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WT-VO Voltage Out

Water Height Probe

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The WT-VO is a Voltage Output Water Height Probe with voltage outputs for both water height and water temperature. Water height probes are available for:

¼    meter 250mm WT-VO 250
½    meter 500mm WT-VO 500
1    meter 1000mm WT-VO 1000
1½ meter 1500mm WT-VO 1500
2    meter 2000mm WT-VO 2000

The WT-VO has the following basic features:

RS232 serial port for testing and setup
Externally Powered
Water height voltage output
Water temperature Voltage output
Voltage outputs can be scaled to give from 500mV to 2.425 V output at full scale
Water Height output is temperature compensated to reduce the temperature effect on the output.

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Water Height:
Sensor Type
304 Stainless Steel Outer
316 Stainless Steel available for special orders
Working Temperature 0º C to +50º C
Accuracy ± 1% Full Scale
Resolution ± 1mV
Temperature Coefficient ± 0.2mm/º C
Water Temperature:
Sensor Type Thermister
Sensor Position Bottom of Water Height Probe
Working Temperature 0º C to +50º C
Linear accuracy over range ± 0.3º C
Repeatability ± 0.1º C
Long term stability ± 0.1º C
Voltage Output:
Connecter 3 way screw terminal block
   1 Water Height Voltage Output
   2 Water Temperature Output
   3 Comon Ground
   see below
Voltage Span Can be scaled   from 500mV to 2.425V full scale
Minimum span 0 to 500mV
Maximum span 0 to 2.425V
RS232 Interface:
Connecter 9pinD Female
Protocol 19200baud 8N1
Connecter 2 way screw terminal block
Voltage    1 Positive supply 5 to 14V
   2 Negative Supply Comon Ground
   see below
Required Current 3mA Typical
5mA Max
Logger Length Diameter Weight
WT-VO 250      
WT-VO 500 820mm 20mm 588gm
WT-VO 1000 1320mm 20mm 975gm
WT-VO 1500 1820mm 20mm 1363gm
WT-VO 2000 2320mm 20mm 1750gm

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RS232 Communications with the WT-VO

The WT-VO can be read and setup using ASCII Commands sent to the RS232 Port. This can be done using any RS232 Communication software such as Windows HyperTerminal. There is also a  WT-VO user interface in the Omnilog software. see below  

Baud Rate 19200
Parity None
Data Bits 8
Stop Bits 1



Expected Bytes of Response
R Read Data 115
L Set Zero Point (Low) 25
H Set Top Point (High) 26
COK Calibrate 114
O&&&& Set Output Span 41
S00250 Set probe hight to 250mm 28
S00500 Set probe hight to 500mm 28
S01000 Set probe hight to 1000mm 28
S01500 Set probe hight to 1500mm 28
S02000 Set probe hight to 2000mm 28
V Read Version Number 23
F Set DtoA to Full for 1min 63
K#### Set Cal Ref to #### 28
Z Diagnostic Read 300

:   #### is a 4 digit ASCII String representing the Cal Ref Voltage in millivolts. It is greater than or equal to 2300 and less than or equal to 2500.

:   &&&& is a 4 digit ASCII String representing the Output Span Voltage in millivolts. It is greater than or equal to 0500 and less than or equal to 2425

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Using Omnilog to Read and Setup a WT-VO

The Omnilog software includes a user interface for the WT-VO voltage output water hight probe. This is accessed from Tools...General Toolbox...WT-VO Calibration

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The following operations are available:

Select the Comm Port that the WT-VO is connected to.

To read data from the probe:

Click the "Read WT-VO" Button
Information from the Probe will be displayed in the output window

To change the output span:

The system outputs 0 volts at 0mm water hight
The maximum voltage that is output at maximum water height can be set between 500mV and 2425mV (2.425Volts) This is the probes span
To set the span, enter the required span in the box labeled "Out Span"
This should be entered in mV like 500, 1000, 2000, 2048
Click the "Set Output Span" button
The Output Span is now set

To calibrate the probe:

Click the Read WT-VO Button to check that communications is working
Put the probe in water up to the Zero mark and click the Zero Point Button
Put the probe in water up to the High mark and click the High Point Button
Click the Calibrate WT-VO Button
The probe is now calibrated.

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