC), see chapter 2.5.

Code (Hex)

Primary Measurement Channel (PMC)

0x01 PMC1 (pH)

not available

0x20 PMC6 (temperature)

Figure 2.4.5.1.2: Code for selection of the primary measurement channel.

Command: Available PMC AO1

Modbus address: 4362 Length: 2 Type: 3

Read Parameter: Available PMC 20 mA Format: hex Value:

0x21

Figure 2.4.5.1.3: Example to read the available Primary Measurement Channels (PMC) for AO1. The

hexadecimal value of “0x21”defines that PMC1 (pH) or PMC6 (temperature) can be mapped to AO1. Register 4490 contains the same value “0x21”. Accordingly, PMC1 or PMC6 can be mapped to AO2 as well.

2.4.5.2 Selecting the Primary Measurement Channel to be Mapped to the Analog Interface

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write

access 4364 2 Selected PMC for AO1 3, 4, 16 U/A/S S 4492 2 Selected PMC for AO2 3, 4, 16 U/A/S S

Figure 2.4.5.2.1: Definition of register 4364 / 4492. Only one bit can be set.

Command: Active PMC AO1

Modbus address: 4364 Length: 2 Type: 3

Read Parameter: Current PMC 20mA Format: hex Value:

0x01

Figure 2.4.5.2.2: Example to read the current primary measurement channel mapped to AO1, defined

in register 4364. The value “0x01”is returned, saying that PMC1 is mapped to AO1 (factory setting).

The factory setting for register 4492 is “0x20”, mapping PMC6 to AO2.

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2.4.5.3 Reading the Minimum and Maximum Possible Physical Output Current

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Modbus

function code

Read access

Write access

4366 4 Min physical

output current for AO1 [mA]

Max physical output current for AO1 [mA]

3, 4 U/A/S none

4494 4 Min physical

output current for AO2 [mA]

Max physical output current for AO2 [mA]

3, 4 U/A/S none

Figure 2.4.5.3.1: Definition of register 4366 / 4494

Command: Limits AO1

Modbus address: 4366 Length: 4 Type: 3

Read Parameter: Min limit [mA] Max limit [mA] Format: Float Float Value:

3.5 22

Figure 2.4.5.3.2: Example to read the min and max output current of AO1. Min is fixed to 3.5 and Max

is fixed to 22 mA (Currents above 20 and below 4 mA indicate erroneous measurements or errors). The same values are stored in register 4494 for AO2.

2.4.5.4 Reading the Minimum, Maximum and Mid Current for Measurement Value Output

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Reg5 / Reg6 Modbus

function code

Read access

Write access

4370 6 Min output for

measurement value for AO1 [mA]

Max output for measurement values for AO1 [mA]

Mid output (bilinear) for measurement values for AO1 [mA]

3, 4 U/A/S none

4498 6 Min output for

measurement value for AO2 [mA]

Max output for measurement values for AO2 [mA]

Mid output (bilinear) for measurement values for AO2 [mA]

3, 4 U/A/S none

Figure 2.4.5.4.1: Definition of register 4370 / 4498

Command: MinMaxMid current AO1

Modbus address: 4370 Length: 6 Type: 3

Read Parameter: Min current [mA] Max current [mA] Mid current [mA] Format: Float Float Float Value:

4 20 12

Figure 2.4.5.4.2: Example to read the min, max and mid output current for measurement values for

AO1. They are fixed to 4, 20 and 12 mA.

The same values are stored in register 4498 for AO2.

Note: Mid current must always be defined. However, in linear output mode, the mid current value has no physical meaning and will not affect the 4-20 mA output.

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2.4.5.5 Reading the Selected Physical Unit for Analog Interface

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write access

4376 2 Selected physical unit of AO1

(see chapter 2.5.1)

3, 4 U/A/S none

4504 2 Selected physical unit of AO2

(see chapter 2.5.1)

3, 4 U/A/S none

Figure 2.4.5.5.1: Definition of register 4376 / 4504.

Command: Avail unit AO1

Modbus address: 4376 Length: 2 Type: 3

Read Parameter: Available unit Format: Hex Value:

0x001000

Figure 2.4.5.5.2: Example to read the selected unit of the selected PMC of AO1. The value returned is

“0x001000”, accordingly, the unit is pH. The physical unit for PMC is defined in Reg. 2090 or 2410 and applies automatically for 4-20 mA output.

2.4.5.6 Defining the Measurement Values for 4, 12 and 20 mA Output

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Reg5 / Reg6 Modbus

function code

Read access

Write access

4378 6 Measurement

value at Min Output Current (4 mA) for AO1

Measurement value at Max Output Current (20 mA) for AO1

Measurement value at Mid Output Current (12 mA) for AO1

3, 4, 16 U/A/S S

4506 6 Measurement

value at Min Output Current (4 mA) for AO2

Measurement value at Max Output Current (20 mA) for AO2

Measurement value at Mid Output Current (12 mA) for AO2

3, 4, 16 U/A/S S

Figure 2.4.5.6.1: Definition of register 4378 / 4506.

Command: MinMaxMid value AO1

Modbus address: 4378 Length: 6 Type: 16

Write Parameter: Min value Max value Mid value Format: Float Float Float Value:

3 10 7

Figure 2.4.5.6.2: Example to set the min value to 3 (for 4 mA), the max value to 10 (for 20 mA) and the

mid value to 7 (for 12 mA). The corresponding physical unit can be read in register 4376 / 4504 and in 2090 / 2410.

Note: Mid current must always be defined. However, in linear output mode, the mid current value has no physical meaning and will not affect the 4-20 mA output.

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pH ARC sensor: 4-20mA inte rface - linear

-15

-10

-5

0 4 8 12 16 20 24

Curr ent [mA]

temperature [°C]

Temp [°C] pH

Figure 2.4.5.6.3: Example of linear 4-20 mA output characteristics for pH or temperature.

Current pH Temperature 4 mA 2 -10 °C 20 mA 9 +30 °C

pH ARC sensor: 4-20mA interface - biline ar

-15

-10

-5

0 4 8 12 16 20 24

Current [mA]

temperature [°C]

Temp [°C] pH

Figure 2.4.5.6.4: Example of bilinear 4-20 mA output characteristics for pH or temperature.

Current pH Temperature 4 mA 2 -10 °C 12 mA 9 +20 °C 20 mA 10 +30 °C

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Attention: When assigning measurement values to 4-20 mA analog output by using register 4378 / 4506, you need to consider the following:

 The PMC you have mapped to AO1 / AO2 (register 4364 / 4492)  The physical unit currently in use for the selected PMC (register 2090 for PMC1 (pH) and

register 2410 for PMC6 (temperature). Therefore, when the operator redefines one of the register 4364 / 4492, 2090 / 2410, the definitions of the register 4378 / 4506 should be reviewed. If not, the current output at the 4-20 mA interfaces may be wrong.

Note: The physical unit of the analog output correspondsalways to the unit that is set for the selected PMC (register 2090 for PMC1 or register 2410 for PMC6). Accordingly, not only the pH value is selectable at the 4-20 mA interface, but also mV values, degrees centigrade or Kelvin.

Example: Register 4364 is set to 1 (PMC1 is mapped to AO1). Register 2090 is set to 0x1000 (the unit “pH”is assigned to PMC1). Register 4378 is set to 2 and 10 (4 mA = pH 2, 20 mA = pH 10). The sensor reads currently pH 4, the output at the 4-20 mA is accordingly 8 mA. The operator now re-assigns register 2090 to the value of 0x200000 (unit = mV), but does not modify all other registers. The sensor is still at pH 4 and reads now +170 mV. At the analog output, as 20 mA is programmed to a value of 10 by register 4378, the current will go to the maximum value of 20 mA. This will generate an interface warning “4-20 mA current set point not met”.

2.4.5.7 Defining a Constant Current Output for Testing

Note: For constant current output, the AO1 / AO2 must be set to analog interface mode 0x01:

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write access

4384 2 Constant current output value for

AO1 [mA]

3, 4, 16 U/A/S S

4512 2 Constant current output value for

AO2 [mA]

3, 4, 16 U/A/S S

Figure 2.4.5.7.1: Definition of register 4384 / 4512.

Command: Fixed value AO1

Modbus address: 4384 Length: 2 Type: 3

Read Parameter: Fixed value [mA] Format: Float Value:

Figure 2.4.5.7.2: Example to read the constant current output in mode 0x01 for AO1. It is set to 10 mA.

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2.4.5.8 Defining the Error and Warning Output of the 4-20 mA Interface

Errors and warnings can be mapped to the AO1 / AO2.

Start register

Number of registers

Reg1 / Reg2

Reg3 / Reg4

Reg5 / Reg6

Reg7 / Reg8

Modbus function code

Read access

Write access

4386 8 Code of

warnings and errors (see Figure

2.4.4.8.2) for AO1

Current in case of “warning” [mA] for AO1

Current in case of “error” [mA] for AO1

Current in case of “T exceed” [mA] for AO1

3, 4, 16 U/A/S S

4514 8 Code of

warnings and errors (see Figure

2.4.4.8.2) for AO2

Current in case of “warning” [mA] for AO2

Current in case of “error” [mA] for AO2

Current in case of “T exceed” [mA] for AO2

3, 4, 16 U/A/S S

Figure 2.4.5.8.1: Definition of register 4386 / 4514.

Bit # Code (hex) Behaviour of the 4-20 mA interface in case of errors and warnings 0 (LSB) 0x000001 Error continuous output

not available

16 0x010000 Warning continuous output

not available

Figure 2.4.5.8.2: Code for the 4-20 mA interface in case of errors and warnings. If the corresponding bits for the errors and warnings are not set (=0x00), the respective options are

inactive. The default settings are:

 Code 0x01  current in case of warnings: 3.5 mA  current in case of errors: 3.5 mA  current in case of temperature exceed: 3.5 mA

Command: ErrorWarnings AO1

Modbus address: 4386 Length: 8 Type: 3

Read

Parameter: Warning code Current in case of

warning [mA]

Current in case of error [mA]

Current in case of temperature exceed

[mA] Format: Hex Float Float Float Value:

0x010001 3.5 3.5 3.5

Figure 2.4.5.8.4: Example: Read the settings for AO1 in case of warnings and errors. Warning code

0x010001 corresponds to the continuous output current in case of warning (0x010000) and continuous output current in case of error (0x01) of 3.5 mA. The output current in case of temperature exceed is 3.5 mA.

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2.4.6 Reading the Internally Measured Output Current

Reg. 4414 / 4542 provides internal parameters of AO1 / AO2:

 the setpoint to which the current is regulated in a closed loop control  the electrical current the sensor is measuring to feed the closed loop control

These values are helpful in order to compare against the externally measured electrical current.

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Modbus

function code

Read access

Write access

4414 4 Set point

[mA] AO1

Internally measured [mA] AO1

3, 4 U/A/S none

4542 4 Set point

[mA] AO2

Internally measured [mA] AO2

3, 4 U/A/S none

Figure 2.4.6.1: Definition of register 4414 / 4542.

Command: Internal values AO1

Modbus address: 4414 Length: 4 Type: 3

Read

Parameter: Set point

[mA]

Internally measured

[mA] Format: Float Float Value:

9.99186 9.99742

Figure 2.4.6.2: Example to read the internal values of AO1, depending on the analog interface mode.

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2.5 Measurement

2.5.1 Definition of Measurement Channels and Physical Units

The pH ARC Sensor Modbus register structure allows the definition of 6 individual Primary Measurement Channels (PMC), and 16 individual Secondary Measurement Channels (SMC).

Bit # Hex code Description Definition

0 (LSB) 0x000001 PMC1 pH

1 0x000002 PMC2 not available

not available

4 0x000010 PMC5 not available

5 0x000020 PMC6 Temperature 6 0x000040 SMC1 R glass 7 0x000080 SMC2 R reference 8 0x000100 SMC3 R auxiliary 9 0x000200 SMC4 E pH vs. ref 10 0x000400 SMC5 E SG vs. ref 11 0x000800 SMC6 E aux vs. ref 12 0x001000 SMC7 E reference 13 0x002000 SMC8 pH act 14 0x004000 SMC9 T act

15 0x008000 SMC10 not available

…

21 (MSB) 0x200000 SMC16 not available

Figure 2.5.1.1: full list of PMC1 to 6 and SMC1 to 16. In Register 2048, the available PMC and SMC are defined for a specific pH ARC Sensors and a

specific operator level.

