Operating Manual

IRS31Pro-UMB Operating Manual V10 / 01.2020
G. Lufft Mess- und Regeltechnik GmbH 52
18.5 Communication in SDI12 Protocol
The communication in the SDI-12 mode of the IRS31Pro-UMB is conforming to the standard defined in
‚SDI-12 A Serial-Digital Interface Standard for Microprocessor-Based Sensors Version 1.3 January 12,
2009‘ .
The station may be operated in bus mode together with other SDI-12 sensors, connected to one SDI
master (logger).
18.5.1 Preconditions for SDI-12 Operation
As the interface settings defined in the SDI-12 standard are significantly different from the UMB default
settings the related parameters have to be set properly by the UMB Config Tool.
The protocol mode of the station has to be set to “SDI-12”. The sensor will set the required interface
parameters (1200bps, 7 bits, even parity) automatically.
Measurement data can be transmitted alternatively in metric or US units. Additionally the transmission of
spot values or average values can be selected. The selection is done by the UMB Config Tool.
Attention: When connecting the sensor to a SDI12 logger make sure to see chapter 7.3.1 first!
When operating the device in SDI-12 mode it is basically no more possible to access the device with the
UMB Config Tool, due to the different interface parameter settings. To enable configuration access
nevertheless the interface is operated in standard UMB mode (19200 8N1) for the first 5 seconds(*) after
reset / power on. If a valid UMB telegram is received within this 5 sec, the device will stay in UMB mode
for the configured timeout (several minutes) so that the configuration can be modified.
 Connect the PC to the sensor through an RS-485 converter (e.g. ISOCON)
 Start the UMB Config Tool and create an IRS31Pro-UMB with the address of the actual device
and activate at least one channel. Start the measurement with a measuring rate of 5 sec or faster
(will report connection error at first)
 Reset the device (Power off / on)
 When measurement values are received the measurement can be terminated, the interface is
now open for configuration.