Eutech Instruments 1000 series 1/4 DIN conductivity and resistivity controllers have an advanced set-up mode to easily customize features. Their 0 to 2000 second selectable time delay and adjustable set point hysteresis bands mean you can tailor control relay action to meet your needs.

Each unit is selectable for isolated 0-20 or 4-20 mA transmitter/recorder output; 110 or 220 VAC; normally open or closed relays; and manual or automatic temperature compensation. The compact 1/4 DIN size fits into standard panel cutouts. The IP54 rated front panel keypad is weather resistant. Includes mounting hardware.

• A menu-driven program that simplifies set-up
• Large dual display LCD shows con- ductivity (resistivity) and temperature along with clear multiple annunciators
• Two set point, two SPDT relay operation for lo/lo, lo/hi, hi/lo or hi/hi control
• 0 to 2000 second time delay adjustment on all relays— minimizes false alarms
• Separate alarm relay alerts you to set points exceeded for a specific length of time or a failed temperature sensor
• Separately adjustable high and low set point hysteresis bands prevent rapid contact switching if your mea- sured value is fluctuating near the set point
• Adjustable temperature coefficient from 0.00 to 10.00% per °C lets you input your solution’s true temperature correction for higher accuracy
• Choice of 0.01, 0.1, 1.0 or 10.0 cell constants for accurate readings in any solution
• 0-20/4-20 mA transmitter/recorder output for remote monitoring and hard copy recording
• Protection against electromagnetic interference—galvanically isolated output
• Push button keypad gives you fast access to one-point calibration, switchable manual or automatic temperature compensation, and call up to view set points
• Two level password protection— first level allows quick access to calibration; second level lets you change set up parameters
• LED indicators signal control activities to monitor controller status from a distance
• Nonvolatile memory maintains setup even when power fails

Typical Measurement and Control System 
A typical measurement system consists of:

• power source
• the OAKTON 1000-series controller
• a conductivity (or resistivity) cell with or without built-in temperature sensor (Pt 100 or 1000)
• installation hardware for cell
• an appropriate measurement cable
• a final control element such as a pump or valve
• a recorder (optional)
• a visual and/or audible alarm (optional)

Unit dimensions
The field-tested control panel housing is 3.78" x 3.78" (96 x 96 mm). 
The front panel meets protection class IP 54.
Back panel
The back panel consists of two different connectors: the 17-way PCB edge connector and the 5-way screw terminal connector.
Electrical Connections
CAUTION: Electrical shock hazard! Make sure to remove AC power to the controller before wiring input and output connections, and before opening the controller housing.

1. VAC live wire
2. VAC neutral wire
3. VAC protective ground wire
   NOTE: Power is selectable for 110 or 220 VAC via an internal jumper.
   Factory setting is indicated on the label on top of the controller.
4. Low set relay resting position
5. Low set relay common 
6. Low set relay working position
7. High set relay resting position
8. High set relay common 
9. High set relay working position
10. Alarm relay resting position
    IMPORTANT: The alarm relay functions as an “Active Low” device; e.g.
    switches OFF under alarm condition. Therefore the alarm display device should
    be connected to the 'NC' contacts of the relay.
11. Alarm relay common 
12. Alarm relay working position
13. Hold function switch terminal 1
14. Hold function switch  terminal 2
15. No connection
16. 0/4 - 20 mA for – current connection
17. 0/4 - 20 mA for + current connection

Cell/temperature sensor connections
18. Pt100/Pt1000 lead 1 terminal
19. Pt100/Pt1000 sense lead terminal
20. Pt100/Pt1000 lead 2 terminal
NOTE: If using a two-wire RTD, short terminal 19 to terminal 18.
NOTE: Pt100/Pt1000 is selectable via an internal jumper setting. Factory default
is Pt100.
the RTD type. 
21. Cell lead 1
22. Cell lead 2

HOLD function
The HOLD function lets you force the relays to their resting position by applying a contact closure across terminals 13 and 14.
When the HOLD function is activated, the HOLD indicator will appear in the upper left corner of the display.

Typical applications:
Float or level switch: Connect to a float switch in your reagent feed tank to shut down pumps or tanks when out of reagent.
Flow switch: Connect to a flow switch to shut down pumps or valves when the process stream is shut down.
Dual conductivity control: Use for dosing two chemicals in stepwise addition.