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write access

2048 2 Available measurement channels

PMC and SMC (bitwise set)

3, 4 U/A/S none

Figure 2.5.1.2: Definition of register 2048.

Command: Avail. PMC and SMC

Modbus address: 2048 Length: 2 Type: 3

Read

Parameter: Avail. PMC and

SMC Format: Hex Value: 0x06E1

Figure 2.5.1.3: Example to read Reg. 2048 for Polilyte Plus ARC.

In case of operator A/U, the value 0x06E1 is returned. In other words the following PMC and SMC are available to A/U: PMC1 / PMC6 / SMC1 / SMC2 / SMC4 / SMC5 In case of operator S, the value 0x066E1 is returned. In other words the following PMC and SMC are available to S: PMC1/ PMC6 / SMC1 / SMC2 / SMC4 / SMC5 / SMC8 / SMC9

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The pH ARC Sensor register structure uses the followingphysical units used for Primary or Secondary Measurement Channels.

Bit # Hex code Physical unit Start register. (8 ASCII characters, length 4 registers,

Type 3, read for U/A/S) 0 (LSB) 0x00000001 none 1920 1 0x00000002 K 1924 2 0x00000004 °C 1928 3 0x00000008 °F 1932 4 0x00000010 %-vol 1936 5 0x00000020 %-sat 1940 6 0x00000040 ug/l ppb 1944 7 0x00000080 mg/l ppm 1948 8 0x00000100 g/l 1952 9 0x00000200 uS/cm 1956 10 0x00000400 mS/cm 1960 11 0x00000800 1/cm 1964 12 0x00001000 pH 1968 13 0x00002000 mV/pH 1972 14 0x00004000 kOhm 1976 15 0x00008000 MOhm 1980 16 0x00010000 pA 1984 17 0x00020000 nA 1988 18 0x00040000 uA 1992 19 0x00080000 mA 1996 20 0x00100000 uV 2000 21 0x00200000 mV 2004 22 0x00400000 V 2008 23 0x00800000 mbar 2012 24 0x01000000 Pa 2016 25 0x02000000 Ohm 2020 26 0x04000000 %/°C 2024 27 0x08000000 ° 2028 28 0x10000000 not used 2032 29 0x20000000 not used 2036 30 0x40000000 not used 2040 31 (MSB) 0x80000000 SPECIAL 2044

Figure 2.5.1.4: Definition of physical units used for PMC and SMC.

Command: Unit text

Modbus address: 1968 Length: 4 Type: 3

Read Parameter: Text Format: Character Value:

Figure 2.5.1.5: Example to read the physical unit in plain text ASCII in register 1968

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2.5.2 Primary Measurement Channel 1 (pH)

2.5.2.1 Description of PMC1

In register 2080, a plain text ASCII description of PMC1 is given.

Start register

Number of registers

Reg1 … Reg8 16 ASCII characters

Modbus function code

Read access

Write access

2080 8 Description of PMC1 3, 4 U/A/S none

Figure 2.5.2.1.1: Definition of register 2080.

Command: PMC 1 text

Modbus address: 2080 Length: 8 Type: 3

Read Parameter: Text Format: Character Value:

Figure 2.5.2.1.2: Example to read the description. It is “pH”.

2.5.2.2 Selecting the Physical Unit for PMC1

In register 2088, the available physical units for this channel are defined.

Start register

Number of registers

Reg1 / Reg2 (bitwise defined)

Modbus function code

Read access

Write access

2088 2 Available physical units of PMC1 3, 4 U/A/S none

Figure 2.5.2.2.1: Definition of register 2088.

Command: PMC1 available units

Modbus address: 2088 Length: 2 Type: 3

Read Parameter: Units Format: Hex Value:

0x201000

Figure 2.5.2.2.2: Example to read the available physical units of PMC1: pH (0x001000) + mV

(0x200000), total 0x201000.

In register 2090, the active physical unit for this channel can be selected, by choosing one of the physical units that are defined in register 2088.

Start register

Number of registers

Reg1 / Reg2 (bitwise defined)

Modbus function code

Read access

Write access

2090 2 Selected active physical unit for the

PMC1

16 none S

Figure 2.5.2.2.3: Definition of register 2090. Only one bit can be set.

Command: PMC1 set unit

Modbus address: 2090 Length: 2 Type: 16

Write Parameter: Unit Format: Hex Value:

0x1000

Figure 2.5.2.2.4: Example to set the physical unit of PMC1 to pH (0x1000).

Attention: Changing the physical unit has also an influence on the output of AO1 / AO2, as the same physical unit is active for the analog outputs. All limits of the 4-20 mA analog output have to be redefined after changing the physical unit!

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2.5.2.3 Reading the measurement value of PMC1

Start reg.

Number of reg.

Reg1 / Reg2

Reg3 / Reg4

Reg5 / Reg6

Reg7 / Reg8

Reg9 / Reg10

Modbus function code

Read access

Write access

2090 10 Selected

physical unit

Measure

-ment value of PMC1

(1)

Measure

-ment status

(2)

Min allowed value

(1)

Max allowed value

(1)

3, 4 U/A/S none

Figure 2.5.2.3.1: Definition of register 2090. Measurement value of PMC1.

(1)

Value is always in the physical unit defined in register 2090.

(2)

Definition of the status see chapter 2.5.4. All bits set to zero means: no problem.

Command: PMC1 read

Modbus address: 2090 Length: 10 Type: 3

Read Parameter: Unit Value Status Min limit Max limit Format: Hex Float Hex Float Float Value:

0x1000 4.02503 0x00 0 14

Figure 2.5.2.3.2: Example to read register 2090. Physical unit is set to pH (0x1000), PMC1 is pH

4.02503, Status is 0x00, Min allowed value is pH 0, Max allowed value is pH 14.

Command: PMC1 read

Modbus address: 2090 Length: 10 Type: 3

Read Parameter: Unit Value Status Min limit Max limit Format: Hex Float Hex Float Float Value:

0x200000 175.9922 0x00 0 954.6541

Figure 2.5.2.3.3: Example to read register 2090. Physical unit is set to mV (0x200000), PMC1 is

175.9922 mV, Status is 0x00, Min allowed value is -414.0028 mV, Max allowedvalue is

414.0028 mV.

For the definition of the measurement status see chapter 2.5.4.

Attention: You cannot read selectively the registers 3 and 4 for the measurement value only. You have to read the entire length of the command (10 registers) and extract the desired information.

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2.5.3 Primary Measurement Channel 6 (Temperature)

2.5.3.1 Description of PMC6

In register 2400, a plain text ASCII description of PMC6 is given

Start register

Number of registers

Reg1 … Reg8 16 ASCII characters

Modbus function code

Read access

Write access

2400 8 Description of PMC6 3, 4 U/A/S none

Figure 2.5.3.1.1: Definition of register 2400.

Command: PMC6 text

Modbus address: 2400 Length: 8 Type: 3

Read Parameter: Text Format: Character Value:

Figure 2.5.3.1.2: Example to read the description. It is “T”(Temperature).

2.5.3.2 Selecting the Physical Unit for PMC6

In register 2408, the available physical units of PMC6 are defined.

Start register

Number of registers

Reg1 / Reg2 (bitwise defined)

Modbus function code

Read access

Write access

2408 2 Available physical units of PMC6 3, 4 U/A/S none

Figure 2.5.3.2.1: Definition of register 2408.

Command: PMC6 available units

Modbus address: 2408 Length: 2 Type: 3

Read Parameter: Units Format: Hex Value:

0x06

Figure 2.5.3.2.2: Example to read the available physical unit for PMC6. K (0x02) + °C (0x04), total

0x06.

In register 2410, the active physical unit of PMC6 can be selected, by choosing one of the physical units that are defined in register 2408.

Start register

Number of registers

Reg1 / Reg2 (bitwise defined)

Modbus function code

Read access

Write access

2410 2 Selected active physical unit of PMC6 16 none U/A/S

Figure 2.5.3.2.3: Definition of register 2410. Only one bit can be set.

Command: PMC6 set unit

Modbus address: 2410 Length: 2 Type: 16

Write Parameter: Unit Format: Hex Value:

0x04

Figure 2.5.3.2.4: Example to set the physical unit of PMC6 to °C (0x04).

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2.5.3.3 Reading the measurement value of PMC6

Start reg.

Number of reg.

Reg1 / Reg2

Reg3 / Reg4

Reg5 / Reg6

Reg7 / Reg8

Reg9 / Reg10

Modbus function code

Read access

Write access

2410 10 Selected

physical unit

Measure

-ment value of PMC6

(1)

Measure

-ment status

(2)

Min allowed value

(1)

Max allowed value

(1)

3, 4 U/A/S none

Figure 2.5.3.3.1: Definition of register 2410. Measurement value of PMC6.

(1)

Value is always in the physical unit defined in register 2410.

(2)

For definition of the status see chapter 2.5.4. All bits set to zero means: no problem.

Command: PMC6 read

Modbus address: 2410 Length: 10 Type: 3

Read Parameter: Unit Value Status Min limit Max limit Format: Hex Float Hex Float Float Value:

0x04 24.35834 0x00 -20 130

Figure 2.5.3.3.2: Example to read register 2410. Physical unit is set to °C (0x04), PMC6 is 24.35834

°C, Status is 0x00, Min allowed value is -20 °C, Max allowed value is 130 °C.

For definition of the measurement status see chapter 2.5.4.

Attention: You cannot read selectively the registers 3 and 4 for the measurement value only. You have to read the entire length of the command (10 registers) and extract the desired information.

2.5.3.4 Input of an Externally Measured Temperature

Unlike to the VISIFERM DO, this feature is not available for pH ARC Sensors.

2.5.4 Definition of the Measurement Status for PMC1 / PMC6

This is the definition of the status registers read in registers 2090 (PMC1) and 2410 (PMC6):

Bit # Hex code Description 0 (LSB) 0x01 Temperature out of measurement range (see chapter 2.8.1) 1 0x02 Temperature out of operating range (see chapter 2.8.1) 2 0x04 Calibration status not zero (see chapter 2.7.4) 3 0x08 Warning not zero (see chapter 2.8.3) 4 0x10 Error not zero (see chapter 2.8.4)

Figure 2.5.4.1: Definition of measurement status for Primary Measurement Channels.

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2.5.5 Secondary Measurement Channels 1-16

pH ARC Sensors do allow access to secondary measurement values (16 in total). The access to the individual SMC depends on the operator level. The available SMC are defined in register 2048 according to the selected operator level and the sensor type (see chapter 2.5.1).

2.5.5.1 Description of SMC

The registers defined here give a plain text ASCII description of each available SMC.

Start register

Number of registers

Reg1 … Reg8 16 ASCII characters

Modbus function code

Read access

Write access

Address 8 Description of each SMC 3, 4 U/A/S none

Figure 2.5.5.1.1: Definition of registers at Address

Description Address Plain Text

(16 ASCII)

Description SMC1 2464 R glass Resistance of the pH glass SMC2 2496 R reference Resistance of the reference electrode SMC3 2528 R auxiliary Resistance of the auxiliary electrode SMC4 2560 E pH vs. ref Electrical potential between glass and reference electrode SMC5 2592 E SG vs. ref Electrical potential between solution ground and reference

electrode SMC6 2624 E aux vs. ref Electrical potential between auxiliary electrode and reference

electrode SMC7 2656 E reference Electrical potential between reference electrode and electrical

ground SMC8 2688 pH act Current pH value (3-seconds-reading)

SMC9 2720 T act Current T value (3-seconds-reading)

Figure 2.5.5.1.2: Full list of starting register addresses for the plain text ASCII description of each SMC Example:

Command: SMC 1 text

Modbus address: 2464 Length: 8 Type: 3

Read Parameter: Text Format: Character Value:

R glass

Figure 2.5.5.1.3: Example to read the description of SMC1 at address 2464. It is “R glass”.

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2.5.5.2 Reading the measurement value of SMC

The registers defined here are used to read the measurementvalues of each SMC.

Start reg. Num-

ber of reg.

Reg1 / Reg2 Reg3 / Reg4 Reg5 / Reg6 Modbus

function code

Read access

Write access

Address 6 Physical unit Measurement

value of SMC

Standard deviation

3, 4 U/A/S none

Figure 2.5.5.2.1: Definition of register at Address. Measurement value of each SMC.

