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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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Specification:

Water Height:

Sensor Type

Capacitive

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

Supply:

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

Size

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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WT-VO Output Box.jpg (27193 bytes)

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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

Protocol:
	Baud Rate	19200
	Parity	None
	Data Bits	8
	Stop Bits	1

Command	Function	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
Note1: #### 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.
Note2: &&&& 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

WT-VO_cal_screen.jpg (56796 bytes)

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.