5.10 Start Verification Command: aV!

This command tells the WLTS to return a verification (self-test) code in response to a subsequent aD0! command. In this case, the WLTS returns a non-zero time because the self-test execution verifies all internal memory checksums and these operations take about 13 seconds. A typical session would appear as follows:

0V!00131<CR><LF> indicates that one status reading will be ready in about 13 seconds.

0<CR><LF> is a service request from the WLTS within 13 seconds to indicate that the BIT operations are complete and the verification code is available.

0D0!/0+000<CR><LF>) is the Send Data command from the SDI-12 recorder to obtain the BIT verification code of "+000" which indicates that no faults were found. The possible fault codes are shown in Table 5-1. All the decimal representations of the individual faults are summed to arrive at the resultant BIT verification code. An included bit in a certain bit position means the corresponding test has failed.


Code Bit Position Decimal Representation Test Meaning
0 1 N/A
1 2 WLTS Program Flash Checksum
2 4 WLTS Information Flash Checksum
3 8 WLTS Bootloader Flash Checksum
4 16 N/A
5 32 N/A
6 64 Test Temperature Sensor
7 128 Test Pressure sensor

Table 5-1 BIT Verification Fault Codes