Xylem H-310 - Manual (Page 17)

Chapter 3
Operation
H-310
Operation 3-1
3.1 Operation
The W ATER LOG ® H-310 is easy to use and works with many data recorders. Its internal
microprocessor automatically compensates for error due to offset, non-linearity, and temperature
changes. The H-310 outputs pressure and temperature measurements in psi units and degrees
centigrade.
SPECIAL NOTE: The W ATER LOG ® H-310 is a very sensitive instrument with special
temperature sensing circuitry. Thus, if you desire the most accurate readings from your
H-310, allow 10 to 15 minutes after installation for the system to come to a thermal
equilibrium with the submerging medium.
The W ATER LOG ® H-310 has advanced features that allow the user more flexibility than
previously in the W ATER LOG ® H-300. These features are as follows:
1. Programmable slope and offset. This feature allows the user to send an extended
SDI-12 command from the data recorder or P.C. terminal program to the H-310 that
will change the pressure output units from psi to feet or meters or the units you choose.
The offset command allows the user to add to or subtract a fixed offset from the
output. This allows the data to be referenced to a datum point, or other reference
point.
2. Fast SDI mode. This mode allows the user to collect data at a 1 second interval
versus the standard 8 second interval. However, the + 0.02% FSO accuracy will not
be maintained in this mode. Also, the H-310 will be at maximum power consumption
continuously. This mode is set by using an extended SDI-12 command.
3. Zero Offset Command. This extended command allows the user to perform an
automatic zero pressure calibration. After the sensor is removed from the water and
allowed to drain, the extended zero offset command will cause the H-310 to perform a
zero calibration measurement. The new zero offset value is stored in EEPROM
internal to the H-310. The sensor can be immediately returned to service. This
command can also be used while the sensor is in place to reference the zero reading to
where the sensor is located.
These extended commands are described in full detail in Appendix D of this manual.