SonTek/YSI Argonaut-XR Technical Manual - HydroScientific West

Section 6. Operational Considerations
6.1. Input Power Supply
Argonaut Operation Manual Firmware Version 7.9 (May 1, 2001)
SonTek/YSI
The Argonaut processor operates on 7-15 VDC input power. Power consumption during data
collection varies with configuration and operating parameters (see §7.2 for details). If the input
voltage is less than 7 V, the Argonaut will not operate reliably. A supply voltage greater than
15 V to the processor will seriously damage the Argonaut electronics. The Argonaut measures
and stores the input voltage; this can be accessed from the direct command interface (§3.12) and
the output data samples (§3.16, Appendix 1, and the Argonaut Software Manual).
When running from externally supplied power, the input voltage is passed through an additional
voltage regulator before going to the Argonaut processor. This regulator has a maximum voltage
output of 12 VDC for input voltages to 24 VDC.
The additional regulator allows the use of an external power supply from 12 to 24 V. It also
increases system power consumption during data collection and in sleep mode. For real-time data
collection from an external supply, the difference in power consumption is typically not
significant. For autonomous operation from battery power, the increase in power consumption
caused by the additional regulator is typically high enough to affect deployment planning.
Battery power is normally wired directly to the Argonaut processor for autonomous deployments.
For the Argonaut MD, with the batteries mounted in the same housing as the processor, the
internal wiring is constructed for this arrangement at the factory. Battery power is always routed
directly to the processor with no loss of efficiency.
For the Argonaut XR and SL, the underwater connector on the processor housing is wired with a
separate input pin for battery power. This pin is wired directly to the Argonaut processor,
bypassing the additional voltage regulator. The Argonaut XR and SL, with the SonTek supplied
external battery pack and splitter cable, make use of the flexible input power wiring (§5.5.2). The
power from the batteries is wired directly to the processor while the external supply (through the
power and communication cable) is wired through the additional regulator.
IMPORTANT: If providing power directly to the Argonaut through the separate battery power
pin, do not to exceed the 15 V maximum input voltage. Placing a higher voltage through this pin
will seriously damage the Argonaut processor. If using a supply voltage greater than 15 V, route
the power through the external supply pin. See §5.5.1 for connector wiring.
When running the Argonaut from batteries, keep track of battery capacity to prevent the loss of
data because of insufficient power. The internal recorder uses a solid state EEPROM for data
storage that is not affected if the batteries are drained. See §7.2 for details about estimating
power consumption and battery life.
6.2. Real-Time Clock Backup Battery
The Argonaut also includes a backup battery (mounted on the processor – see §5.3) to power the
system clock when main power is unavailable. This battery can be expected to last for many
years. If the backup battery dies, the system clock will reset when main power is disconnected.
Contact SonTek directly before attempting to replace the battery.
Note that when the Argonaut power supply is cycled (turned off and on), it will enter whatever
mode it was previously in (command, data acquisition, deployment). See §3.3 for details.
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