H-4161 SDI-12 to 4-20mA Interface
WQ600 Oxidation Reduction Potential Sensor
Global Water's 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. 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. 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.
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 H-4161 includes:
- 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
Specifications
| 4-20mA Current Transmitter | |
|---|---|
| Type | 2-wire, loop-powered |
| Isolation | 1000V r.m.s min |
| Loop Voltage | 5.5V min, 35V max |
| Resolution | 16 bits |
| Non-linearity | ±0.01% of FS max |
| Offset Drift | ±25ppm of FS/ ° C max |
| Power Requirements | |
|---|---|
| Voltage Input | 9 to 16 Volts DC |
| Surge Protection | Built-in, 1.5 KVA |
| Supply Current | Sleep mode: 2.1 mA typ Active: 8.0 mA typ |
| SDI-12 Ports | |
|---|---|
| Baud Rate | 1200 |
| Protocol | SDI-12, 7-bit even parity, 1 stop bit |
| Output Voltage Levels | Minimum High Level: 3.5 volts Maximum Low Level: 0.8 volts |
| Response Time | |
|---|---|
| SDI-12 measurement sequence | aM!: 0-seconds, 1-parameter all other: 1- second, 1-parameter |
| LCD Display | |
|---|---|
| Type | 2-line x 16-character, reflective |
| Operating Temperature | -0° C to +50° C |
| Storage Temperature | -20° C to +60° C |
| Operating Modes | |
|---|---|
| Monitor | Monitor the SDI-12 port for &"aD0!” commands, update the 4-20mA output |
| Initiate | Initiate measurements on the AuxSDI port update the 4-20 mA output; data is available via &"aM!” on the primary SDI-12 port |
| Transparent | SDI-12 and AuxSDI ports are connected together |
| Environmental | |
|---|---|
| Operating Temperature | -20° C to +50° C |
| Storage Temperature | -20° C to +60° C |
| Humidity | Non-condensing |
| Mechanical | |
|---|---|
| Material | ABS plastic |
| Size | 3.75" Long x 2.65" Wide x 1.25" Deep |
| Connections | |
|---|---|
| +12V, SDI-12, AuxSDI | 5-position plug-in terminal strip, Phoenix Combicon (provided) |
| 4-20mA | 2-position plug-in terminal strip, Phoenix Combicon (provided) |