SDI-12 Protocol Converters and Testers

Protocol Converter Model 6543A
The model 6543A Protocol Converter converts Modbus to SDI-12 requests or converts HSIO data to Modbus data. This allows Unidata dataloggers and third-party SDI-12 sensors to be integrated into process control (PLC, SCADA) systems. Modbus data is in RTU format. Modbus communications are via RS232 or RS485.

Modbus to SDI-12 Conversion:
The model 6543A Protocol Converter acts as a Modbus slave on a Modbus RTU bus. On receipt of certain Modbus commands the Protocol Converter module initiates SDI-12 commands, awaits the response and returns the results as Modbus values. The data returned is selectable as either binary decimal values with a sign delimiter or an IEEE 32bit floating-point values.

Modbus to HSIO Conversion:
The 6543A Protocol Converter can also act as HSIO slave on the HSIO connection from a UNIDATA data logger or Starflow. On receipt of HSIO data the Protocol Converter module stores the HSIO data into memory. On receipt of certain Modbus commands, the Protocol Converter returns the requested memory values as Modbus values. The data returned is an exact representation of the HSIO value/s received.

SDI-12 Tester Model 6412A
SDI-12 Tester is a portable unit which simplifies the setup and fault finding of SDI-12 sensors in the field and on the laboratory bench. It allows sending a variety of commands enabling sensors to be configured and read. It also enables monitoring communications between a logger and sensors(s) on an SDI-12 bus.
The unit has the following functions: monitor bus, query address, acknowledge active, change address, send identification, start the measurement, send data, send extended command and cyclical measure & send data.
6412A SDI-12 tester has also been tested using the NR Systems SDI-12 verifier.

To find SDI-12 communication protocol specifications please visit: SDI-12 Support Group or view Unidata white paper: SDI-12 Serial Digital Interface Standard

SDI-12 Dual Listener Model 6411C
This device assists with integration projects where you may wish to have both a Starlogger and a neon remote Terminal use the same SDI-12 bus.

Normally two SDI-12 masters on the same bus will cause problems, but with this device a master logger can control all SDI-12 communications activity, but if that logger fails, the secondary logger for example, a Neon remote Terminal, can assume command of the SDI bus and can allow the operation of the system to continue in the event of failure.