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pH ARC Sensors Modbus RTU Programmer’s Manual (EPHUM011)
624300/01 page 51 / 67
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).