Campbell Scientific CR9000X Measurement and Control System - Manual (Page 258)

Section 7. Measurement Instructions
7-34
TDR100 (Dest, SDMAddress, Option, Mux/ProbeSelect, WaveAvg, Vp,
Points, CableLength, WindowLength, ProbeLength, ProbeOffset,
Mult, Offset)
This instruction can be used to measure one TDR probe connected to the
TDR100 directly or multiple TDR probes connected to one or more SDMX50
multiplexers.
Parameter
& Data Type Enter TDR100 PARAMETERS
Dest The Dest parameter is a variable or variable array in which to store the
results of the measurement. The variable must be dimensioned to
accommodate all of the values returned by the instruction, which is
determined by the Option parameter.
SDMAddress The SDMAddress parameter defines the address of the TDR100 with which
to communicate. Valid SDM addresses are 0 through 14. Address 15 is
reserved for the SDMTrigger instruction. If the Reps parameter is greater
than 1, the datalogger will increment the SDM address for each subsequent
TDR100 that it communicates with.
Note: CRBasic dataloggers are programmed using the base 10 address (0-
14) Edlog programmed dataloggers (e.g., CR10X, CR23X) used base 4
Option The Option parameter determines the output of the instruction.
Code Description
0 Measure La/L (ratio of apparent to physical probe rod length)
1 Collect Waveform values - Outputs reflection waveform values as
an array of floating point numbers with a range of -1 to 1. The
waveform values are prefaced by a header containing values of key
parameters for this instruction (averaging, propagation velocity,
points, cable length, window length, probe length, probe offset,
multiplier, offset)
2 Collect Waveform plus First Derivative - Returns (2*n-5)+9 values
where n is the number of waveform reflection values specified by
the Points parameter.
3 Measure Electrical Conductivity - Outputs a value that when
multiplied by the Multiplier parameter determines soil bulk
electrical conductivity in S/m.
Mux/
ProbeSelect The Mux/Probe Select parameter is used to define the setup of any
multiplexers and attached probes in the system. The addressing scheme
used is ABCR, where A = level 1 multiplexer channel, B = level 2
multiplexer channel, C = level 3 multiplexer channel, and R = the number of
consecutive probes to be read, starting with the channel specified by the
ABC value (maximum of 8). 0 is entered for any level not used.