Hamilton Electronics EPHUM011 - Manual (Page 28)

pH ARC Sensors Modbus RTU Programmer ’ s Manual (EPHUM011)
624300/01 page 28 / 67
2.6.2.1 Description of PA9 (Moving Average)
In register 3360, a plain text ASCII description of PA9 is given.
Start
register Number of
registers Reg1 … Reg8
16 ASCII characters
Modbus
function code Read
access Write
access
3360 8 Description of PA9 3, 4 U/A/S none
Figure 2.6.2.1.1: Definition of register 3360.
Command: Moving average text Modbus address: 3360 Length: 8 Type: 3 Read
Parameter: Text
Format: Character
Value: Moving average
Figure 2.6.2.1.2: Example to read the description for “ Moving average “ .
2.6.2.2 Selecting the Physical Unit and Writing the Value for PA9
In register 3368, the available physical units for PA9 are defined.
Start
register Number of
registers Reg1 / Reg2
(bitwise defined) Modbus
function code Read
access Write
access
3368 2 Available physical units for PA9 3, 4 U/A/S none
Figure 2.6.2.2.1: Definition of register 3368.
Command: Moving average av. units Modbus address: 3368 Length: 2 Type: 3 Read
Parameter: Units
Format: Hex
Value: 0x01
Figure 2.6.2.2.2: Example to read the available physical units for PA9. 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
3370 4 Select physical unit
for PA9 Value for PA9
(1-16, default: 2) 16 none S
Figure 2.6.2.2.3: Definition of register 3370. Only one bit for the physical unit can be set. PA9 can be
set to the value 1-16. A value of 1 does not influence the response time of the sensor, a value of
16 increases the response time of the sensor to 48 s.
By writing to register 3370 the active physical unit for PA9 can be selected by choosing one of the
physical units that are defined in register 3368. The value of the parameter can be set as well.
Command: Moving average Modbus address: 3370 Length: 4 Type: 16 Write
Parameter: Unit Value
Format: Hex Decimal
Value: 0x01 12
Figure 2.6.2.2.4: Example to set the physical unit of PA9 to “ none ”(0x01) and the value of the moving
average to 12.