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

2.7.3.2.2Product 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

Number of

Reg1 / Reg2

 

 

Modbus

Read

Write

register

registers

 

 

 

 

function code

access

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 0x14000000 meaning that a correct value has been assigned and that the product calibration is active (see figure 2.7.4.1.1).

2.7.3.2.3Product 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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Hamilton Electronics EPHUM011 manual Product calibration Assignment, Product calibration Cancel