Specifications. Omega OM-USB-TEMP

OM-USB-TEMP User's Guide Specifications

Channel configurations

Table 2. Channel configuration specifications

Sensor Category Conditions Max number of sensors (all channels configured alike)

Disabled

Thermocouple

Semiconductor sensor

RTD and thermistor

Note 1:

Note 2:

Note 3:

2-wire input configuration with a single sensor per channel pair

2-wire input configuration with two sensors per channel pair

3-wire configuration with a single sensor per channel pair

4-wire input configuration with a single sensor per channel pair

4-wire input configuration with two sensors per channel pair

8 differential channels

8 differential channels

4 differential channels

8 differential channels

4 differential channels

4 differential channels

8 differential channels

Internally, the OM-USB-TEMP has four, dual-channel, fully differential A/Ds providing a total of eight differential channels. The analog input channels are therefore configured in four channel pairs with CH0/CH1 sensor inputs, CH2/CH3 sensor inputs, CH4/CH5 sensor inputs, and

CH6/CH7 sensor inputs paired together. This "channel-pairing" requires the analog input channel pairs be configured to monitor the same category of temperature sensor. Mixing different sensor types of the same category (such as a type J thermocouple on channel 0 and a type T thermocouple on channel 1) is valid.

Channel configuration information is stored in the EEPROM of the isolated microcontroller by the firmware whenever any item is modified. Modification is performed by commands issued over USB from an external application, and the configuration is made non-volatile through the use of the EEPROM.

The factory default configuration is Disabled. The Disabled mode will disconnect the analog inputs from the terminal blocks and internally ground all of the A/D inputs. This mode also disables each of the current excitation sources.

Compatible sensors

Parameter

Thermocouple

RTD

Thermistor

Semiconductor / IC

Table 3. Compatible sensor type specifications

Conditions

J: -210 °C to 1200 °C

K: -270 °C to 1372 °C

R: -50 °C to 1768 °C

S: -50 °C to 1768 °C

T: -270 °C to 400 °C

N: -270 °C to 1300 °C

E: -270 °C to 1000 °C

B: 0 °C to 1820 °C

100 ohm PT (DIN 43760: 0.00385 ohms/ohm/°C)

100 ohm PT (SAMA: 0.003911 ohms/ohm/°C)

100 ohm PT (ITS-90/IEC751:0.0038505 ohms/ohm/°C)

Standard 2,252 ohm through 30,000 ohm

TMP36 or equivalent

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