Hamilton Electronics EPHUM011 - Manual (Page 10)

pH ARC Sensors Modbus RTU Programmer ’ s Manual (EPHUM011)
624300/01 page 10 / 67
2.4.3 Description of the Analog Interfaces 1 and 2
Register 4352 / 4480 contain the descriptions of AO1 / AO2 as plain text ASCII:
Start
register Number of
registers Reg1 … Reg8
16 ASCII characters
Modbus
function code Read
access Write
access
4352 8 Description of AO1 3, 4 U/A/S none
4480 8 Description of AO2 3, 4 U/A/S none
Figure 2.4.2.1: Definition of register 4352 and 4480
Command: Current interface text Modbus address: 4352 Length: 8 Type: 3 Read
Parameter: Text
Format: Character
Value:
mA interface #1
Figure 2.4.2.2: Example to read the description of AO1. The text is “ mA interface #1” . Accordingly,
AO1 is physically configured as a 4-20 mA current output.
Command: Current interface text Modbus address: 4480 Length: 8 Type: 3
Read
Parameter: Text
Format: Character
Value: mA interface #2
Figure 2.4.2.3: Example to read the description of AO2. The text is “ mA interface #2” . Accordingly,
AO2 is physically configured as a 4-20 mA current output.
Attention:
 pH ARC Sensors do not have an ECS (in contrast to VISIFERM DO)!
 Data structure: register address offset between AO1 and AO2 is always 128.
2.4.4 Selection of an Analog Interface Mode
The analog interface mode of AO1 / AO2 is selected by programming the analog interface mode in
register 4360 / 4488.
Start
register Number of
registers Reg1 / Reg2 Modbus
function code Read
access Write
access
4360 2 Active analog interface mode for AO1 3, 4, 16 U/A/S S
4488 2 Active analog interface mode for AO2 3, 4, 16 U/A/S S
Figure 2.4.4.1: Definition of register 4360 / 4488. Only one bit can be set.
Command: Active interface mode Modbus address: 4360 Length: 2 Type: 16 Write
Parameter: Mode
Format: Hex
Value: 0x02
Figure 2.4.4.2: Example to set the analog interface mode of AO1 to 0x02 (4-20 mA linear output).