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OM7 Series from $100
Modular Compact Signal Conditioners

• Isolated Signal Conditioners for a Wide Range of Process Control Signals: Thermocouples, RTDs, mA, mV, V

• Process Current (4-20 and 0-20 mA) Output Module

• Powered mA Input Module Includes Isolated +24 Vdc Power for a Remote Transmitter

• Bipolar Voltage Input and Output Modules

• Operates From a Single +24 Vdc Power Supply

• Provides 1-5 V, 0-10 V, and ±10 V Output Options

• ±0.1% Max. Accuracy, Factory Calibrated

• 1500 V rms of CMV Isolation and 120 V rms Field Wiring Protection

• Compact, 54 x 42 x 14 mm (2.1" x 1.7" x 0.6" ) Plastic Housing

  The OM7 Series modular isolation-based, single-channel plug-in signal conditioning system accepts inputs from a wide range of process control transducers and signals while providing high-level output voltages. Featuring a maximum nonlinearity of 0.02% and factory calibrated to guarantee maximum accuracy of ±0.1%, the OM7 Series offers superior performance at a lower cost than multipurpose signal conditioners. The modules provide 1500 V rms isolation and 120 V rms of field wiring input protection. The power supplies necessary to drive each individual module's input circuitry are internally isolated, enabling the OM7 modules to offer true channel-to-channel isolation of the input signals. The modules are rated for a nominal power supply input of +24 Vdc and, for maximum flexibility, will accept supply voltages in the +14 Vdc to +35 Vdc range.

  All modules are packaged in a compact 54 x 42 x 14 mm (2.1" x 1.7" x 0.6") durable plastic case that readily accommodates high channel density applications. Each module may be operated in high humidity (noncondensing) environments and is rated over the extended -40 to 85°C industrial temperature range. All modules feature a simple pinout that allows them to be mixed and matched within a single backplane design. Furthermore, modules are easily serviced since they can be removed and inserted into the backplane with power applied.

  Modules are available to isolate and condition the following input signals and transducers: voltage, process current, RTD, 2-wire transmitter, and thermocouples. The 2-wire transmitter interface module (OM7-35) accepts a 4-20 mA process input and provides an isolated +24 Vdc supply to power the current loop. In this way, a loop-powered transmitter can be directly connected to the OM7-35 without requiring a separate power supply. All of the isolated input modules, with the exception of the OM7-21, provide a high-level output voltage that is factory configured for either the 1-5 V or 0-10 V range. The OM7-21 is a unity gain, isolated input module with an input/output range of ±10 V.

  Modules are also available that provide isolated output signals for process current and bipolar voltage. The OM7-39 process current module converts either a 1-5 V signal to a 4-20 mA output or a 0-10 V input to a 0-20 mA output. The input/output ranges of the OM7-39 are factory configured. The OM7-22 is a unity gain module that provides an isolated ±10 V output signal.

  A full line of backplanes and rack-mount hardware complete the OM7 Series signal conditioning system. Each backplane contains screw terminals for field wiring connections and a miniature cold junction compensation (CJC) thermistor that is installed under the terminal blocks of each channel. Due to the pinout of the OM7 Series modules, the CJC thermistor affects only the thermocouple modules. This flexibility permits any module type to be used in any channel on the backplane.

ISOLATED VOLTAGE AND CURRENT INPUT

The OM7 Series feature five isolated voltage/current input modules capable of addressing a wide variety of input voltage ranges and signal dynamics.

The OM7-21 is a bipolar unit module featuring a full-scale range of ±10 V. The OM7-30 and OM7-31 accept dc input voltages and provide either a factory configured 1-5 V or 0-10 V output signal. The OM7-32 accepts a 4-20 mA process current input signal and provides an output voltage signal in the 1-5 V range. The OM7-33 isolates a 1-5 V input signal and provides a buffered 1-5 V output signal. The OM7-32 and OM7-33 can also be factory configured to provide a 0-10 V output signal with a 0-20 mA or 0-5 V input, respectively. Both the OM7-32 and OM7-33 have bandwidths of 100 Hz. The OM7-30 and OM7-31 are limited to 3 Hz bandwidth.

ISOLATED THERMOCOUPLE INPUT

The OM7-37 and OM7-47 modules accept inputs from types J, K, T, E, R, S, and B thermocouples and provide a 1-5 V or 0-10 V output signal. The OM7-47 also accepts inputs from type N thermocouples. Both the OM7-37 and OM7-47 have a nominal 3 dB bandwidth of 3 Hz, and they provide for upscale open input detection within 10 sec.

In addition to the signal conditioning capabilities of the OM7-37, the OM7-47 includes an internal linearization circuit that compensates for the inherent nonlinearities of the thermocouple. With this linearizer, the OM7-47 is able to provide an output voltage that is linear with respect to the actual temperatures being measured by the thermocouple.

The thermocouple input modules accomplish CJC by means of an external thermistor mounted under the field wiring screw terminal blocks of the backplane.

ISOLATED LINEARIZED RTD INPUT

The OM7-34 module accepts inputs from 100(omega) platinum and 120(omega) nickel RTDs and produce an output voltage signal that is proportional with temperature measured by the RTD. The OM7-34 modules are available in a factory-configured 1-5 V or 0-10 V output range. Three-wire lead resistance compensation is provided and 2- or 3-wire RTDs may be used. The OM7-34 RTD input module has a nominal 3 dB bandwidth of 3 Hz and upscale open
RTD detection with 10 sec.

ISOLATED 2-WIRE TRANSMITTER INTERFACE

The OM7-35 input module accepts a 4-20 mA process current input, provides a standard 1-5 V output signal, and features an isolated loop power supply for driving the current transmitter. The module has a nominal 3 dB bandwidth of 100 Hz and offers downscale open input detection within 2 sec.

The isolated transmitter loop power supply of the OM7-35 is unregulated and will provide a voltage that is proportional to the voltage used to power the OM7-35 module. The voltage provided by the OM7-35 is between 13 V and 34 V for loop current between 4 mA and 20 mA and supply voltages between 20.4 and 26.4 V. (For nominal +24 V supply, the OM7-35 will supply approximately +24 V to the loop.)

ISOLATED CURRENT OUTPUT

The OM7-39 isolated output module accepts either a factory-configured 1-5 V or 0-10V input signal and provides an isolated 4-20 mA or 0-20 mA output current signal. The module can drive a wide range of resistive loads, depending upon +V_s, the supply voltage. At a nominal +V_s of +24 V, the OM7-39 will drive up to 850(omega).

ISOLATED BIPOLAR VOLTAGE OUTPUT

The OM7-22 is a unity-gain module with an input/output range of ±10 V. The OM7-22 has an input range of ±10 V and provides an isolated bipolar ±10 V output signal to the field. The OM7-22 features 1500 V rms of CMV isolation, 100 dB minimum of common mode rejection, and a 400 Hz bandwidth.

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