The H-4161 features a microprocessor, an LCD display, a 16-bit digital-to-analog converter, a precision voltage reference, and a 4-20mA current transmitter. The SDI-12 and 4-20mA sections are electrically isolated using a high-voltage digital opto-coupler. Data from the SDI-12 bus is scaled by the microprocessor into a 16-bit value and sent to the digital-to-analog converter, which directly controls the current transmitter. The H-4161 has two SDI-12 ports: the primary port manages data monitoring and communication with the device, while the auxiliary port is used when the H-4161 is programmed to initiate measurements, allowing it to collect data from a connected sensor.
The "SDI-12 Serial-Digital Interface" is ideal for data logging applications that require:
- Battery-powered operation with minimal current drain
- Low system cost
Key features of the H-4161 include:
- Precision 16-bit 4-20mA current output
- 1000V isolation between the output and the SDI-12 bus
- Ability to monitor the SDI-12 bus for specific sensor addresses and data parameters
- Capability to initiate measurements from connected sensors
- Programmable "Max" and "Min" data set points for automatic data scaling
- Manual adjustment of the 4-20mA output using extended SDI-12 commands
- Two SDI-12 ports for versatile operation