OJ Electronics VTH-6202 Instructions page 2

Holding register
0x03: Read
0x06: Write Single
0x10: Write Multiple
Register Function
1 Minimum PPM
2 Maximum PPM
Input register
0x04: Read
Register Function
1 Component name
2 Application ID
3 Software version
4 Hardware version
5 VOC level
6 VOC status
7 VOC percentage
TROUBLESHOOTING
Symptom
No communication between
controller and VTH-6202
Incorrect VOC measurement
2
Range Resolution
0-65535
0-65535
Range Resolution
22
4
100 -
100 -
450-32767
Bit position Status
0x0001 ALARM
0x0002 ERROR
0x0004 IDLE
0x0008 OUT OF RANGE
0x0100 INTERNAL
0-100%
Cause
Broken or poor connection
Wrong Modbus address
Wrong Modbus communication
parameters
Defective receiving unit
Defective VTH-6202
Self-calibration not completed
Measuring hole in VTH-6202 is
dirty or the free, unobstructed
passage of air through the hole
is impeded in some other way
Incorrect positioning of VTH-
6202 within the duct
Defective VTH-6202
Unit
1 PPM 0% of VOC value
1 PPM 100% of VOC value
Unit
- - Fixed value
- - Fixed value
0.01 - VOC sensor version
0.01 - VOC sensor version
1 PPM Available 15 minutes after power has been connected.
No answer from sensor element.
Sensor element returns error.
VOC value not yet available.
VOC value outside measuring range.
Only used for testing purposes.
0.01 % Percentage in relation to min. and max. PPM. Available 15
minutes after power has been connected.
Action
Check that cable and connectors are connected properly.
Check that any joints and extension cable are connected properly.
Set the correct Modbus address and the correct Modbus communication parameters
in the receiving unit. VTH-6202 has Modbus address 110 Dec.
Set the correct Modbus address and the correct Modbus communication parameters
in the receiving unit. Communication parameters for VTH-6202 are 38.4 kBaud, 1 start
bit, 8 data bits, 2 stop bits and no parity.
Replace receiving unit.
Replace VTH-6202.
During start-up the sensor element can take up to seven days for self-calibration. This
also applies when there is a power outage. Wait until self-calibration is completed.
Remove dirt or other material preventing free, unobstructed passage of air through the
measuring hole.
Check the physical position of VTH-6202 within the duct. Wherever possible, the VTH-
6202 measuring hole should be positioned close to the centre of the duct. The sensor
should be installed in such a way that the air flow in the duct can pass unhindered
through the measuring hole at the end of the sensor, which should be aligned parallel
to the air flow.
Replace VTH-6202.
© 2017 OJ Electronics A/S
Remarks
Remarks