Description Address Text Unit Min value Max value SMC1 2472 R glass MOhm 30 600 SMC2 2504 R reference kOhm 0.25 100 SMC3 2536 R auxiliary kOhm 0.25 100 SMC4 2568 E pH vs. ref mV -900 900 SMC5 2600 E SG vs. ref mV -900 900 SMC6 2632 E aux vs. ref mV -50 50 SMC7 2664 E reference mV -900 900 SMC8 2696 pH act pH -0.5 14 SMC9 2728 T act K 253 403

Figure 2.5.5.2.2: Full list of register addresses for the measurement values of SMC1 to SMC9 Example:

Command: SMC1 read

Modbus address: 2472 Length: 6 Type: 3

Read Parameter: Unit Value Standard dev. Format: Hex Float Float Value:

0x8000 247.56 0.02

Figure 2.5.5.2.3: Example to read register 2472. Physical unit is MOhm (0x8000), the measurement

value of SMC1 is 247.66 MOhm, standard deviation of SMC1 is 0.02 MOhm

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2.6 Configuration of the Measurement

This chapter describes the configuration of PMC1 and PMC6 by means of measurement parameters (PA).

2.6.1 Available Parameters

In register 3072, all available parameters (PA) are given.

Start register

Number of registers

Reg1 / Reg2 (bitwise defined)

Modbus function code

Read access

Write access

3072 2 Available parameters (see figure 2.6.1.2) 3, 4 U/A/S none

Figure 2.6.1.1: Definition of register 3072.

Bit # Hex value Description Definition in pH ARC Sensors 0 (LSB) 0x0001 PA1 not available

not available

7 0x0080 PA8 not available

8 0x0100 PA9 Moving average

9 0x0200 PA10 not available 10 0x0400 PA11 not available

11 0x0800 PA12 Moving average R

not available

15 (MSB) 0x8000 PA16 not available

Figure 2.6.1.2: Bitwise definition of parameters PA1 to PA16, valid for pH ARC Sensors

Command: Available parameters

Modbus address: 3072 Length: 2 Type: 3

Read

Parameter: Measurement

parameters Format: Hex Value:

0x0900

Figure 2.6.1.3: Example to read the available parameters. The value 0x0900 corresponds to 0x0100

(PA9) + 0x0800 (PA12). Parameter 9 and 12 are available.

Genereal note:

 PA1 to PA8 use FLOAT as data format for its values  PA9 to PA16 use UNSIGNED INT as data format for its values.

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2.6.2 PA9: Moving Average

The pH ARC Sensor provides new pH readings every 3 seconds. One has the possibility to smoothen the pH reading (PMC1) by means of a moving average applied to the 3-seconds-readings.

PA9 can be applied on 1 to 16 3-seconds-readings. The default value is 2.

Effect of Moving Average (n=1 vs n=16)

2.5

3.5

4.5

5.5

15:46

15:47

15:48

15:49

15:50

tim e

mov av = 1 mov av = 16

Effect of Moving Average (n=1 vs n=16)

5.1

5.12

5.14

5.16

5.18

5.2

15:46

15:47

15:48

15:49

15:50

tim e

mov av = 1 mov av = 16

Figure 2.6.2.1: Comparison of the response of a pH ARC Sensor to a change from pH 5.1 to pH 2.5,

using no moving average (n=1) or a moving average over 16 3-seconds-readings.

Using moving average, the short term signal stability can be improved; on the other hand, the response time of the sensor increases with increasing moving average. A moving average over 16 samples results in a response time of at least 48 s.

Note:

 PA9 is applied to both PMC1 and PMC6.

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2.6.2.1 Description of PA9 (Moving Average)

In register 3360, a plain text ASCII description of PA9 is given.

Start register

Number of registers

Reg1 … Reg8 16 ASCII characters

Modbus function code

Read access

Write access

3360 8 Description of PA9 3, 4 U/A/S none

Figure 2.6.2.1.1: Definition of register 3360.

Command: Moving average text

Modbus address: 3360 Length: 8 Type: 3

Read Parameter: Text Format: Character Value:

Moving average

Figure 2.6.2.1.2: Example to read the description for “Moving average“.

2.6.2.2 Selecting the Physical Unit and Writing the Value for PA9

In register 3368, the available physical units for PA9 are defined.

Start register

Number of registers

Reg1 / Reg2 (bitwise defined)

Modbus function code

Read access

Write access

3368 2 Available physical units for PA9 3, 4 U/A/S none

Figure 2.6.2.2.1: Definition of register 3368.

Command: Moving average av. units

Modbus address: 3368 Length: 2 Type: 3

Read Parameter: Units Format: Hex Value:

0x01

Figure 2.6.2.2.2: Example to read the available physical units for PA9. The only one available here is

“none”(0x01). For the definition of the physical units see chapter 2.5.1.

Start register

Number of registers

Reg1 / Reg2 (bitwise defined)

Reg3 / Reg4 Modbus

function code

Read access

Write access

3370 4 Select physical unit

for PA9

Value for PA9 (1-16, default: 2)

16 none S

Figure 2.6.2.2.3: Definition of register 3370. Only one bit for the physical unit can be set. PA9 can be

set to the value 1-16. A value of 1 does not influence the response time of the sensor, a value of 16 increases the response time of the sensor to 48 s.

By writing to register 3370 the active physical unit for PA9 can be selected by choosing one of the physical units that are defined in register 3368. The value of the parameter can be set as well.

Command: Moving average

Modbus address: 3370 Length: 4 Type: 16

Write Parameter: Unit Value Format: Hex Decimal Value:

0x01 12

Figure 2.6.2.2.4: Example to set the physical unit of PA9 to “none”(0x01) and the value of the moving

average to 12.

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2.6.2.3 Reading all Values for PA9

By reading register 3370, the active physical unit of measurement, the selected value, and the min and max values can be read.

Start register

Number of registers

Reg1 / Reg2

Reg3 / Reg4

Reg5 / Reg6

Reg7 / Reg8

Modbus function code

Read access

Write access

3370 8 Physical

unit

Current value

Min value

Max value

3, 4 U/A/S none

Figure 2.6.2.3.1: Definition of register 3370.

Command: Moving average

Modbus address: 3370 Length: 8 Type: 3

Read Parameter: Unit Value Min value Max value Format: Hex Decimal Decimal Decimal Value:

0x01 10 1 16

Figure 2.6.2.3.2: Example to read PA9. The physical unit is 0x01 (“none”), the value is 10 and the limit

is 1 to 16.

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2.6.3 PA12: Moving Average R

pH ARC Sensors allow to have a separate moving average on secondary measurement values:

 Glass resistance  Reference resistance

The moving average can be applied on 1 to 16 3-s measurement values. The default value is 4. Especially if high resistances are measured, it is recommended to choose a higher moving average.

2.6.3.1 Description of PA12 (Moving Average R)

In register 3456, a plain text ASCII description of PA12 is given.

Start register

Number of registers

Reg1 … Reg8 16 ASCII characters

Modbus function code

Read access

Write access

3456 8 Description of PA12 3, 4 U/A/S none

Figure 2.6.3.1.1: Definition of register 3456.

Command: Moving average text

Modbus address: 3456 Length: 8 Type: 3

Read Parameter: Text Format: Character Value:

Moving average R

Figure 2.6.3.1.2: Example to read the description for “Moving average R“.

2.6.3.2 Selecting the Physical Unit and Writing the Value for PA12

In register 3464, the available physical units for PA12 are defined.

Start register

Number of registers

Reg1 / Reg2 (bitwise defined)

Modbus function code

Read access

Write access

3464 2 Available physical units for PA12 3, 4 U/A/S none

Figure 2.6.3.2.1: Definition of register 3368.

Command: Moving average av. units

Modbus address: 3464 Length: 2 Type: 3

Read Parameter: Units Format: Hex Value:

0x01

Figure 2.6.3.2.2: Example to read the available physical units for PA12. The only one available here is

“none”(0x01). For the definition of the physical units see chapter 2.5.1.

Start register

Number of registers

Reg1 / Reg2 (bitwise defined)

Reg3 / Reg4 Modbus

function code

Read access

Write access

3466 4 Select physical unit

for PA12

Value for PA12 (1-16, default: 4)

16 none S

Figure 2.6.3.2.3: Definition of register 3466. Only one bit for the physical unit can be set. PA12 can be

set to the values 1-16.

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By writing to register 3466, the active physical unit for PA12 can be selected, by choosing one of the physical units that are defined in register 3464. The value of the parameter can be set as well.

Command: Moving average

Modbus address: 3466 Length: 4 Type: 16

Write Parameter: Unit Value Format: Hex Decimal Value:

0x01 7

Figure 2.6.3.2.4: Example to set the physical unit of PA12 to “none”(0x01) and the value of the moving

average R to 7.

2.6.3.3 Reading all Values for PA12

By reading register 3466, the active physical unit of measurement, the selected value, and the min and max values can be read.

Start register

Number of registers

Reg1 / Reg2

Reg3 / Reg4

Reg5 / Reg6

Reg7 / Reg8

Modbus function code

Read access

Write access

3466 8 Physical

unit

Current value

Min value

Max value

3, 4 U/A/S none

Figure 2.6.3.3.1: Definition of register 3466.

Command: Moving average

Modbus address: 3466 Length: 8 Type: 3

Read Parameter: Unit Value Min value Max value Format: Hex Decimal Decimal Decimal Value:

0x01 7 1 16

Figure 2.6.3.3.2: Example to read PA12. The physical unit is 0x01 (“none”), the value is 7, and the

limits are 1 to 16.

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2.7 Calibration

2.7.1 Available Calibration Points

In register 5120, the available number of Calibration Points (CP) for Primary Measurement Channel 1 (PMC1) is defined. 8 individual CP are theoretically possible.

Start register

Number of registers

Reg1 / Reg2 (bitwise defined)

Modbus function code

Read access

Write access

5120 2 Available number of CP for PMC1

(see figure 2.7.1.2)

3, 4 U/A/S none

Figure 2.7.1.1: Definition of register 5120.

Bit # Hex value Description Definition in ARC Sensors

0 (LSB) 0x01 CP1 Calibration Point 1 1 0x02 CP2 Calibration Point 2

2 0x04 CP3 not available … … … not available

5 0x20 CP6 Product Calibration

6 0x40 CP7 not available 7 (MSB) 0x80 CP8 not available

Figure 2.7.1.2: Bitwise definition of CP1 to CP8.

Command: Available cali points

Modbus address: 5120 Length: 2 Type: 3

Read Parameter: Points Format: Hex Value:

0x23

Figure 2.7.1.3: Example to read the available CPs. 0x23 = 0x01 (CP1) + 0x02 (CP2) + 0x20 (CP6).

Standard Calibration at 2 calibration points

-200

-150

-100

-50

100

150

200

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH value

electrical potential glass vs. ref [mV]

CP2

CP1

Figure 2.7.1.4: pH ARC Sensors allow 3 calibration points:

CP1 and CP2 are used for standard calibration (shown in this figure). The product calibration CP6 is used to adjust the standard calibration function to specific process conditions (the effect of CP6 is shown in Figure 2.7.3.2.1).

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2.7.2 Definitions of Calibration Points

2.7.2.1 Calibration Points 1 and 2 (Standard Calibration)

The limits for the calibration point 1 are defined in register 5152, for calibration point 2 in register 5184.

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Reg5 / Reg6 Modbus

function code

Read access

Write access

5152 6 Physical unit

currently active for CP1

Min value for CP1 (in the physical unit as defined in Reg1 and 2)

Max value for CP1 (in the physical unit as defined in Reg1 and 2)

3, 4 U/A/S none

5184 6 Physical unit

currently active for CP2

Min value for CP2 (in the physical unit as defined in Reg1 and 2)

Max value for CP2 (in the physical unit as defined in Reg1 and 2)

3, 4 U/A/S none

Figure 2.7.2.1.1: Definition of register 5152 for CP1 and 5184 for CP2.

Attention: The only physical unit available for calibration is pH ! The physical unit defined in 5152, 5184 and 5312 for CP1, CP2 and CP6 is NOT linked to the physical unit defined for PMC1 in register 2090. When performing a calibration while having the physical unit set to “mV”, the calibration status will report “CP1: incorrect measurement unit”or “CP2: incorrect measurement unit”(see figure 2.7.4.1.1).

Command: Calibration limits CP1

Modbus address: 5152 Length: 6 Type: 3

Read Parameter: Unit Min value Max value Format: Hex Float Float Value:

0x01000 0 0

Figure 2.7.2.1.2: Example to read the limits of CP1. Currently active physical unit is pH (0x01000). The

min and max values are both 0, indicating, that calibration at CP1 can be performed only using defined calibration standards having discrete pH values.

