CN7400-Series

Supported Applications

The Omega CN7400 Series consists of FM-approved and UL Approved limit controllers designed for mounting in enclosed panels. These universal process limit controls support a wide range of input types, including thermocouples (K, J, T, E, N, R, S, B, L/J DIN, C), RTDs (Pt100 0.00385/0.00392, Pt1000, Nickel 120 Ω), and DC voltage or current signals. The series is engineered for applications requiring digital displays of the process variable (PV) and set value (SV), with configurable relay outputs to manage limit conditions.

Operating Conditions & Performance

The CN7400 Series operates within an ambient temperature range of -10 to 55°C (14 to 131°F). Measurement ranges vary by input type, spanning from -350 to 750°F (-212 to 398°C) for T Thermocouples up to 0 to 4208°F (-17 to 2320°C) for C Thermocouples. RTD inputs cover ranges such as -200 to 875°C (-328 to 1607°F). Scalable process input types (current and voltage) support a range of -1999 to 9999 with adjustable decimal point positions.

Accuracy is specified at ±0.25% of span, ±1 least significant digit. The display resolution defaults to 0.1°; however, if the temperature exceeds 999.9° or drops below -199.9°, the display returns to whole-degree resolution.

Physical and Electrical Specifications

• Housing Dimensions: Panel cut-out of 45 mm² (1.77 in²); bezel size is 48 mm² (1.9 in²) with a panel depth requirement of 133 mm (5.24").
• Weight: 227 g (8 oz).
• Power Supply: Standard models accept 100 to 240 Vac, nominal ±10%, 50 to 400 Hz; single phase. DC power options include 132 to 240 Vdc, nominal ±20%. A low voltage option (LV) supports 12 - 24 Vdc/Vac.
• Enclosure Rating: IP66 and UL type 4 when installed with proper spacing; closer than 19mm (0.75in) between instruments invalidates this rating.

Configuration Options

The series offers configurable output configurations to meet specific control logic needs. Standard outputs include SPST relays rated at 3 A @ 240 Vac (Resistive) or 1.5 A @ 240 Vac (Inductive). Outputs can be configured as Normally Open (Form "A") or Normally Closed (Form "B"). The controller allows Form "A" and Form "B" relays to be logically linked to emulate a Form "C" output.

Available Configurations

• Model CN7430: Single output with NO relay.
• Model CN7434: Dual output featuring both NO and NC relays.
• Analog Retransmission (-PV1): Adds a 0 to 20 mA isolated retransmission output for the process variable.
• Noise Suppression (CNQUENCHARC): Field-installable RC snubber accessory with 2 leads, rated for 110 to 230 Vac.

Key Product Differences

The primary distinction within the CN7400 Series lies in the output relay configuration. The CN7430 model provides a single Normally Open (NO) relay, while the CN7434 includes both NO and NC relays for dual-output applications. Both models support remote reset capability.

Input flexibility is inherent to all units in the series, accepting universal inputs across 10 thermocouple types, 4 RTD types, DC voltage, or DC current without requiring separate hardware variants for each sensor type; selection is managed via programming. The -PV1 option suffix differentiates models that include analog retransmission from those with relay-only outputs.