Varec 8200, Installation And Operation Manual, Page: 9 / 38

Current Output Transmitter
Varec, Inc. 1
1 Introduction
This manual is designed to assist the user in the installation, operation, calibration, and
maintenance of the Varec 8200 Current Output Transmitter (8200 COT).
1.1 Getting Acquainted with the Varec Current Output Transmitter
The 8200 COT is an electromechanical device that is mechanically coupled to the sprocket drive
sheave of a Varec 2500 Automatic Tank Gauge (2500 ATG) gaugehead or other liquid level
indicating gaugehead (see Figure 1-1).
Figure 1-1: Varec 8200 Current Output Transmitter
As the liquid level gauge sprocket drive sheave rotates with liquid level changes, the motion
turns the transmitter drive shaft. The drive shaft is coupled to a worm gear that drives the shaft
of a potentiometer. Rotation causes the current in the instrumentation output loop of the
transmitter to vary. The current loop variations are carried through a conductor pair (two wires)
to a central receiver or indicator to provide the signal to an instrument that is calibrated to
remotely display the level of the fluid in the tank as it is shown on the gaugehead at the tank.
An increase in current normally indicates a rising liquid level. An outage (reverse) reading
current output option is available.
A typical installation of the 8200 COT consists of directly mounting it onto a 2500 ATG
gaugehead. It may also be mounted onto a gaugehead of other manufacturers.
The transmitter requires nominal electrical input of 15 – 48 volts of regulated direct current
(VDC), or 120 VAC/220 – 240 VAC. Current sensing analog instruments that measure current
ranges of either 4-20 mA or 10-50 mA signal, are required in the current instrumentation loop.
Transmitter housing
Encoder mechanism
and optional limit switches
DC voltage supply
transmitter board
part number
08-06886-2
AC voltage supply
transmitter board
part number
08-06886-1
Junction box
included with certain
options only
3/4 inch NPT
O-Ring
Cover
OR
Shaft coupling/
encoder mounting
hardware
3/4 inch NPT