Command: Calibration limits CP2

Modbus address: 5184 Length: 6 Type: 3

Read Parameter: Unit Min value Max value Format: Hex Float Float Value:

0x01000 0 0

Figure 2.7.2.1.3: Example to read the limits of CP2. The active physical unit is is pH (0x01000). The

min and max values are both 0, indicating, that calibration at CP2 can be performed only using defined calibration standards having discrete pH values.

When initiating the calibration at CP1 and CP2, the measured pH and temperature have to be stable for at least 3 minutes. The stability criteria are defined in register 5128:

Start register

Number of registers

Reg1 / Reg2 (Float)

Reg3 / Reg4 (Float)

Modbus function code

Read access

Write access

5128 4 Max. Drift PMC1

pH [pH/min]

Max. Drift PMC6 Temperature [K/min]

3, 4, 16 U/A/S S

Figure 2.7.2.1.4: Definition of register 5128.

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Command: Read calibration stability

Modbus address: 5128 Length: 4 Type: 3

Read

Parameter: Max drift pH

[pH/min]

Max drift Temp

[K/min] Format: Float Float Value:

0.1 0.5

Figure 2.7.2.1.5: Example to read the calibration stability.

Command: Set calibration stability

Modbus address: 5128 Length: 4 Type: 16

Write

Parameter: Max drift pH

[pH/min]

Max drift Temp

[K/min] Format: Float Float Value:

0.2 0.5

Figure 2.7.2.1.6: Example to set the calibration stability.

Attention:

The stability criteria defined in register 5128 is valid for CP1 and CP2 only, but NOT for CP6.

2.7.2.2 Calibration Point 6 (Product Calibration)

The limits for calibration point 6 are given in register 5312.

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Reg5 / Reg6 Modbus

function code

Read access

Write access

5312 6 Physical unit

currently active for CP6

Min value for CP6 (in the physical unit as defined in Reg1 and 2)

Max value for CP6 (in the physical unit as defined in Reg1 and 2)

3, 4 U/A/S none

Figure 2.7.2.2.1: Definition of register 5312 for CP6.

Command: Calibration limits CP6

Modbus address: 5312 Length: 6 Type: 3

Read Parameter: Unit Min value Max value Format: Hex Float Float Value:

0x01000 0 14

Figure 2.7.2.2.2: Example to read the limits of CP6. The active physical unit is pH, the min value is pH

0 and the max value is pH 14.

Note: the definition of min and max is different than the one for CP1 / CP2, because CP6 can be

set to any pH value.

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2.7.3 Calibration Procedure

2.7.3.1 Calibration at CP1 and CP2 (Standard Calibration)

The ARC Sensor family has a unique calibration routine. When initiating the calibration, the data set of the sensor is automatically traced back within the last 3 minutes and a decision is made immediately if the calibration is successful or not. The operator therefore gets an immediate result. The criteria for a successful calibration are:

 the stability of pH value and temperature over the last 3 minutes (see register 5128)  the currently measured pH value fits to one of the calibration standards defined in the selected

set of calibration standards

 the limits of slope and offset at pH 7 have to be met

Standard Calibration at 2 calibration points

-200

-150

-100

-50

100

150

200

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH value

electrical potential glass vs. ref [mV]

CP2

CP1

Figure 2.7.3.1.1: Standard Calibration using CP1 and CP2.

CP1 and CP2 define a linear relationship between the electrical potential and the pH value. This linear calibration function is defined by an offset at pH 7 [mV] and a slope [mV/pH]. These two values are stored in register 5448. Note: the pH value of CP1 can be lower or higher than the pH value of CP2. However, the difference in pH between CP1 and CP2 must always be greater than 1 pH unit.

Notes:

 In order to perform a standard calibration at CP1 and CP2, it is necessary to use commercially

available calibration standards. The operator is restricted to use those standards that are defined in the six sets of calibration standards (see chapter 2.7.11).

 There are two ways of performing a standard calibration:

- standard calibration with automatic recognition of the calibration standard: in this case, the sensor decides on itself in what calibration standard it is immersed. The criteria to decide on is the electrical potential measured. The sensor checks the list of calibration standardsthat are available for automatic recognition (see chapter

2.7.11)

- standardcalibration with manual selection of the calibration standard: the operator is selecting the calibration standard in which the sensor is immersed.

 Factory calibration is pH 4 at CP1 and pH 7 at CP 2.

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Standard Calibration with Automatic Recognition of the Standard

Prior to calibration, the specialist selects - for each set of calibration standards - a list of calibration standards allowed for automatic recognition (register 9530). When the calibration is initiated, the sensor screens this list of allowed calibration standards and checks if the currently measured electrical potential is within the allowed range of electrical potentials, defined for the individual calibration standards in this list.

If the sensor does find a corresponding calibration standard, the nominal pH value of the specific calibration standard is assigned to the currently measured electrical potential. The temperature dependency of the calibration standard is considered during the assignment.

Tempera tue dependen cy of Hamilton p H buffer so lutions

0 10 20 30 40 50 60

Temper ature [°C]

Figure 2.7.3.1.2: Temperature dependency of the pH value of HAMILTON DURACAL calibration

standards.

If the sensor does not find any corresponding calibration standard, the bit representing the corresponding status “no matching calibration standard”is set in the calibration status register.

Note that only the nominal value of the calibration standard is used for calibration. The actual value of the calibration solution, which may deviate from the nominal value, is not taken into account and cannot be set by the operator.

Standard Calibration with Manual Selection of the Calibration Standard

If the operator knows in what calibration standard the sensor is immersed, he can initiate the calibration procedure by means of setting the pH value to the actual value of the calibration standard. The sensor now screens the list of calibration standards that are allowed for manual selection (register 9530). If the pH value entered by the operator fits in the allowed pH range of one of the allowed calibration standards, the entered pH value is assigned to the currently measured electrical potential. The temperature dependency of the calibration standard is considered during the assignment.

If the sensor does not find any corresponding calibration standard, the bit representing the corresponding status “no matching calibration standard”is set in the calibration status register.

Note: using manual selection only, the actual pH value of the calibration standard can be set. However, the actual value must be within the given tolerance of the standard in use.

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Perform the following steps to do a standard calibration at CP1 and CP2:

Step1: Select the desired set of calibration standards (see chapter 2.7.11)

Step 2: Immerse the sensor into one of the calibration standards available in the selected set

Attention:

It is important that the pH ARC Sensor is immersed in a defined calibration standard at least 3 minutes BEFORE the calibration is started.

Step 3: Choose one of the calibration points CP1 or CP2.

Attention:

The assignment of both CP1 and CP2 to the same pH value is rejected. Try to avoid the following situations:

For example, the sensor was calibrated earlier at pH 4 (CP1) and at pH 7 (CP2):

 You want to perform a new calibration at CP1: it is possible to assign CP1 to pH 4 or to

pH 10, but not to pH 7 (already used for CP2).

 You want to perform a new calibration at CP2: it is possible to assign CP2 to pH 7 or

pH 10, but not to pH 4 (already used for CP1).

 If you calibrate now CP1 at pH 10, pH 4 will later be free for selection at CP2. In this

case you can calibrate CP2 at pH 4 or pH 7, but not at pH 10 (CP1).

Step 4: Start the calibration (automatic recognition or manual selection)

The calibration is initiated at CP1 by writing to register 5162 or at CP2 by writing to register 5194.

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write

access 5162 2 pH value at CP1 (unit is always pH) 16 none A/S 5194 2 pH value at CP2 (unit is always pH) 16 none A/S

Figure 2.7.3.1.3: Definition of register 5162 and 5194. You have two options to enter the pH value:

Automatic recognition: pH value=0: the sensor tries to assign the measured electrical potential to

one of the calibration standards available for automatic calibration.

Manual selection: enter the actual pH value at 25°C (the value must be within the tolerance

range of the nominal value of one of the calibration standardsavailable for manual selection)

Step 5: Read the calibration status (seechapter 2.7.4)

Step 6: Check the pH ARC Sensor’s quality indicator

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Examples: (Definitionsof register 5158 and 5190 used in these examples are given in chapter 2.7.4.1, those for register 4872 in chapter 2.8.6)

Example to calibrate at CP1 with automatic recognition:

Command: Make calibration CP1

Modbus address: 5162 Length: 2 Type: 16

Write Parameter: pH value Format: Float Value:

Figure 2.7.3.1.4: Example to start the calibration at CP1, setting a value of 0 for automatic

recognition of the calibration standard.

Example to calibrate at CP2 with automatic recognition:

Command: Make calibration CP2

Modbus address: 5194 Length: 2 Type: 16

Write Parameter: pH value Format: Float Value:

Figure 2.7.3.1.5: Example to start the calibration at CP2, setting a value of 0 for automatic

recognition of the calibration standard.

Example to read the calibration status of CP1:

Command: Calibration status CP1

Modbus address: 5158 Length: 6 Type: 3

Read Parameter: Status Unit Value Format: Hex Hex Float Value:

0x00000000 0x00001000 4.01

Figure 2.7.3.1.6: Example to read the calibration status of CP1 after calibration CP1 at 0 = auto.

All bits of CP1 are zero (0x00000000), indicating that the calibration was successful. The physical unit of the last calibration is pH (0x00001000) and the assigned pH value is 4.01 at 25°C.

Example to read the calibration status of CP2:

Command: Calibration status CP2

Modbus address: 5190 Length: 6 Type: 3

Read Parameter: Status Unit Value Format: Hex Hex Float Value:

0x00000000 0x00001000 7

Figure 2.7.3.1.7: Example to read the calibration status of CP2 after calibrating CP2 at 0 = auto.

All bits of CP2 are zero (0x00000000), indicating that the calibration was successful. The physical unit of the last calibration is pH (0x00001000) and the pH value is 7.

Example to calibrate at CP1 with manual selection of the calibration standard:

Command: Make calibration CP1

Modbus address: 5162 Length: 2 Type: 16

Write Parameter: pH value Format: Float Value:

4.00

Figure 2.7.3.1.8: Example to start the calibration at CP1, by means of manually selecting the

calibration standard HAMILTON DURACAL 4.01 (nominal value 4.01). The operator knows from the certificate of the specific production lot that the actual pH value is 4.00.

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Example to read the sensor’s quality indicator:

Command: Quality indicator

Modbus address: 4872 Length: 2 Type: 3

Read Parameter: Quality [%] Format: Float Value:

100

Figure 2.7.3.1.9: Example to read the sensor’s quality indicator

2.7.3.2 Calibration at CP6 (Product Calibration)

The product calibration is a process in order to adjust the measurement of a correctly calibrated pH ARC Sensor to specific process conditions. Product calibration is a two stage process:

1. An initial measurement is performed while the operator takes a sample of the process solution. At that time point the pH ARC Sensor stores its raw measurement value, temperature and operating hour in the memory.

While the operator takes the sample to the analytics lab for reference analysis the pH ARC Sensor is still running on its prior standard calibration (CP1 and CP2) while the initial measurement data for the ongoing product calibration is kept in the sensor’s memory.

2. When the result of the reference analysis is available this value is assigned, at a second time point, to the former initial measurement data stored in the pH ARC Sensor.

The sensor is now, after valid assignment, running on a calibration function which is compensated for the correct process conditions. The product calibration (CP6) is now active.

Performing a Cancel command for the product calibration (CP6) brings the sensor back to its still stored standard calibration (CP1 and CP2).

If a product calibration is still active and a standard calibration (CP1 or CP2) is performed the product calibration (CP6) is cancelled.

If the operator needs to overrun an active product calibration (old CP6) by a new product calibration (new CP6) the above process applies in the same way. After initial measurement the pH ARC Sensor is still running on the first product calibration (old CP6) until a valid assignment has been done (new CP6).

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What happens to the pH ARC Sensor’s calibration function upon product calibration (CP6)? A product calibration adds an offset to the linear calibration function defined by the standard calibration at CP1 and CP2.

Product calibration of ARC pH sensors

-200

-150

-100

-50

100

150

200

5 6 7 8 9 10

Electrical potential [mV]

Standard Calibration function

Product Calibration function

CP1

CP2

CP6

Figure 2.7.3.2.1: Effect of the product calibration CP6 on an existing standard calibration function

defined by CP1 and CP2.

