44430A Agilent Data Logger

Additional Features:

• Dual Current D/A Module
• Option 130 for the 3497A Series Data Acquisition/Control Unit
• Analog output: 12 bits
• Least significant Bit: 5 µA (0-20 mA range); 4 µA (4-20 mA range)
• Output current range: 0 to 20.475 mA or 4 to 20.380 mA (each source jumper selectable)
• Ripple and Noise: 5 µA rms, 20 Hz to 250 kHz into 100 ohms
• Compliance Voltage: 12.0 volts
• Load Regulation: +/- 2.0 µA (2.0 V to 12.0 V)
• Monotonicity: Over operating range (Monotonicity guarantees that the output will never change in a direction different than that programmed)
• Isolation Voltage: >170 V peak between any terminal and chassis
• Protection: Can withstand indefinite open or short circuit

The 44430A provides two 0-20 mA or 4-20 mA programmable current sources. It is Option 130 for the 3497A Series Data Acquisition/Control Unit. Each channel outputs a DC current with programmable range from 0 to 20.475 mA in 5 µA increments (for the 0-20 mA range) or from 4 to 20.380 mA in 4 µA increments (for the 4-20 mA range).

Each current source is isolated from the other and from ground which breaks possible ground loops and permits control of devices floated up to 170 volts above ground. Each source can be configured to operate in the 0-20 mA or 4-20 mA range.

The 44430A assemblies, especially when the 4-20 mA range is used, can be used as transmitters in industrial current loops. Each output will drive an industrial current loop with up to 600 ohms of total loop resistance.

The 44430A Current D/A Converter consists of a single board with a current source terminal block and a piggy-back board. The current source terminal block has connectors for a current source (SOURCE) and current sink (SINK) for each of the two channels (channel 0 and channel 1).

The assembly is a programmable constant current source which has an output range from 0 to 20.475 mA(in the 0-20 mA range) or from 4 to 20.380 mA (for the 4-20 mA range). For example, if you program the assembly to output 10.000 mA to the load, 10.000 mA will be available at the load (regardless of load voltage drop) as long as the assembly compliance voltage of 12V is not exceeded.

The 44430A assembly is a constant current source for 0-20 mA range, as long as the compliance voltage of 12 volts is not exceeded. This means that the total voltage between the SOURCE and SINK terminals must not exceed 12 volts for the IDAC to supply constant current in the 0-20 mA range. Since the compliance voltage equals the total circuit resistance times the output current, for a 20 mA output the maximum load resistance for the IDAC is 600 ohms and may be less if lead resistance is relatively high.

An important feature of the IDAC is monotonicity. The IDAC has monotonicity over its operating range which guarantees that the output will never change in a direction different than that programmed. For example, if the IDAC is set for a 5 mA output and is then programmed for a 10 mA output, the actual output will not be less than 5 mA. Or, if the IDAC is set for 5 mA and is then programmed for a 2 mA output, the actual output will not be greater than 5 mA.