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Aquaread BlackBox™ Instruction Manual
10401-00618 Rev P
If the measurement time sent by the BlackBox is greater than “000”, the data recorder
should wait for the BlackBox to send a Service Request before sending the Send Data
command.
After sending this response, the BlackBox will relinquish control of the data line and wait for
the data recorder to request the measurements with one or more Send Data commands.
The first Send Data command will have a sequence number “0” and for subsequent Send
Data commands the sequence number will be incremented by 1 (unless data is re-
requested due to a transmission/reception error, in which case the sequence number will
not change).
The size limit of the <values> field in the data response packet may require that the
measurements returned by the BlackBox be split across multiple data responses. The data
recorder will continue to request data packets until it has received the expected number of
measurement values (as reported in the response to the Start Measurement/Additional
Measurement/Start Concurrent/Additional Concurrent Measurement command).
After a Start Measurement or Additional Measurement command & response, the data
recorder may abort the measurement by sending a command to another probe (preceded
by a break frame) or a command other than Send Data to the BlackBox.
After a Start Concurrent Measurement or Additional Concurrent Measurement command &
response, the data recorder may abort the measurement by sending a command other than
Send Data to the BlackBox. (The data recorder may send commands to other probes on
the same SDI-12 bus without aborting a concurrent measurement.)
If the data recorder sends any Send Data command to the BlackBox not preceded by any
form of measurement start command or after aborting a measurement sequence, then the
response will not contain any data values.
On reception of a Continuous Measurement command (with or without CRC request), the
BlackBox will respond with a packet containing appropriate measurements dependent upon
the type of Aquaprobe connected to it and upon the measurement set requested. The
response will also contain a CRC, if requested.
Table 2 details the measurements provided by the BlackBox and the following subsections
describe the contents of the measurement related packets for each type of Aquaprobe.
Field name
Measurement
Units
<baro>
Barometric pressure
mbar
<temp>
Temperature
°C
<ph>
pH
pH
<orp>
Oxidation/reduction potential
mV
<turb>
Turbidity
NTU (Nephelometric
Turbidity Units)
<cond>
Electrical conductivity
µS/cm
<cond20> Electrical conductivity (corrected to 20°C)
µS/cm
<cond25> Electrical conductivity (corrected to 25°C)
µS/cm
<res>
Electrical resistivity
kΩ.cm
<sal>
Salinity
PSU (Practical Salinity
Units)
<tds>
Totally dissolved solids
mg/L
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