OM7-Srs-Modular-Sig-Cond

Supported Applications

The Omega OM7 Series consists of modular, isolated signal conditioning products designed for data acquisition and process control systems. These single-channel plug-in modules accept analog signals from field sensors—including thermocouples, RTDs, potentiometers, voltage sources, and current loops—and filter, isolate, amplify, linearize, or convert them to high-level analog outputs suitable for system integration.

Input types supported across the series include:

• Voltage Inputs: Isolated millivolt (mV) and volt (V) signals ranging from ±10 mV to ±10 V, including unipolar and bipolar configurations.
• Current Inputs: Process current inputs of 4 to 20 mA or 0 to 20 mA.
• Temperature Sensors: Linearized RTD inputs (100Ω Pt with alpha 0.00385, and 120Ω Ni) and thermocouple inputs (Types J, K, T, E, R, S, B, N).
• Potentiometer Inputs: Resistance ranges from 0 to 10KΩ.
• Transmitter Interface: Isolated 2-wire transmitter inputs with loop power supply (4 to 20 mA).

The system provides true channel-to-channel isolation and is configured for use in industrial environments requiring signal buffering, filtering, or conversion before transmission to data acquisition hardware.

Operating Conditions & Performance

OM7 modules operate within an ambient temperature range of -40°C to +85°C (-40°F to 185°F) and a storage temperature range of -40°C to +85°C. Humidity tolerance is rated at up to 90% non-condensing (24 hr). The modules are housed in durable plastic cases with overall dimensions of approximately 54 x 42 x 14 mm (2.13" x 1.705" x 0.605").

Performance specifications vary by module type:

• Accuracy: Factory-calibrated accuracy is typically ±0.1% of span maximum for most voltage, current, and thermocouple modules. RTD modules (OM7-34) range from ±0.15% to ±0.2%, while linearized thermocouple modules (OM7-47) offer typical accuracies between 0.08% and 0.29% of span depending on type and range.
• Nonlinearity: Maximum nonlinearity is specified at ±0.02% of span for standard input modules; RTD and linearized thermocouple modules have specific values listed in their respective tables (e.g., OM7-34-N ranges from ±0.012% to ±0.14%).
• Response Time: Response times vary by module: 1 msec for OM7-21 and OM7-22; 5 msec for OM7-35; 10 msec for OM7-32/OM7-33; 150 msec for OM7-30, OM7-31, OM7-37, and OM7-47; and 250 msec for OM7-34.
• Isolation & Protection: Modules provide 1500 V rms continuous common mode voltage isolation. Input protection is rated at 120 V rms continuous, with output short-to-ground protection on applicable modules.

Cold Junction Compensation (CJC) for thermocouple modules utilizes an external thermistor mounted under the backplane terminal blocks; CJC accuracy is ±1.0°C maximum within ambient temperatures of 5 to 45°C.

Configuration Options

The OM7 Series offers extensive configurability through a wide range of input/output modules, backplanes, and accessories designed for flexible system assembly.

Input & Output Modules

• Voltage Input: Models include OM7-21 (±10 V), OM7-30/OM7-40 (millivolt ranges 0 to ±1V, bipolar/unipolar), and OM7-31/OM7-41 (volt ranges up to ±10 V).
• Current Input: Models include OM7-32 for process current inputs of 4 to 20 mA or 0 to 20 mA.
• RTD Input: Linearized modules (OM7-34) support 100Ω Pt (-100°C to +600°C, -50°C to +350°C) and 120Ω Ni (0°C to +300°C).
• Thermocouple Input: Non-linearized modules (OM7-37) support Types J, K, T, E, R, S, B with ranges up to -100°C to +1800°C. Linearized thermocouple modules (OM7-47) add Type N and provide linearization for specific spans.
• Potentiometer Input: OM7-36 supports resistance inputs from 0 to 1KΩ up to 0 to 10KΩ.
• 2-Wire Transmitter: OM7-35 provides isolated loop power (approx. +24 V) for 4 to 20 mA transmitters with output options of 1 to 5 V or 2 to 10 V.
• Voltage Output: Unity-gain module OM7-22 accepts ±10 V and outputs ±10 V; other modules provide selectable voltage outputs (e.g., 1 to 5 V, 0 to 10 V).
• Current Output: OM7-39 converts input voltages (1 to 5 V or 0 to 10 V) to current outputs of 4 to 20 mA or 0 to 20 mA.

Housing & Mounting

• Backplanes: Available in 1, 2, 4, 8, and 16 channel configurations. Options include standard backpanels (e.g., OM7-BP-01-C) and DIN-rail versions (e.g., OM7-BP-01-C-DIN).
• Mounting: Modules feature a common pinout allowing mix-and-match installation on a single backplane. Hot-swappable design permits removal/insertion with power applied.

Power & Connectivity

• Power Supply: Nominal 24 Vdc supply; acceptable range is typically 14 to 35 Vdc (specific modules like OM7-21/OM7-22 require 19 to 29 Vdc).
• Connectors: Field wiring connects via three screw terminals per channel on the backplane. System interface uses a 25-pin D-type male connector.

Key Product Differences

The OM7 Series distinguishes between input modules that perform signal conditioning (filtering, linearization) and output modules designed for buffering or conversion to current/voltage signals. Key variations include:

• Linearized vs. Non-Linearized Thermocouples: The OM7-37 series provides non-linearized thermocouple inputs with raw voltage outputs, while the OM7-47 series offers linearized temperature output for specific spans and types (including Type N).
• RTD Material Support: Standard OM7-34 modules are configured for Platinum RTDs (alpha 0.00385), whereas the OM7-34-N sub-series is specifically designed for Nickel RTDs.
• Output Signal Types: Most input modules provide voltage outputs selectable as 1 to 5 V or 0 to 10 V via part number modifiers (e.g., -1-C vs. -2-C). Dedicated output modules include OM7-22 for ±10 V buffering and OM7-39 for current loop conversion.
• Bandwidth & Response: High-speed voltage input module OM7-21 offers a 3 dB bandwidth of 300 Hz with a 1 msec response time, whereas thermocouple modules (OM7-37/47) have lower bandwidths (3 Hz) and slower response times (150 msec).
• Loop Power: The OM7-35 module uniquely provides isolated loop power for 2-wire transmitters, distinguishing it from passive current input modules like the OM7-32.