CDCN91-Controller

Supported Applications

The Omega CDCN-91 Series is a dual-channel conductivity/resistivity controller designed for monitoring and controlling process fluids. The series supports applications requiring precise measurement of conductivity, resistivity, Total Dissolved Solids (TDS), and temperature. It features programmable setpoints with adjustable hysteresis to manage alarm and control functions.

Documented application contexts include:

• Water treatment processes
• General process fluid monitoring and control
• Simultaneous display of two independent channels for comparative analysis (e.g., Percent Reject, Difference, or Ratio)

Operating Conditions & Performance

The CDCN-91 Series operates within specific environmental limits to ensure measurement integrity. The ambient operating temperature range is -10 to 55 °C (14 to 131 °F), with a storage temperature of -15 to 80 °C (5 to 176 °F). Humidity tolerance is rated at 0 to 95%, non-condensing.

Performance specifications for the series include:

• Conductivity Range: 0.055 µS/cm to 400,000 µS/cm (displayed as 0.055 µS/cm to 400.00 mS/cm)
• Resistivity Range: 10 kΩ/cm to 18.26 MΩ/cm
• TDS Range: 0.001 to 99,999 ppm or ppb (display limit)
• Temperature Measurement: -25 to 120 °C (-13 to 248 °F) using PT1000 sensors
• Accuracy: ±2% of reading for Conductivity/Resistivity; ±0.5°C for Temperature (0 to 100 °C); ±0.03 mA @ 25°C, 24 VDC for current outputs
• Update Rate: Approximately 1.5 seconds per update cycle

The enclosure is rated NEMA 4X (IP65) on the front and back when equipped with the optional rear cover kit.

Configuration Options

The CDCN-91 Series offers configurable power, output signaling, and mounting options to accommodate diverse installation requirements. The series supports both AC and DC power configurations via distinct model numbers (CDCN-91 for DC; CDCN-91AC for AC/DC).

Power Supply Options

• CDCN-91: 11 to 24 VDC ±10%, regulated, 0.5 A max
• CDCN-91AC: 100 to 240 VAC ±10%, 50-60 Hz, 20 VA (also supports DC input)

Output Signals & Control

• Analog Outputs: Up to three fully scalable and isolated 4 to 20 mA outputs. Max loop impedance is 150 Ω @ 12 V, 450 Ω @ 18 V, or 750 Ω @ 24 V.
• Digital Outputs: Up to four programmable SPDT relays (5 A @ 250 VAC, 5 A @ 30 VDC).
• Open Collector: Two optically isolated outputs available; 50 mA sink or source with a maximum pull-up voltage of 30 VDC.

Sensor & Connection Options

• Sensors: Compatible with Omega CDCE-90 Series Standard and Certified Conductivity/Resistivity Electrodes (cell constants from 0.01 to 20.0).
• Cabling: Three-conductor shielded cable for sensor extensions up to 30 m (100 ft). Liquid tight connector kits (FPM-5000-LTCK) are available.

Housing & Mounting

• Enclosure: PBT case with polyurethane-coated polycarbonate window and sealed 4-key silicone rubber keypad. Includes optional NEMA 4X (IP65) rear cover kit.
• Mounting: Standard panel mounting; optional heavy-duty wall mount bracket (CDCN-91-WMB) or surface mounting bracket (FPM-5000-MB).

Key Product Differences

The primary distinction within the CDCN-91 Series is the power supply configuration, which defines the model number:

• CDCN-91: Designed for DC power applications (11 to 24 VDC).
• CDCN-91AC: Supports both AC and DC power inputs.

The series utilizes a dual-channel architecture allowing simultaneous monitoring of Channel 1 and Channel 2. Display modes vary based on channel configuration, showing either two conductivity values (C1/C2), one conductivity value with its corresponding temperature, or calculated ratios/differences between channels. The device includes output simulation capabilities for system testing.