The operator starts with a Standard Calibration with calibration points CP1 and CP2: CP1: pH value of calibration standard: 6 electrical potential: 64.2 mV

CP2: pH value of calibration standard: 9.21 electrical potential: -125.2 mV The sensor internally calculates the calibration function, using the calibration points CP1 and CP2. The resulting calibration function, compensated to the standard temperature 25°C, is shown as a straight line. The calibration function is described by two parameters: the offset at pH 7 and the slope. Some weeks later, the operator believes that the Standard Calibration function is not correct anymore. As the process is running and he is not able to perform a standard calibration under defined conditions in the lab, he decides to perform a product calibration CP6, in other words adjusting the standard calibration function to the process conditions:

CP6: pH value of product: 7.2 electrial potential: 5 mV The sensor internally adds an offset to the calibration curve. The slope remains unchanged.

Another special feature of this calibration point is to switch off and back on again a product calibration. These functions are called “restore standard calibration”and “restore product calibration”.

Note: The sensor’s internal criteria for a successful product calibration are:

 the sensor is currently in an environment corresponding to the pH ARC Sensors measurement

range.

 the manually assigned pH value does not deviate more than 2 pH units from the value

measured prior the product calibration

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The different functionalities of product calibration (CP6) are accessible through the following sensor commands:

 Initial measurement  Assignment  Cancel  Restore standard calibration  Restore product calibration

All commands are executed by writing a command value to the register 5340 except for assignment where the calibration value is written to register 5322 (see below).

Definition of the commands for product calibration

The commands for register 5340 are defined as follows:

Code Hex Definition of commands 0x01 Perform initial measurement 0x02 Cancel an active product calibration 0x03 Restore a standard calibration from an active product calibration 0x04 Restore a product calibration from an active standard calibration

Figure 2.7.3.2.2: Definition of the commands related to the product calibration

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write access

5340 2 Code as defined in Figure 2.7.3.2.2 3, 4, 16 A/S A/S

Figure 2.7.3.2.3: Definition of register 5340

2.7.3.2.1 Product calibration: Initial measurement

Upon process sample collection for laboratory analysis the command for initial measurement is sent to the sensor. This is achieved by writing the command 0x01 to register 5340 which performs the initial measurement and stores the corresponding measurementvalues in the sensor.

Command: CP6: Initial measurement

Modbus address: 5340 Length: 2 Type: 16

Write Parameter: Command Format: Hex Value:

0x01

Figure 2.7.3.2.1.1: Example to start the product calibration procedure. Writing the command code 0x01

(initial measurement) to the CP6 command register 5340.

After successful initial measurement the corresponding calibration status (register 5318, figure

2.7.4.2.1) is “CP6 initial measurement”(0x08000000) (see figure 2.7.4.1.1). The sensor continues measuring using the prior standard calibration.

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2.7.3.2.2 Product calibration: Assignment

After successful initial measurement a correct value must be assigned to the initially stored measurement data. This is achieved by writing the correct calibration value to register 5322.

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write access

5322 2 pH value [pH] 16 none A/S

Figure 2.7.3.2.2.1: Definition of register 5322

Command: CP6: Assignment

Modbus address: 5322 Length: 2 Type: 16

Write Parameter: Value Format: Float Value:

7.2

Figure 2.7.3.2.2.2: Example to assign a calibration value to the above performed initial measurement.

This is achieved by writing the correct pH value. From now on the sensor is measuring using the here performed product calibration. The calibration status (register 5318) is 0x14000000meaning that a correct value has been assigned

and that the product calibration is active (see figure 2.7.4.1.1).

2.7.3.2.3 Product calibration: Cancel

To cancel an active product calibration or an active initial measurement the command 0x02 is written to register 5340.

Command: CP6: Cancel

Modbus address: 5340 Length: 2 Type: 16

Write Parameter: Command Format: Hex Value:

0x02

Figure 2.7.3.2.3.1: Example to cancel an active product calibration or an initial measurement. Writing

the command 0x02 (cancel) to register 5340.

Performing this action the product calibration or any initial measurements are canceled. The values of the prior product calibration are removed from the sensor’s memory. From now on the sensor is measuring using its prior CP1 / CP2 standard calibration.

The sensor’s calibration status (register 5318) will be reading 0x00 again (see figure 2.7.4.1.1).

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2.7.3.2.4 Product calibration: Restore standard calibration

If a product calibration is active this product calibration can be temporarily switched off by writing the command 0x03 to register 5340. Performing this action the values of the product calibration remain stored in the sensor’s memory.

Command: CP6: Restore standard

Modbus address: 5340 Length: 2 Type: 16

Write Parameter: Command Format: Hex Value:

0x03

Figure 2.7.3.2.4.1: Example to restore a standard calibration from an active product calibration. Writing

command 0x03 (restore standard calibration) to register 5340.

From now on the sensor is measuring using its prior CP1 / CP2 standard calibration. The sensor’s calibration status (register 5318) will be reading “CP6 assigned”(0x10000000) meaning that a valid assignment for a product calibration is available in the sensor’s memory (see figure

2.7.4.1.1).

2.7.3.2.5 Product calibration: Restore product calibration

If a valid but inactivated product calibration is available in the sensors memory, the calibration status is reading “CP6 assigned”(corresponding to 0x10000000, see figure 2.7.4.1.1), this stored product calibration can be restored or reactivated by writing command 0x04 to register 5340.

Command: CP6: Restore product

Modbus address: 5340 Length: 2 Type: 16

Write Parameter: Command Format: Hex Value:

0x04

Figure 2.7.3.2.5.1: Example to restore an available product calibration from an active standard

calibration. Writing command 0x04 (restore product calibration) to register 5340.

From now on the sensor is measuring using its prior CP6 product calibration. The sensors calibration status (register 5318) will be reading 0x14000000 (corresponding to “CP6 assigned”and “CP6 active”, see figure 2.7.4.1.1) again.

If this command is performed without available product calibration in the sensor’s memory the sensor will respond with a Modbus exception since this command is not valid.

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2.7.4 Reading the Calibration Status

2.7.4.1 Reading the Calibration Status of CP1 and CP2

A standard calibration is not always successful. In order to analyze what has gone wrong, two different calibration status registers can be read:

 Register 5158 for CP1  Register 5190 for CP2

Note

Registers 5158 and 5190 contain the same information!

Bit # Hex value Definition 0 (LSB) 0x00000001 CP1: difference between CP1 and CP2 < pH 1.0 1 0x00000002 CP1: no matching calibration standard 2 0x00000004 CP1: actual temperature reading is too low 3 0x00000008 CP1: actual temperature reading is too high 4 0x00000010 CP1: temperature reading during calibration is not stable 5 0x00000020 CP1: offset a pH 7 is too low or slope is too low 6 0x00000040 CP1: offset a pH 7 is too high or slope is too high 7 0x00000080 CP1: pH reading during calibration is not stable 8 0x00000100 CP2: difference between CP2 and CP1 < pH 1.0 9 0x00000200 CP2: no matching calibration standard 10 0x00000400 CP2: actual temperature reading is too low 11 0x00000800 CP2: actual temperature reading is too high 12 0x00001000 CP2: temperature reading during calibration is not stable 13 0x00002000 CP2: offset a pH 7 is too low or slope is too low 14 0x00004000 CP2: offset a pH 7 is too high or slope is too high 15 0x00008000 CP2: pH reading during calibration is not stable … not available 24 0x01000000 CP6: out of calibration range 25 0x02000000 CP6: out of range 26 0x04000000 CP6: active 27 0x08000000 CP6: initial measurement 28 0x10000000 CP6: assigned

not available 30 0x40000000 CP2: incorrect measurement unit 31 0x80000000 CP1: incorrect measurement unit

Figure 2.7.4.1.1: Definition of the status for register 5158, 5190 and 5318 (see Figure 2.7.4.1.2 and

2.7.4.2.1).

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Reg5 / Reg6 Modbus

function code

Read access

Write access

5158 6 Status CP1

(see figure

2.7.4.1.1)

Physical unit of the last successful calibration CP1 (always pH)

pH value of the last successful calibration CP1

3, 4 U/A/S none

5190 6 Status CP2

(see figure

2.7.4.1.1)

Physical unit of the last successful calibration CP2 (always pH)

pH value of the last successful calibration CP2

3, 4 U/A/S none

Figure 2.7.4.1.2: Definition of register 5158 for CP1 and register 5190 for CP2.

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Command: Calibration status CP1

Modbus address: 5158 Length: 6 Type: 3

Read Parameter: Status Unit Value Format: Hex Hex Float Value:

0x00000080 0x00001000 4.01

Figure 2.7.4.1.3: Example to read the calibration status of CP1 after calibration CP1 at 0 = auto. The

status message is: “CP1 pH reading during calibration is not stable”(0x00000080). The physical unit of the last successful calibration is pH (0x00001000) and the last successful calibration has been performed at pH 4.01.

Command: Calibration status CP2

Modbus address: 5190 Length: 6 Type: 3

Read Parameter: Status Unit Value Format: Hex Hex Float Value:

0x00000080 0x00001000 7

Figure 2.7.4.1.4: Example to read the calibration status of CP2 after calibrating CP2 at 0 = auto. All bits

of CP2 are zero (0x00000080), indicating that the calibration was successful. The physical unit of the last calibration is pH (0x00001000) and the last successful calibration has been performed at pH 7.

Command: Calibration status CP2

Modbus address: 5190 Length: 6 Type: 3

Read Parameter: Status Unit Value Format: Hex Hex Float Value:

0x00000180 0x00001000 7

Figure 2.7.4.1.5: Example to read the calibration status of CP2 after attempt to calibrate CP2 at pH

4.01, which is the same as CP1. The value is 0x00000180 = 0x00000080 + 0x00000100. Shown is still 0x00000080 of CP1 and new 0x00000100 of CP2, which says: “CP2 space to CP1 < pH

1.0”.

2.7.4.2 Reading the Calibration Status of CP6 (Product Calibration)

The calibration status and the current state of the product calibration process (CP6) is read in the calibration status register for CP6 (register 5318).

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Reg5 / Reg6 Modbus

function code

Read access

Write access

5318 6 Status CP6

(see figure

2.7.4.1.1)

Physical unit of the last successful calibration CP6 (always pH)

pH value of the last successful calibration CP6

3, 4 U/A/S none

Figure 2.7.4.2.1: Definition of register 5318 for CP6. For examples, see following chapters.

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2.7.4.2.1 Product calibration: Initial measurement

Calibration status after initial measurement command under conditions outside the valid calibration range for CP6 (defined in register 5312):

Command: Calibration status CP6

Modbus address: 5318 Length: 6 Type: 3

Read Parameter: Status Unit Value Format: Hex Hex Float Value:

0x01000000 0x00001000 4.01

Figure 2.7.4.2.1.1: Example to read the calibration status of CP6 after having performed an initial

measurement at CP6 under measurement conditions outside the calibration range for CP6. The status says: “CP6: out of calibration range”(0x01000000). The last successful calibration has been performed at pH 4.01. The initial measurement in this case was not successful. The sensor is still running on its prior standard calibration.

Calibration status after successful initial measurement:

Command: Calibration status CP6

Modbus address: 5318 Length: 6 Type: 3

Read Parameter: Status Unit Value Format: Hex Hex Float Value:

0x08000000 0x00001000 4.01

Figure 2.7.4.2.1.2: Example to read the calibration status of CP6 after having performed an initial

measurement at CP6 under correct measurement conditions. The status says: “CP6: initial measurement”(0x08000000). The last successful calibration has been performed at pH 4.01. The initial measurement in this case was successful. The sensor is still running on its prior standard calibration until a valid calibration value has been assigned to this initial measurement values.

2.7.4.2.2 Product calibration: Assignment

Calibration status after invalid assignment:

Command: Calibration status CP6

Modbus address: 5318 Length: 6 Type: 3

Read Parameter: Status Unit Value Format: Hex Hex Float Value:

0x0A000000 0x00001000 4.01

Figure 2.7.4.2.2.1: Example to read the calibration status of CP6 after having performed a valid initial

measurement at CP6 and an invalid assignment. The status says: “CP6: out of range”(0x02000000) and “CP6: initial measurement” (0x08000000). The last successful calibration has been performed at pH 4.01 The initial measurement in this case is still valid and available for further assignment of a product calibration value. The here performed assignment was not successful. The sensor remains running on its prior standard calibration.

