TROLL 9500 Operator's Manual - Geotech Environmental Equipment

Section 19: SDI-12 Operation• If a sensor port is empty, the unit will report readings with values of0.0.• If you edit the device to set SDI-12 mode preferences, as describedin the tip ✔ above, only the parameters you select will bereported.• If a sensor is reading out of its range, a value of -999999.9 will bereported.Redundant Logging (Win-Situ 4 and SDI-12)If your MP TROLL 9500 supports internal logging, the instrument iscapable of running tests (programmed in Win-Situ) while participatingin an SDI-12 network; however Win-Situ cannot communicate with theMP TROLL 9500 while it is trans mitting SDI-12 data, and conversely,the instrument cannot receive or respond to SDI-12 commands whileconnected to a PC serial port.This “redundant logging” feature means• if the SDI-12 recorder somehow “loses” data, the MP TROLL 9500data can be retrieved using Win-Situ.* if the SDI-12 recorder ceases to function due to power loss, the MPTROLL 9500 will continue to collect new data using its own internalbatteries and clock.Extended (ISCO) CommandsExtended commands allow the data sampler to identify both the datachannels and channel units that correspond to the ASCII formattedfloating point data being returned. In response to the “aXPR0!” command,the response will be in the form: “aIxIxIx...” where ‘a’is the address, each ‘I’ is a parameter identifier, and each ‘x’ specifiesthe units for the preceding ‘I’.The data sampler will first issue either a measure or a concurrentmeasure command. These commands return the number of channelsthat will be reported in a subsequent read command. This numberwill correspond with the number of pairs returned by the extendedcommands.If the expected number of “Ix” pairs is not returned in response to the“aXPR0!” command, additional “aXPRx!” commands will be issueduntil all pairs are received.ReferenceSDI-12, A Serial-Digital Interface Standard for Microprocessor-BasedSensors, version 1.3. SDI-12 Support Group, Logan, Utah, April 7,2000. Available at www.sdi-12.org.TIP: Depending on the SDI-12 data recorder used, rapidsample schedules during a test may result in SDI-12“retries.”TROLL 9500 Operator’s Manual 1320095110 rev. 007 01/09