Hamilton Electronics EPHUM011 - Manual (Page 30)

pH ARC Sensors Modbus RTU Programmer ’ s Manual (EPHUM011)
624300/01 page 30 / 67
2.6.3 PA12: Moving Average R
pH ARC Sensors allow to have a separate moving average on secondary measurement values:
 Glass resistance
 Reference resistance
The moving average can be applied on 1 to 16 3-s measurement values. The default value is 4.
Especially if high resistances are measured, it is recommended to choose a higher moving average.
2.6.3.1 Description of PA12 (Moving Average R)
In register 3456, a plain text ASCII description of PA12 is given.
Start
register Number of
registers Reg1 … Reg8
16 ASCII characters
Modbus
function code Read
access Write
access
3456 8 Description of PA12 3, 4 U/A/S none
Figure 2.6.3.1.1: Definition of register 3456.
Command: Moving average text Modbus address: 3456 Length: 8 Type: 3 Read
Parameter: Text
Format: Character
Value:
Moving average R
Figure 2.6.3.1.2: Example to read the description for “ Moving average R “ .
2.6.3.2 Selecting the Physical Unit and Writing the Value for PA12
In register 3464, the available physical units for PA12 are defined.
Start
register Number of
registers Reg1 / Reg2
(bitwise defined) Modbus
function code Read
access Write
access
3464 2 Available physical units for PA12 3, 4 U/A/S none
Figure 2.6.3.2.1: Definition of register 3368.
Command: Moving average av. units Modbus address: 3464 Length: 2 Type: 3
Read
Parameter: Units
Format: Hex
Value:
0x01
Figure 2.6.3.2.2: Example to read the available physical units for PA12. The only one available here is
“ none ”(0x01). For the definition of the physical units see chapter 2.5.1.
Start
register Number of
registers Reg1 / Reg2
(bitwise defined) Reg3 / Reg4 Modbus
function code Read
access Write
access
3466 4 Select physical unit
for PA12 Value for PA12
(1-16, default: 4) 16 none S
Figure 2.6.3.2.3: Definition of register 3466. Only one bit for the physical unit can be set. PA12 can be
set to the values 1-16.