Calibration status after valid assignment:

Command: Calibration status CP6

Modbus address: 5318 Length: 6 Type: 3

Read Parameter: Status Unit Value Format: Hex Hex Float Value:

0x14000000 0x00001000 4.5

Figure 2.7.4.2.2.2: Example to read the calibration status of CP6 after having performed an initial

measurement at CP6 and a valid assignment to pH 4.5. The status says: “CP6: active”(0x04000000) and “CP6: assigned”(0x10000000). The last successful calibration corresponding to the here performed assignment has been performed at pH 4.5.

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The here performed assignment was successful. The sensor is running using a valid product calibration.

2.7.4.2.3 Product calibration: Cancel

Calibration status after cancelling an active product calibration:

Command: Calibration status CP6

Modbus address: 5318 Length: 6 Type: 3

Read Parameter: Status Unit Value Format: Hex Hex Float Value:

0x00000000 0x00001000 4.5

Figure 2.7.4.2.3.1: Example to read the calibration status of CP6 after having performed a cancel

command at CP6. The status reports no messages. The last successful calibration at CP6 has been performed at pH 4.5. The sensor is running on a valid standard calibration and no product calibration is stored.

2.7.4.2.4 Product calibration: Restore standard calibration

Calibration status after restoring a standard calibration from an active product calibration:

Command: Calibration status CP6

Modbus address: 5318 Length: 6 Type: 3

Read Parameter: Status Unit Value Format: Hex Hex Float Value:

0x10000000 0x00001000 4.5

Figure 2.7.4.2.4.1: Example to read the calibration status of CP6 after having restored the standard

calibration from an active product calibration (CP6). The status says: “CP6 assigned”(0x10000000). The last successful calibration at CP6 has been performed at pH 4.5. The sensor is running on a valid standard calibration but a valid product calibration is still available in the sensor.

2.7.4.2.5 Product calibration: Restore product calibration

Calibration status after restoring an available product calibration from an active standard calibration:

Command: Calibration status CP6

Modbus address: 5318 Length: 6 Type: 3

Read Parameter: Status Unit Value Format: Hex Hex Float Value:

0x14000000 0x00001000 4.5

Figure 2.7.4.2.5.1: Example to read the calibration status of CP6 after having restored an available

product calibration (CP6) from an active standard calibration (CP1 / CP2). The status says: “CP6: active”(0x04000000) and “CP6: assigned”(0x10000000). The last successful calibration corresponding to the here performed assignment has been performed at pH 4.5. The sensor is running on a valid product calibration again.

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2.7.5 Currently active Calibration Parameters part 1

In registers 5164 (CP1), 5196 (CP2) and 5324 (CP6) the currently active calibration parameters part 1 are stored. These registers contain the valuesfor temperature, number of calibrations and operating hour upon calibration.

Start register

Number of registers

Reg1 / Reg2 Reg3 /

Reg4

Reg5 / Reg6

Reg7 / Reg8

Modbus function code

Read access

Write access

5164 8 Unit of

temperature for CP1 (bitwise defined)

Value of temperature of CP1

Number of calibrations at CP1

Operating hour for CP1

3, 4 U/A/S none

5196 8 Unit of

temperature for CP2 (bitwise defined)

Value of temperature of CP2

Number of calibrations at CP2

Operating hour for CP2

3, 4 U/A/S none

5324 8 Unit of

temperature for CP6 (bitwise defined)

Value of temperature of CP6

Number of calibrations at CP6

Operating hour for CP6

3, 4 U/A/S none

Figure 2.7.5.1: Definition of register 5164 for CP1, 5196 for CP2 and 5324 for CP6.

Command: Calibration CP1 values

Modbus address: 5164 Length: 8 Type: 3

Read Parameter: Unit of temperature Temperature Number of cali Operating hour Format: Hex Float Decimal Float Value:

0x00000004 24.35184 6 23.78

Figure 2.7.5.2: Example to read the calibration values for CP1. The physical unit is °C (0x00000004),

the temperature is 24.35184 °C, the number of calibrations at CP1 is 6 and the operating hour is

23.78 h.

Command: Calibration CP2 values

Modbus address: 5196 Length: 8 Type: 3

Read Parameter: Unit of temperature Temperature Number of cali Operating hour Format: Hex Float Decimal Float Value:

0x00000004 24.37691 5 16.45

Figure 2.7.5.3: Example to read the calibration values for CP2. The physical unit is °C (0x00000004),

the temperature is 24.37691 °C, the number of calibrations at CP1 is 5 and the operating hour is

16.45 h.

Command: Calibration CP6 values

Modbus address: 5324 Length: 8 Type: 3

Read Parameter: Unit of temperature Temperature Number of cali Operating hour Format: Hex Float Decimal Float Value:

0x00000004 29.93368 12 379.5167

Figure 2.7.5.4: Example to read the calibration values 1 for CP6. The physical unit is °C (4), the

temperature is 29.93 (°C), the number of calibrations at CP1 is 12 and the operating hour is

379.51 (h).

2.7.6 Currently active Calibration Parameters part 2

Registers 5172 (CP1), 5204 (CP2) and 5332 (CP6) are not defined for pH ARC Sensors, as they document atmospheric pressure and salinity used for VISIFERM DO / VISIFERM DO ARC Sensors only.

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2.7.7 Currently active Calibration Parameters part 3

In register 5520, 5528 and 5560 the pH value of the used calibration standards, the electrical potential of the pH sensor and the temperature upon calibration are stored.

Start register

Number of registers

Reg1 / Reg2

Reg3 / Reg4

Reg5 / Reg6

Reg7 / Reg8

Modbus function code

Read access

Write access

5520 8 pH value of

calibration standard at CP1 [pH]

Electrical potential at CP1 [mV]

free 3, 4 A/S none

5528 8 pH value of

calibration standard at CP2 [pH]

Electrical potential at CP2 [mV]

free 3, 4 A/S none

5560 8 pH value of

product at CP6 [pH]

Electrical potential at CP6 [mV]

free 3, 4 A/S none

Figure 2.7.7.1: Definition of register 5520, 5528 and 5560.

Command: Act calibration CP1

Modbus address: 5520 Length: 8 Type: 3

Read Parameter: pH CP1 [pH] Voltage CP1 [mV] Temp CP1 [K] free Format: Float Float Float Float Value:

4.003401 179.927 297.1378 0

Figure 2.7.7.2: Example to read the actual calibration values of CP1.

Command: Act calibration CP2

Modbus address: 5528 Length: 8 Type: 3

Read Parameter: pH CP2 [pH] Voltage CP2 [mV] Temp CP2 [K] free Format: Float Float Float Float Value:

7.006804 3.099747 296.6901 0

Figure 2.7.7.3: Example to read the actual calibration values of CP2.

Command: Act calibration CP6

Modbus address: 5560 Length: 8 Type: 3

Read Parameter: pH CP6 [pH] Voltage CP6 [mV] Temp CP6 [K] free Format: Float Float Float Float Value:

7.1 5.10469 298.3302 0

Figure 2.7.7.4: Example to read the actual calibration values of CP6.

2.7.8 Currently active Calibration Parameters part 4

For standard calibration (CP1 / CP2) register 5448 documents offset at pH7 and slope:

Start register

Number of registers

Reg1 / Reg2 (Float)

Reg3 / Reg4 (Float)

Reg5 / Reg6 (Float)

Modbus function code

Read access

Write access

5448 6 Offset at

pH 7 [mV]

Slope (25 °C) [mV/pH]

Reference temperature [K]

3, 4 U/A/S none

Figure 2.7.8.1: Definition of register 5448.

Command: Calculated cali values

Modbus address: 5448 Length: 6 Type: 3

Read Parameter: Offset at pH 7

[mV]

Slope [mV/pH]

Ref temp

[K] Format: Float Float Float Value:

3.607782 -59.47631 298.15

Figure 2.7.8.2: Example to read register 5448: offset at pH 7 is 3.6 mV; slope is -59.5 mV/pH; reference

temperature is 298.15 K (=25°C)

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2.7.9 Special Commands for Calibration with VISICAL

The VISICAL calibration device allows calibration of pH ARC Sensors at CP1 or CP2. The pH ARC Sensor’s associated calibration parameters for CP1 and CP2 are those predefined and stored in corresponding registers of the sensor. Register 5164 defines the pH value for CP1 and register 5196 defines the pH value for CP2, which are only valid for use with VISICAL. The same calibration limits for the pH value are used as for standard calibration at CP1 and CP2 (register 5152 and 5184 respectively).

Attention:

 It is not possible to perform a product calibration using VISICAL.  Physical unit is fixed to pH by definition.

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write

access 5180 2 pH value at CP1 (default: pH 4.00) 3, 4, 16 U/A/S S 5212 2 pH value at CP2 (default: pH 7.00) 3, 4, 16 U/A/S S

Figure 2.7.9.1: Definition of register 5180 for CP1 and 5212 for CP2.

Command: VISICAL CP1

Modbus address: 5180 Length: 2 Type: 3

Read Parameter: Value [pH] Format: Float Value:

4.00

Figure 2.7.9.2: Example to read the pH value valid for CP1. It is 4.00. Accordingly, the next time when a

calibration is started using VISICAL at LOW, a calibration with manual selection is performed, using the calibration standard at pH 4. The operator has to make sure that - within the selected set of calibration standards - a standard at pH 4 is selected for manual selection.

Command: VISICAL CP2

Modbus address: 5212 Length: 2 Type: 16

Write Parameter: Value [pH] Format: Float Value:

7.00

Figure 2.7.9.3: Example to set the pH value valid for CP2.

Command: VISICAL CP2

Modbus address: 5212 Length: 2 Type: 3

Read Parameter: Value [pH] Format: Float Value:

7.00

Figure 2.7.9.4: Example to read the pH value valid for CP2. It is 7.00. Accordingly, the next time when a

calibration is started using VISICAL at HIGH, a calibration with manual selection is performed, using the calibration standard at pH 7. The operator has to make sure that - within the selected set of calibration standards - a standard at pH 7 is selected for manual selection.

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2.7.10 Calibration Standards

2.7.10.1 Available Sets of Calibration Standards

pH ARC Sensors can store and operate six different sets of calibration standards each having max 12 calibration standards. Before calibration the operator has to select one defined set to operate with. Default setting is the HAMILTON set of calibration standards. The operator can change the selection of sets at any time, without compromising prior calibration data at CP1 / CP2.

In register 9472 the available sets of calibration standards are defined.

Start register

Number of registers

Reg1 / Reg2 (Bit, see Figure 2.7.10.1.2)

Modbus function code

Read access

Write access

9472 2 Available calibration standard sets 3, 4 U/A/S none

Figure 2.7.10.1.1: Definition of register 9472.

Bit # Hex value Description Definition

0 (LSB) 0x00000001 Set 1 HAMILTON

1 0x00000002 Set 2 MERCK TITRISOL 2 0x00000004 Set 3 DIN 19267 3 0x00000008 Set 4 NIST Standard 4 0x00000010 Set 5 METTLER-TOLEDO 5 0x00000020 Set 6 RADIOMETER

Figure 2.7.10.1.2: Definition of available sets of calibration standards.

Command: Available cali sets

Modbus address: 9472 Length: 2 Type: 3

Read Parameter: Calibration sets Format: Hex Value:

0x0000003F

Figure 2.7.10.1.3: Example to read the available calibration sets: Set 1 (0x00000001) + set 2

(0x00000002) + set 3 (0x00000004) + set 4 (0x00000008) + set 5 (0x00000010) + set 6 (0x00000020), in total 0x0000003F.

In register 9474 the selected set of calibration standards is defined.

Start register

Number of registers

Reg1 / Reg2 (Bit, see Figure 2.7.10.1.2)

Modbus function code

Read access

Write access

9474 2 Selected set of calibration standard 3, 4 U/A/S S

Figure 2.7.10.1.4: Definition of register 9474. Only one bit can be set.

Command: Selected set of cal stand.

Modbus address: 9474 Length: 2 Type: 3

Read Parameter: Calibration set Format: Hex Value:

0x00000001

Figure 2.7.10.1.5: Example to read the selected set of calibration standards. Set 1 (HAMILTON)

(0x00000001) is active.

Command: Select set of cal stand.

Modbus address: 9474 Length: 2 Type: 16

Write Parameter: Calibration set Format: Hex Value:

0x04

Figure 2.7.10.1.6: Example to set the calibration standard set to DIN 19267 (0x04).

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2.7.10.2 Definitions for Individual Sets of Calibration Standards

Once the operator has selected a set of calibration standards (register 9474) the register 9504 and following give all information on the selected set of calibration standards.

