15
The lock feature on your SD card is engaged. You need to unlock it before using the card.
The HHTFO is running from the internal batteries. Icon indicates the approximate amount of
charge remaining. When almost fully empty, the message “LOW BATTERY” is also
displayed, for about 5 to 15 minutes, before auto-shutting off without further warning.
Note: This display is only valid when rechargeable batteries (NiMH or NiCd) are used; if you
are using non-rechargeable alkaline batteries, the charge remaining will quickly drop
towards the end of life of these batteries.
4.8 Power jack
Omega Engineering recommends that you always use the supplied 6VDC power supply module. If you use a
different supply module, it must supply a DC voltage ranging from 5.2 to 6.8VDC; the center pin is the +
contact. If you accidentally use a DC supply that has a voltage outside this range (max of 28 VDC), this
should cause no harm to the HHTFO.
The internal batteries cannot be charged by this module; to charge your batteries, you need to remove them
from the HHTFO, and use a separate charger; alternatively, you can also use non-rechargeable batteries,
size AA.
Compatible battery types are AA alkaline, Ni-Cd and Ni-MH.
4.9 Probe connector
This ST connector mates to an Omega Engineering temperature probe.
4.10 RS232 communication interface
This port is used to configure and download information from the thermometer. The pin-out is standard for
connection to any PC computer COM ports. Use a simple pin-to-pin wired cable (not a null modem cable) to
connect to your computer. Baud rate is fixed at 9600. See Section 6 for a complete description of the serial
commands that are available.