SDI-12 stands for "Serial Data Interface at 1200 Baud". The SDI-12 support group defines it as a "standard to interface battery powered data recorders with micro-processor based sensors designed for environmental data acquisition". Such sensors are most widely used to monitor soil, water and air parameters.

With the A506 SDI-12 adapter such sensors can easily be attached to Adcon's RTUs of type A723 addIT and A733 addWAVE. The adapter supports up to 20 sensor values. This means that you can either attach 20 sensors, outputting one value each, or e.g. 2 sensor, outputting up to 10 values each.

Through the A506 the sensors can even be supplied with power. Please observe that an Adcon RTU can only feed 6V DC to the sensor, so external power like a 12V lead battery might be required. Most SDI-12 multi parameter probes nowadays come by default with integrated battery packs.

Installation:
The 5-pin Binder connector of the A506 adapter plugs into the power port of your RTU, while the solar panel now plugs into the SDI-12 adapter. Thus you do not loose any of the standard I/O ports of your RTU! The SDI-12 sensor values are added to your RTU's logging capability, making an A733 addWAvE a 40 channel data logger - twice as many as before!

The SDI-12 bus cable is fed into the adapter through an IP-67 cable gland, and the wires connect to the adapter's main board via easy to operate cage clamps. By default the sensor comes with 10m of shielded cable.

The SDI-12 advantages:
SDI-12 is a standardized protocol, which defines not only the physical connection between two or more SDi-12 devices, but also determines the "language" in which these devices talk to each other. This is a major advance over proprietary protocols as normally used with RS-232 or RS-485 connections. This standardization makes sure that any SDI-12 sensor is compatible to any SDI-12 data logger, without the need to write a device specific driver.

Physically the SDI-12 system is a bus system. Therefore several sensors can be hooked up to the very same cable, since each sensor is uniquely identifiable via its own address. This also provides the logger with the capability to "talk" to each sensor individually, and retrieve fast changing parameters more often than others, more inert ones.

It is worth mentioning that, according to the SDI-12 specs, such a bus can be up to 60m (=180ft.) long. Power issues aside this would allow an A723 addIT to operate e.g. 4 multi-level soil moisture probes with 5 sensors each, installed in distances of 20 meters (=65ft.) from each other.

System requirements:
- Adcon RTU of type A723 addIT or A733 addWAVE
- Firmware version 2.1 or higher
- Receiver of type A840 Telemetry Gateway
- Software addVANTAGE Pro
- Please keep an eye on the sensors power consumption.

Ordering Information: 200.733.506

Some SDI-12 compatible sensors:
- Sentek EasyAG SDI-12 and EasyAG TriSCAN
- Sentek EnviroSMART and EnviroSMART TriSCAN
- Vaisala WXT-510 combi sensor
- Stevens Hydra Probe
- OTT PS1, Thalimedes, Kalesto, Nimbus, and others
- Hydrolab Multi-parameter probes