Start register

Number of registers

Reg1 … Reg8 (16 ASCII characters)

Modbus function code

Read access

Write

access 9504 8 Manufacturer of the selected set 3, 4 U/A/S none 9512 8 Info 1 of the selected set 3, 4 U/A/S none 9520 8 Info 2 of the selected set 3, 4 U/A/S none

Figure 2.7.10.2.1: Definition of registers 9504 to 9520.

Command: manufacturer of set

Modbus address: 9504 Length: 8 Type: 3

Read Parameter: Text Format: Character Value:

HAMILTON

Figure 2.7.10.2.2: Example to read the description (in this case, the set 0x01 is selected) Within one set of calibration standards, a maximum of 12 calibration standardsare available. In the

following registers, the details of each calibration standard is given:

Start register Description 9536 Nominal value and tolerance of calibration standard 1 9552 Nominal value and tolerance of calibration standard 2 9568 Nominal value and tolerance of calibration standard 3 9584 Nominal value and tolerance of calibration standard 4 9600 Nominal value and tolerance of calibration standard 5 9616 Nominal value and tolerance of calibration standard 6 9632 Nominal value and tolerance of calibration standard 7 9648 Nominal value and tolerance of calibration standard 8 9664 Nominal value and tolerance of calibration standard 9 9680 Nominal value and tolerance of calibration standard 10 9696 Nominal value and tolerance of calibration standard 11 9712 Nominal value and tolerance of calibration standard 12

Figure 2.7.10.2.3: Definition for the register range from 9536 until 9720.

Start register

Number of registers

Reg1 / Reg2 (Float)

Reg3 / Reg4 (Float)

Reg5 / Reg6 (Float)

Reg7 / Reg8 (Float)

Modbus function code

Read access

Write access

9536, 9552,

…

8 Calibr.

standard nominal value [pH]

Tolerance of nominal value (±) [pH]

Nominal electrical potential [mV]

Tolerance of electrical potential (±) [mV]

3, 4 U/A/S none

Figure 2.7.10.2.4: Definition for registers 9536 until 9720.

Command: Read standard 4

Modbus address: 9584 Length: 8 Type: 3

Read Parameter: Nominal value

[pH]

Tolerance (±) [pH]

Nominal electrical potential [mV]

Tolerance of electrical potential

(±) [mV] Format: Float Float Float Float Value:

4.01 0.02 180 80

Figure 2.7.10.2.5: Example to read the values for the calibration standard 4.

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 the available calibration standards for manual selection of the pH value  the available calibration standards for automatic recognition of the pH value

Start register

Number of registers

Reg1 / Reg2 (Bit, see figure 2.7.10.2.8)

Modbus function code

Read access

Write access

9528 2 Availability of the 12 cal. standards 3, 4 U/A/S none

Figure 2.7.10.2.6: Definition of register 9528

Command: Available standards

Modbus address: 9528 Length: 2 Type: 3

Read Parameter: Standard fields Format: Hex Value:

0x0FFF0FFF

Figure 2.7.10.2.7: Example to read the information of register 9528. For the definition of the bits, see

Figure 2.7.10.2.8. The value 0x0FFF0FFF says that (for the selected set of calibration standards):

 all 12 calibration standards are available for manual calibration  all 12 calibration standardsare available for automatic recognition.

Bit Hex code Index of Calibration

Standard within the selected set

Calibration type

0 (LSB) 0x00000001 1 manual selection 1 0x00000002 2 manual selection 2 0x00000004 3 manual selection 3 0x00000008 4 manual selection 4 0x00000010 5 manual selection 5 0x00000020 6 manual selection 6 0x00000040 7 manual selection 7 0x00000080 8 manual selection 8 0x00000100 9 manual selection 9 0x00000200 10 manual selection 10 0x00000400 11 manual selection 11 0x00000800 12 manual selection 12-15 not available 16 0x00010000 1 automatic recognition 17 0x00020000 2 automatic recognition 18 0x00040000 3 automatic recognition 19 0x00080000 4 automatic recognition 20 0x00100000 5 automatic recognition 21 0x00200000 6 automatic recognition 22 0x00400000 7 automatic recognition 23 0x00800000 8 automatic recognition 24 0x01000000 9 automatic recognition 25 0x02000000 10 automatic recognition 26 0x04000000 11 automatic recognition 27 0x08000000 12 automatic recognition 28-31 not available

Figure 2.7.10.2.8: Availability / Selection for the 12 calibration standards within one given set.

Bit 0-11 define availability of standards 1-12 for manual calibration. Bit 16-27 define availability of standards 1-12 for automatic recognition Register 9528: the corresponding calibration standard is available if bit is set Register 9530: the corresponding calibration standard is selected if bit is set

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By means of register 9530, the specialist can define for each available calibration standard if the specific standard is available.

Start register

Number of registers

Reg1 / Reg2 (Bit, see figure 2.7.10.2.8)

Modbus function code

Read access

Write access

9530 2 Selected standard fields 3, 4 U/A/S S

Figure 2.7.10.2.9: Selected calibration standards within one given set.

Command: Selected standard fields

Modbus address: 9530 Length: 2 Type: 3

Read Parameter: Standard fields Format: Hex Value:

0x02480FFF

Figure 2.7.10.2.10: Example to read the selected calibration standards. The value 0x02480FFF says

that:

 all 12 calibration standards are selected for manual selection  only calibration standards 3, 7 and 10 are selected for automatic recognition

Command: Selected standard fields

Modbus address: 9530 Length: 2 Type: 16

Write Parameter: Standard fields Format: Hex Value:

0x05540FFF

Figure 2.7.10.2.11: Example to set the standard fields to 12 calibration standards for manual calibration

and calibration standard 3 (0x00040000), 5 (0x00100000), 7 (0x00400000), 9 (0x01000000) and 11 (0x04000000) for automatic recognition.

Attention:

The standards selected for automatic recognition must exhibit a difference in pH of at least 2 pH units.

Figure 2.7.10.2.12: Illustration from the ARC Sensor Configurator software tool for registers 9528 and

9530. For this example, the HAMILTON set of calibration standard is selected. On the left half of the figure, the availability of the calibration standards 1-12 is shown, as defined

in register 9528. In the left column, the availiability for manual calibration is shown (all standards). In the right column, the availability for automatic recognition is given (all standards as well).

On the right half of the figure, the individual selection defined by the specialist is shown as read

from register 9530. In the left column, the selection for manual selection is shown (all standards). In the right column the selection for automatic recognition is given (calibration standards 4, 7 and 10).

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Manufacturer Availability for manual selection (left) and

automatic recognition (right)

HAMILTON

MERCK TITRISOL

DIN 19267

NIST STANDARD

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Manufacturer Availability for manual selection (left) and

automatic recognition (right)

METTLER TOLEDO

RADIOMETER

Figure 2.7.10.2.13: Default definitions in register 9528 for all 6 sets of calibration standards available in

pH ARC Sensors.

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2.8 Sensor Status

2.8.1 Temperature Ranges

In registers 4608, 4612 and 4616 three different temperature ranges are defined:

 Operation –in this range the sensor will work properly (current output, Modbus

communication), except the measurement, which is stopped until the temperature is back in the measurement range. In this case the last value of measurement will be frozen and sent to analog interfaces.

 Measurement –in this range the sensor is able to measure.  Calibration –in this range the sensor can be calibrated.

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Modbus

function code

Read access

Write access

4608 4 Operating

temperature min [°C]

Operating temperature max [°C]

3, 4 U/A/S none

4612 4 Measurement

temperature min [°C]

Measurement temperature max [°C]

3, 4 U/A/S none

4616 4 Calibration

temperature min [°C]

Calibration temperature max [°C]

3, 4 U/A/S none

Figure 2.8.1.1: Definition of register 4608, 4612 and 4616.

Command: Operating T range

Modbus address: 4608 Length: 4 Type: 3

Read

Parameter: Operating T min

[°C]

Operating T max

[°C] Format: Float Float Value:

-20 130

Figure 2.8.1.2: Example to read the operating temperature values min and max.

Command: Measurement T range

Modbus address: 4612 Length: 4 Type: 3

Read

Parameter: Measurement T

min [°C]

Measurement T

max [°C] Format: Float Float Value:

-20 130

Figure 2.8.1.3: Example to read the measurement temperature values min and max.

Command: Calibration T range

Modbus address: 4616 Length: 4 Type: 3

Read

Parameter: Calibration T min

[°C]

Calibration T max

[°C] Format: Float Float Value:

5 50

Figure 2.8.1.4: Example to read the calibration temperaturevalues min and max.

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2.8.2 Operating Hours and Counters

In register 4676 are given:

 total operating hours  operating hours above max measurement temperature (see chapter 2.8.1)  the operating hours above max operating temperature (see chapter 2.8.1)

In register 4682 are stored:

 number of power ups  number of watchdog resets  number of writing cycles to the sensor’s flash memory

In register 4688 are given:

 number of sterilizations in place (SIP) (see chapter 2.8.5)  number of cleanings in place (CIP) (see chapter 2.8.5)

Start register

Number of registers

Reg1 / Reg2 Reg3 / Reg4 Reg3 / Reg4 Modbus

function code

Read access

Write access

4676 6 Operating

hours [h]

Operating hours above max measurement temperature [h]

Operating hours above max operating temperature [h]

3, 4 U/A/S none

4682 6 Number of

Power ups

Number of Watchdog resets

Number of Writing cycles to flash memory

3, 4 U/A/S none

4688 4 Number of

SIP cycles

Number of CIP cycles

- 3, 4 U/A/S none

Figure 2.8.2.1: Definition of register 4676, 4682 and 4688.

Command: Operating hours

Modbus address: 4676 Length: 6 Type: 3

Read

Parameter: Operating hours [h] Operating hours

above max measurement temperature [h]

Operating hours above max operating temperature

[h] Format: Float Float Float Value:

168.3667 0 0

Figure 2.8.2.2: Example to read the total operating hours, the operating hours above the max

measurement temperature and the operating hours above the max operating temperature.

Command: Power & watchdog

Modbus address: 4682 Length: 6 Type: 3

Read

Parameter: Number of Power

ups

Number of Watchdog resets

Number of Writing

cycles to flash

memory Format: Decimal Decimal Decimal Value:

34 1 16

Figure 2.8.2.3: Example to read the number of power ups, the number of watchdog resets and the

number of writing cycles to flash memory.

Command: SIP & CIP

Modbus address: 4688 Length: 4 Type: 3

Read Parameter: SIP cycles CIP cycles Format: Decimal Decimal Value:

0 0

Figure 2.8.2.4: Example to read the number of SIP cycles and the number of CIP cycles. For the

definition of SIP and CIP cycles see chapter 2.8.5.

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2.8.3 Warnings

A “Warning”is a notification message which still allows further functioning of the system. This message alerts the operator of a possible problem that could lead to uncertain results.

2.8.3.1 Currently Active Warnings

The currently active warnings are stored in register 4736.

Start register

Number of registers

Reg1 / Reg2

Reg3 / Reg4

Reg5 / Reg6

Reg7 / Reg8

Modbus function code

Read access

Write access

4736 8 Active

warning measurement (bitwise defined)

Active warning calibration (bitwise defined)

Active warning interface (bitwise defined)

Active warning hardware (bitwise defined)

3, 4 U/A/S none

Figure 2.8.3.1.1: Definition of register 4736 (see chapter 2.8.3.3)

Command: Active warning

Modbus address: 4736 Length: 8 Type: 3

Read Parameter: W Measurement W Calibration W Interface W Hardware Format: Hex Hex Hex Hex Value:

0x00 0x00 0x00 0x00

Figure 2.8.3.1.2: Example to read the currently active warnings.

2.8.3.2 History of Warnings

The history of warnings is not implemented in pH ARC Sensors.

2.8.3.3 Definition of Warnings

Bit # Hex Description

not available

Figure 2.8.3.3.1: Definition of warnings “measurement”. None is defined.

Bit # Hex Description 0 (LSB) 0x0001 PMC1 (pH) calibration recommended 1 0x0002 PMC1 (pH) last calibration not successful

Figure 2.8.3.3.2: Definition of warnings “calibration”.

Bit # Hex Description

not available

Figure 2.8.3.3.3: Definition of warnings “interface”. None is defined.

Bit # Hex Description

not available

Figure 2.8.3.3.4: Definition of warnings “hardware”. None is defined.

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2.8.4 Errors

An “Error”message indicates a serious problem of the sensor which does not allow further proper functioning of the sensor. This problem must be solved.

2.8.4.1 Currently Active Errors

The currently active errors are stored in register 4800.

