Instructions

UM-0085-B09 DT80 Range User Manual Page 22

Measurements

What can the DT80 Measure?

Analog

Using its analog inputs, the DT80 can directly measure the following:

• DC voltage (30mV, 300mV, 3V , 50V, (30V – Series 3 or older) ranges)

• DC current (0.3mA, 3mA and 30mA ranges with internal 100 Ohm shunt)

• resistance (10Ω, 100Ω, 1kΩ, 10kΩ (maximum for Series 3 or older), 1MΩ ranges)

• frequency (0.1 to 450,000 Hz (to 10,000 Hz – Series 3 or older))

Many other quantities can be measured by connecting appropriate sensors which convert a physical quantity into

something that the DT80 can measure.

The DT80 directly supports:

• 4-20mA current loop sensors (0 to 100%)

• temperature sensors (thermocouples, RTDs, thermistors, IC sensors)

• bridges and strain gauges

• vibrating wire strain gauges (DT80G/ 85G only)

This list can be extended by means of user specified scaling calculations.

Digital

The DT80’s digital and counter channels allow the measurement of:

• digital input state (contact closure, CMOS or TTL logic)

• pulse count (32 bit)

• phase encoder position (32 bit)

Serial

Various “smart sensors” can also be read:

• SDI-12 (Serial Data Interface – Programmable baud rates) based sensor networks

• other serial sensor devices with an RS232/ 422/ 485 interface, such as weighing machines, barcode scanners

• CAN (Controller Area Network) sensors, using the optional dataTaker CANgate CAN to ASCII gateway device.

The use of this product is outside the scope of this manual.

Analog Channels – Introduction

Figure 2: DT80 analog terminals

Input Terminals

The DT80 provides five analog input channels, numbered 1 to 5. Depending on the wiring configuration used, these allow

between 5 and 15 separate voltages to be measured. The DT81 has one analog input channel, allowing 1-3 separate

voltages to be measured, and the DT82E has two (2-6 separate voltage measurements). Finally, the DT85 has 16

analog input channels, allowing 16-48 separate voltage measurements.

Each analog input channel on a DT80 is a 4-wire connection (see Figure 3) that allows voltage, current, resistance and

frequency to be measured. These are the fundamental signals output by most sensors. It is not necessary to use all four

terminals on each channel— two are often adequate.