200 | Hamilton Electronics EPHUM011 manual

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

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				Standard Calibration function
						Standard Calibration function
						Product Calibration function
		150
	[mV]	100
	[mV]	50
	potential	50	CP1		CP6
			CP1		CP6
		0
		5	6	7	8	9	10
	Electrical	5	6	7	8	9	10
		-50
		-100
		-100
		-150				CP2
						CP2
		-200
					pH

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

624300/01

page 40 / 67

Image 40

Hamilton Electronics EPHUM011 manual 200

Contents

PH ARC Sensors Important Notice Configuration of the Serial RS485 Interface Configuration of the Analog InterfacesConfiguration of the Measurement Sensor Identification and Information Visiferm do Modbus RTU Programmer’s Manualp/n 624179/01 IntroductionEPHUM011 Operator levels and Passwords Reading / Setting Operator LevelGeneral 0x03 Changing Passwords for Operator Level 0x300x0C 18111978 0x0B 18111978 Configuration of the serial RS485 Interface Device AddressReading and Writing the Device Address Reading the Device Address Limits Reading and Writing the Baud Rate Baud RateReading the Baud Rate Limits Configuration of the Analog Interfaces Available Analog InterfacesAvailable Analog Interface Modes 0x07 Selection of an Analog Interface Mode Description of the Analog Interfaces 1MA interface #1 MA interface #2 0x21 Configuration of the 4-20 mA Interface0x01 PH ARC Sensors Modbus RTU Programmer’s Manual EPHUM011 0x001000 Reading the Selected Physical Unit for Analog InterfaceDefining the Measurement Values for 4, 12 and 20 mA Output PH ARC sensor 4-20mA inte rface linear Defining a Constant Current Output for Testing 0x010001 Reading the Internally Measured Output Current 99186 99742 Measurement Definition of Measurement Channels and Physical Units Special Primary Measurement Channel 1 pH Description of PMC1Selecting the Physical Unit for PMC1 0x201000 0x1000 02503 0x00 Reading the measurement value of PMC10x200000 175.9922 0x00 954.6541 Primary Measurement Channel 6 Temperature Description of PMC6Selecting the Physical Unit for PMC6 0x06 Input of an Externally Measured Temperature Definition of the Measurement Status for PMC1 / PMC6Reading the measurement value of PMC6 0x04 24.35834 0x00 130 Secondary Measurement Channels Description of SMC Reading the measurement value of SMC 0x8000 247.56 Configuration of the Measurement Available Parameters 2 PA9 Moving Average Effect of Moving Average n=1 vs n=16 Description of PA9 Moving Average Selecting the Physical Unit and Writing the Value for PA9 Reading all Values for PA9 Description of PA12 Moving Average R 3 PA12 Moving Average RSelecting the Physical Unit and Writing the Value for PA12 Reading all Values for PA12 Calibration Available Calibration Points Definitions of Calibration Points Calibration Points 1 and 2 Standard CalibrationCP1 CP2 Calibration Point 6 Product Calibration CP6 Calibration Procedure Calibration at CP1 and CP2 Standard Calibration PH ARC Sensors Modbus RTU Programmer’s Manual EPHUM011 Choose one of the calibration points CP1 or CP2 0x00000000 0x00001000 100 Calibration at CP6 Product Calibration 200 Definition of the commands for product calibration Product calibration Initial measurement Product calibration Cancel Product calibration Assignment Product calibration Restore standard calibration Product calibration Restore product calibration Reading the Calibration Status Reading the Calibration Status of CP1 and CP2 0x00000180 0x00001000 0x00000080 0x00001000Reading the Calibration Status of CP6 Product Calibration 0x01000000 0x00001000 0x08000000 0x000010000x0A000000 0x00001000 0x14000000 0x00001000 0x10000000 0x00001000 Currently active Calibration Parameters part 0x00000004 24.35184 23.780x00000004 24.37691 16.45 0x00000004 29.93368 379.5167 003401 179.927 297.1378 006804 099747 296.690110469 298.3302 607782 59.47631 298.15 Special Commands for Calibration with Visical Calibration Standards Available Sets of Calibration StandardsLSB 0x00000001 Set 0x0000003F Definitions for Individual Sets of Calibration Standards 180 0x0FFF0FFF 0x02480FFF 0x05540FFF DIN Nist Standard Mettler Toledo Radiometer Temperature Ranges Sensor Status Operating Hours and Counters 168.3667 History of Warnings Currently Active WarningsDefinition of Warnings Currently Active Errors ErrorsHistory of Errors Definition of Errors SIP Reading Definition of SIP and CIPCIP Reading the Sensor’s Quality Indicator 120 130 Sensor Identification and Information General InformationSensor Identification EPHFI010 0001001 Free User Memory SpaceFreeuserspace System Commands Recall Sensor’s Factory SettingsHello World 732255 PH ARC Sensors Modbus RTU Programmer’s Manual EPHUM011