Start register

Number of registers

Reg1 / Reg2

Reg3 / Reg4

Reg5 / Reg6

Reg7 / Reg8

Modbus function code

Read access

Write access

4800 8 Active error

measurement (bitwise defined)

Active error calibration (bitwise defined)

Active error interface (bitwise defined)

Active error hardware (bitwise defined)

3, 4 U/A/S none

Figure 2.8.4.1.1: Definition of register 4800 (see chapter 2.8.4.3)

Command: Active errors

Modbus address: 4800 Length: 8 Type: 3

Read Parameter: E Measurement E Calibration E Interface E Hardware Format: Hex Hex Hex Hex Value:

0x00 0x00 0x00 0x00

Figure 2.8.4.1.2: Example to read the currently active errors.

2.8.4.2 History of Errors

The history of errors is not implemented in pH ARC Sensors.

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2.8.4.3 Definition of Errors

Bit # Hex Description

not available 5 0x0000020 Glass resistance too high 6 0x0000040 Glass resistance too low 7 0x0000080 Reference electrode resistance too high 8 0x0000100 Reference electrode resistance too low

not available 15 0x0008000 Auxiliary electrode electrical potential too high 16 0x0010000 Auxiliary electrode electrical potential too low 17 0x0020000 Auxiliary electrode resistance too high 18 0x0040000 Auxiliary electrode resistance too low

not available 25 0x2000000 Temperature sensor defective

Figure 2.8.4.3.1: Definition of errors “measurement”.

Bit # Hex Description 1 0x0000002 Sensor failure (Quality value < 15%)

Figure 2.8.4.3.2: Definition of errors “calibration”.

Bit # Hex Description

not available

Figure 2.8.4.3.3: Definition of errors “interface”. None is defined.

Bit # Hex Description

not available 24 0x1000000 Internal communication error (betweenfront-end and user-end)

Figure 2.8.4.3.4: Definition of errors “hardware”.

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2.8.5 Reading Definition of SIP and CIP

pH ARC Sensor are counting special cleaning events such as sterilizations or cleaning cycles by means of tracking typical temperature profiles (see chapter 2.8.2).

Register 4988 defines a typical temperature profile for SIP (sterilizationin place) and register 4996 for CIP (cleaning in place). For the explanation the following values are given:

CIP temperature min: 80 °C CIP temperature max: 100 °C CIP time min: 30 minutes SIP temperature min: 120 °C SIP temperature max: 130 °C SIP time min: 30 minutes

CIP and SIP

100

120

140

08:00

08:15

08:30

08:45

09:00

09:15

09:30

09:45

10:00

10:15

10:30

10:45

11:00

11:15

11:30

11:45

12:00

12:15

12:30

12:45

13:00

13:15

13:30

13:45

14:00

14:15

14:30

14:45

15:00

15:15

15:30

15:45

16:00

16:15

16:30

16:45

17:00

Time

Temperature [°C]

T CIP T SIP CIP min CIP max SIP min SIP max

no SIP 1) SIP ok 3)

CIP ok 2)

no CIP 4) no CIP 4)

Figure 2.8.5.1: Definition of CIP and SIP cycles.

1) no SIP-cycle counted, because time too short <30 minutes.

2) CIP-cycle counted, because time >30 minutes and in CIP temperature range.

3) SIP-cycle counted, because time >30 minutes and in SIP temperature range.

4) no CIP-cycle counted, because of reaching the SIP-min limit.

Start register

Number of registers

Reg1 / Reg2

Reg3 / Reg4

Reg5 / Reg6

Reg7 / Reg8

Modbus function code

Read access

Write access

4988 8 SIP

Temperature min [°C]

SIP Temperature max [°C]

SIP Process time min [min]

Empty 3, 4 U/A/S S

4996 8 CIP

Temperature min [°C]

CIP Tempera-

-ture max [°C]

CIP Process time min [min]

Empty 3, 4 U/A/S S

Figure 2.8.5.2: Definition of register 4988 and 4996.

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Command: SIP definition

Modbus address: 4988 Length: 8 Type: 16

Write Parameter: T min [°C] T max [°C] Time min [min] Empty Format: Float Float Float Float Value:

120 130 30 0

Figure 2.8.5.3: Example to write the SIP definitions.

Command: SIP definition

Modbus address: 4988 Length: 8 Type: 3

Read Parameter: T min [°C] T max [°C] Time min [min] Empty Format: Float Float Float Float Value:

120 130 30 0

Figure 2.8.5.4: Example to read the SIP definitions.

Command: CIP definition

Modbus address: 4996 Length: 8 Type: 16

Write Parameter: T min [°C] T max [°C] Time min [min] Empty Format: Float Float Float Float Value:

80 100 30 0

Figure 2.8.5.5: Example to write the CIP definitions.

Command: CIP definition

Modbus address: 4996 Length: 8 Type: 3

Read Parameter: T min [°C] T max [°C] Time min [min] Empty Format: Float Float Float Float Value:

80 100 30 0

Figure 2.8.5.6: Example to read the CIP definitions.

2.8.6 Reading the Sensor’s Quality Indicator

In register 4872 the sensor’s quality indicator (0-100%) is given.

Start register

Number of registers

Reg1 / Reg2 (Float)

Modbus function code

Read access

Write access

4872 2 Quality [%] 3, 4 U/A/S none

Figure 2.8.6.1: Definition of register 4872.

Command: Quality indicator

Modbus address: 4872 Length: 2 Type: 3

Read Parameter: Quality [%] Format: Float Value:

100

Figure 2.8.6.2: Example to read the sensor’s quality indicator. The sensor’s quality indicator is influenced by:

 Offset a pH 7  Slope  Errors

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2.9 Sensor Identification and Information

2.9.1 General Information

General information about the sensor is available as shown in the figure below.

Start register

Number of registers

Reg1 … Reg8 (16 ASCII characters)

Example of content Modbus

function code

Read access

Write access

1024 8 Userend FW Date 2010-04-28 3, 4 U/A/S none 1032 8 Userend FW EPHUM011 3, 4 U/A/S none 1040 8 Userend BL Date 2009-09-18 3, 4 U/A/S none 1048 8 Userend BL BL0UX012 3, 4 U/A/S none 1056 8 Userend P/N 242822/01 3, 4 U/A/S none 1064 8 Userend S/N not available 3, 4 U/A/S none 1072 8 Userend (space holder) not available 3, 4 U/A/S none 1080 8 Userend (space holder) not available 3, 4 U/A/S none 1088 8 Frontend FW Date 2009-09-16 3, 4 U/A/S none 1096 8 Frontend FW EPHFI010 3, 4 U/A/S none 1104 8 Frontend BL Date not available 3, 4 U/A/S none 1112 8 Frontend BL not available 3, 4 U/A/S none 1120 8 Frontend P/N 242828/00 3, 4 U/A/S none 1128 8 Frontend S/N not available 3, 4 U/A/S none 1136 8 Frontend (space holder) not available 3, 4 U/A/S none 1144 8 Frontend (space holder) not available 3, 4 U/A/S none

Figure 2.9.1.1: Definition of registers containing read-only sensor information.

Command: Userend Firmware

Modbus address: 1032 Length: 8 Type: 3

Read Parameter: Text Format: Character Value:

EPHUM011

Figure 2.9.1.2: Example to read register 1032.

2.9.2 Sensor Identification

Start register

Number of registers

Reg1 … Reg8 (16 ASCII characters)

Example of content Modbus

function code

Read access

Write access

1280 8 Part number 242111/01 3, 4 U/A/S none 1288 8 Sensor name Polilyte Plus 3, 4 U/A/S none 1296 8 Work order number 3214567 3, 4 U/A/S none 1304 8 Work order date 2010-04-30 3, 4 U/A/S none 1312 8 Serial number 0001001 3, 4 U/A/S none 1320 8 Manufacturer part 1 HAMILTON Bonaduz 3, 4 U/A/S none 1328 8 Manufacturer part 2 AG Switzerland 3, 4 U/A/S none 1336 8 Sensor type ARC e. pH Sensor 3, 4 U/A/S none 1344 8 Power supply 007..030V 0150mW 3, 4 U/A/S none 1352 8 Pressure range 0 ... 6 bar 3, 4 U/A/S none 1360 8 Sensor ID 242111-0001001 3, 4 U/A/S none 1368 8 a-length 120 3, 4 U/A/S none 1376 8 (space holder) not available 3, 4 U/A/S none 1384 8 Electrical connection VP 8.0 3, 4 U/A/S none 1392 8 Process connection PG 13.5 3, 4 U/A/S none 1400 8 Sensing material H-Glass 3, 4 U/A/S none

Figure 2.9.2.1: Definition of registers containing sensor identification.

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Command: Serial number

Modbus address: 1312 Length: 8 Type: 3

Read Parameter: Text Format: Character Value:

0001001

Figure 2.9.2.2: Example to read register 1312.

2.9.3 Free User Memory Space

These registers can be used to store any customer specific information in the sensor. There are different registers which can be read by everybody, but only specific operators can write them.

Start register

Number of registers

Reg1 … Reg8 (16 ASCII characters)

Example of content Modbus

function code

Read access

Write access

1536 8 Free user space U/A/S *FREE_USERSPACE* 3, 4, 16 U/A/S U/A/S 1544 8 Free user space U/A/S *FREE_USERSPACE* 3, 4, 16 U/A/S U/A/S 1552 8 Free user space U/A/S *FREE_USERSPACE* 3, 4, 16 U/A/S U/A/S 1560 8 Free user space U/A/S *FREE_USERSPACE* 3, 4, 16 U/A/S U/A/S 1568 8 Free user space A/S *FREE_USERSPACE* 3, 4, 16 U/A/S A/S 1576 8 Free user space A/S *FREE_USERSPACE* 3, 4, 16 U/A/S A/S 1584 8 Free user space A/S *FREE_USERSPACE* 3, 4, 16 U/A/S A/S 1592 8 Free user space A/S *FREE_USERSPACE* 3, 4, 16 U/A/S A/S 1600 8 Measuring point 242111-0001001 3, 4, 16 U/A/S S 1608 8 Free user space S *FREE_USERSPACE* 3, 4, 16 U/A/S S 1616 8 Free user space S *FREE_USERSPACE* 3, 4, 16 U/A/S S 1624 8 Free user space S *FREE_USERSPACE* 3, 4, 16 U/A/S S 1632 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1640 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1648 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1656 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1664 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1672 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1680 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1688 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1696 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1704 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1712 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1720 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1728 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1736 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1744 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none 1752 8 Free user space others *FREE_USERSPACE* 3, 4 U/A/S none

Figure 2.9.3.1: Definition of registers containing user information.

An important register is 1600, as it is the description of the measuring point. The information of this register is displayed on the ARC View Handheld in order to identify individual sensors.

Attention: The Free User Memory Space is located in a memory which allows in total max 10’000 write operations.

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Command: Info user

Modbus address: 1568 Length: 8 Type: 16

Write Parameter: Text Format: Character Value:

Hello World

Figure 2.9.3.2: Example to write 16 ASCII characters to register 1568 with operator A or S.

Command: Info user

Modbus address: 1568 Length: 8 Type: 3

Read Parameter: Text Format: Character Value:

Hello World

Figure 2.9.3.3: Example to read the register 1568 (written in figure 2.9.1.6).

2.10 System Commands

2.10.1 Recall Sensor’s Factory Settings

Using register 8192 you can recall the sensor manufacturer values (interfaces, calibration data and passwords), except the SIP and CIP data which remain unchanged. By sending the recall value “732255”, all configuration values will be set to default.

Start register

Number of registers

Reg1 / Reg2 Modbus

function code

Read access

Write access

8192 2 Recall by value 732255 16 none S

Figure 2.10.1.1: Definition of register 8192.

Command: Recall

Modbus address: 8192 Length: 2 Type: 16

Write Parameter: Recall Format: Decimal Value:

732255

Figure 2.10.1.2: Example to write the restore command.

3 Abbreviations

AO Analog Output Interface CP Calibration Point ECS Electrochemical Sensor Interface PMC Primary Measurement Channel SMC Secondary Measurement Channel

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HAMILTON Bonaduz AG Via Crusch 8 CH-7402 Bonaduz Switzerland

Tel. +41 81 660 60 60 Fax +41 81 660 60 70

contact@hamilton.ch 05 May 2010 www.hamiltoncompany.com Manual P/N: 624300/01

Hamilton EPHUM011 Programmer's Manual

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