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

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

Number of

Reg1 / Reg2

Modbus

Read

Write

register

registers

 

function code

access

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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Hamilton Electronics EPHUM011 manual Special Commands for Calibration with Visical