Hamilton Electronics EPHUM011 - Manual (Page 42)

pH ARC Sensors Modbus RTU Programmer ’ s Manual (EPHUM011)
624300/01 page 42 / 67
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 0x14000000 meaning that a correct value has been assigned
and that the product calibration is active (see figure 2.7.4.1.1).
2.7.3.2.3 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).