wtw Turb 2000 Series, Operating Manual

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Additional features and options Turb 2000 Series
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7.2 RS-485 outputs
The Turb 2000 series has the capability to operate in three different RS-485 modes for all models. A
simple communication mode is included. Another operating mode is the Modbus communications. All
modes will automatically configure and do not require any changes or selections.
7.2.1 Simple communication
The Turb 2000 series can provide basic communications over simple programs such as the Hilgraeve
HyperTerminal that is included with most Microsoft Windows packages. The user could also use Visual
Basic or other programs. The default communication parameters are 8 bits, no parity and 1 stop bit.
These can be changed in the Extended CONFIG menus (section 6.14 RS-485
P
ARAMETERS
).
The master computer will send out:
•
Byte #1 the attention character “:” in ASCII or 3A Hex
•
Byte #2 the address of the Turb 2000 instrument being queried
•
Byte #3 & 4 CR LF or 0D 0A in hex
The Turb 2000 will respond with:
•
The same attention character “:” in ASCII or 3A Hex
•
The address of the Turb 2000 instrument
•
The Reading
•
The Unit (NTU)
A sample communication would look like this:
(Master computer requesting a report from address #1) : 1 CRLF
(Turb 2000 set to address #1 Response) :001 0.0249 NTU
7.2.2 Modbus communication
Modbus protocol communication is operational on all models. The Modbus information is covered in the
appendix of this manual.
7.3 Flow alarm
The flow switch for the Turb 2000 series is a factory-installed option. This option indicates a “Low Flow”
condition by switching both relays to the fail state and setting the 4-20 mA signal to 2 mA. There is also
a screen indication of the low flow condition and a modbus register is set.
7.4 Flow controller
The flow controller limits the flow, in high-pressure systems, to safe flow limits of less than 1
liter/minute.