1.2
Front-Panel Operation
1 – 5
1.2.2.2
Battery charge override
For some applications, it may be important to insure that the SIM928
will not begin a battery switch-over during a particularly sensitive
experiment. The [Battery Override] can be used to force the
Ready
battery to be switched to
On
immediately, ensuring a 12
+
hour period
of un-switched operation.
The [Battery Override] is only armed when one of the batteries is
in the
Ready
state; while a battery is in the
Charge
state, this key
is temporarily disabled. To initiate a forced swich-over, press and
hold [Battery Override] for at least 5 seconds. Over the next few
seconds, the standby battery will be switched in, and the previously
On
battery will be switched to the standby (
Ready
) state—not to the
charger—where it will remain.
1.2.2.3
Service batteries
The nickel-metal-hydride battery packs used in the SIM928 have a
finite lifetime. After around 1000 charge
/
discharge cycles, the re-
maining battery capacity is significantly reduced; to restore the in-
strument to full performance, the battery pack must be replaced. The
yellow
service batteries
indicator turns on when the battery pack has
reached this limit. The SIM928 will continue to operate properly with
reduced-capacity batteries; the only e
ff
ect will be the battery switch-
over will occur more frequently.
It is also possible, if a SIM928 is left in storage for several years with-
out operation, that the batteries will have lost a significant fraction of
their capacity due to aging. In this case, the yellow
service batteries
indicator will
not
turn on, but the user may notice a shorter period
between battery charge cycles. The manufacture date of the battery
pack can be determined with the remote
BIDN?
query.
Replacement battery packs can be ordered from Stanford Research
Systems.
1.2.3
Output
The SIM928 output voltage is available at the front-panel between
the red
+
and black
−
banana jack
/
binding posts. These connectors
accept standard 0.175” in Banana plugs. The binding post accomo-
dates wire leads up to #12 AWG, as well as open spade lugs for #8
studs (0.165” minimum opening).
The lower, green terminal is tied to the SIM928 chassis, and is avail-
able for user grounding. Either output terminal may be tied to chassis
ground, if desired.
SIM928
Isolated Voltage Source
