VersaTRAK RTU User M anual
Page 16 of 31
Last Revised: 05/23/02
SIXNET
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Box 767
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Clifton Park, NY 12065 USA
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+1 (518) 877-5173
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FAX +1 (518) 877-8346
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VersaTRAK
Analog Inputs
The VersaTRAK RTU has eight analog input channels that accept loop powered or self
powered 4-20 mA signals.
Analog Input
Wiring
One screw terminal (31) is provided for the return wires from all input channels. One terminal
is provided for each analog input signal. If any of your 4-20 mA transmitters require loop
power, connect 24 VDC into the loop as shown below. (The 24 VDC may come from an
external DC power source or from the VT-PS-024-01N power supply.) Connect all self-
powered 4-20 mA input field devices as shown in the diagram below.
Analog Input
Group Isolation
The eight VersaTRAK analog input channels are isolated (as a group) from the VersaTRAK
circuitry and expansion I/O modules.
Analog Input
Scaling
These 4-20 mA inputs are reported as unscaled values from 0 to 32767. Refer to the SIXNET
I/O Tool Kit online help system for more information.
Open Loop
Detection Feature
The SIXNET I/O Tool Kit configuration program provides a selection that allows inputs
below 4 mA to be reported as zero, or be reported as negative values to detect loop failure.
Replaceable
Current Shunts
VersaTRAK RTUs have a replaceable 100 ohm precision current shunt for each analog input,
should a faulty field device or wiring error causes the original shunt to overheat.
Note:
Shunt replacement requires VersaTRAK disassembly. Consult
SIXNET
for details
should shunt replacement become necessary.
VersaTRAK On-board Analog Input Connections
