Specifications/Operating Instruction
Model CT-1000
General Description
The model CT-1000 (encapsulated miniature transmitter) is a 2-wire, 4-20mA blind conductivity
transmitter featuring encapsulated construction, high performance and compact size.
Connect a conductivity cell of k=0.1 or 1.0 to it to then transform the output to a 4-20mA current
proportional to the conductivity level. This output may be transmitter over 2 wires to a control
location. The same 2 wires provide power to the transmitter. Any DC power supply from
12 to 36V DC may be used. There are two adjustments on the transmitter to standardize the
conductivity output marked as “SPAN” and “ZERO”. The output can be monitored with a looppowered meter, a loop resistor or a multimeter during the standardization process.
SPECIFICATIONS
Input: ………………………………………. 0-100,000 uS (see range
label on transmitter)
Output: ………………………………………4-20mA
Power Supply: ……………………………….12-36V DC
Load Resistor: ……………………………….0-750
Linearity: …………………………………… +
Operating Temperature Range: ………………-25 to 70
Ω
at 24V DC
0.02uS
°
C
Reverse Polarity Protection: …………………Internal diode
Dimensions: …………………………………1.5” x 2.0” x 1.0”
Maximum sensor to transmitter distance ….. DO NOT EXCEED 25ft.
1
Installation
1. Two 6-32 mounting holes 9” centers are provided. The transmitter can be mounted in a
head, weather-proof box, or DIN rail.
2. The output wires are isolated from ground; connections are made at the terminal strip
observing polarity to the terminals marked + , -out. These wires are to be connected to a
DC power supply through a load resistor. The wires can be as long as necessary.
Connect the ground terminal to earth ground.
3. The loop resistor can be either in the positive or negative power supply lead. The value
of the loop resistor depends on the voltage required at the monitoring location. Calculate
the required power supply voltage from the following equation:
minimum V
A convenient value for the loop resistor (R
voltage would be:
minimum V
The maximum supply voltage is 36V DC.
4. Connect sensor to transmitter by matching wire color to designated color on terminal
block (i.e. electrode’s red wire to terminal block “RED”, …)
5. Turn the unit on end with the conductivity cell in the air and adjust the “ZERO” to an
output current of 4.00mA
6. Put the conductivity cell in a conductivity solution that exceeds the highest expected
value and adjust “SLOPE” to an output current of 20.00mA
7. SPECIAL NOTE: The transmitter is supplied with a 10K resistor in place of where the
temperature compensation can be connected. Leave the resistor in place if your
electrode does not have temperature compensation (2-wires only). Remove the resistor
if your electrode has 3 wires.
power supply
= 12 + (0.02 x R
loop
power supply
= 12 + (0.02 x 250) = 17V DC
)
loop
) might be 250Ω and so the minimum power
2
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