pH ARC SensorsModbus RTU Programmer’s Manual (EPHUM011)
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2.5.5 Secondary Measurement Channels 1-16
pH ARC Sensorsdo allow access to secondary measurement values (16 in total). The accesst o the
individual SMCdepends on the operator level. The available SMC are defined in register 2048
according tot heselected operator level and the sensor type (see chapter 2.5.1).
2.5.5.1 Descriptionof SMC
The registersdefi nedhere give a plain text ASCII description of each available SMC.
Start
register Number of
registers Reg1…Reg8
16 ASCII characters Modbus
function code Read
access Write
access
Address 8 Description ofeach SMC 3, 4 U/A/S none
Figure 2.5.5.1.1:Definition of registers at Address
Description Address Plain Text
(16 ASCII) Description
SMC1 2464 R glass Resistanceof the pH glass
SMC2 2496 R reference Resistanceof the referenceelectrode
SMC3 2528 R auxiliary Resistance of the auxiliary electrode
SMC4 2560 E pH vs. ref Electrical potential between glass and reference electrode
SMC5 2592 E SG vs. ref Electrical potential between solution ground and reference
electrode
SMC6 2624 E aux vs. ref Electricalpotential between auxiliary electrode and reference
electrode
SMC7 2656 E reference Electrical potential betweenreference electrode and electrical
ground
SMC8 2688 pH act Current pH value (3-seconds-reading)
SMC9 2720 T act Current T value (3-seconds-reading)
Figure 2.5.5.1.2: Full list of starting register addressesf or the plain text ASCII description of each SMC
Example:
Command: SMC 1 text Modbusaddress: 2464 Length: 8Type: 3Read
Parameter: Text
Format: Character
Value: R glass
Figure 2.5.5.1.3:Example to read the description of SMC1 at address 2464. It is “R glass”.