Arbiter Systems 931A, Operation Manual

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backlight control (the backlight adds approximately 50% to power drain),
use of the timer and transducer inputs, and the measurement function.
931A PC PC Seiko ATENS EPSON Seiko
DPU-411 XP-320 FX-80 DPU-414
DB9F DB9F DB25M DB25M DB25M DB25M DB9M
2 / RXD 3 / TXD 2 / TXD N/C 3 / TXD 2 / TXD 2 / TXD
3 / TXD 2 / RXD 3 / RXD 2 / RXD 2 / RXD 3 / RXD 3 / RXD
4 / DTR N/C N/C N/C N/C N/C N/C
5 / GND 5 / GND 7 / GND 7 / GND 7 / GND 7 / GND 5 / GND
7 / RTS 6 / DSR 5 / CTS N/C 4 / CTS 4 / CTS N/C
N/C 8 / CTS 6 / DSR N/C 20 / DSR 20 / DSR N/C
8 / CTS 7 / RTS 4 / RTS 5 / Busy 5 / RTS 5 / RTS 8 / RTS
Table 2.3: RS-232C Port Pinout / Signal Description
2.7.2 Line Power/Battery Charging
Battery charging occurs whenever power is applied to the Model 931A
main power inlet. The internal charger supplies a steady level of power
to the instrument, whether powered on or off. If the 931A is powered
on, power is split between instrument operation and battery charging. If
using the back light, additional power is directed to the instrument, and
increases the time to charge the NiMH battery. To charge the battery
completely from a depleted state should take approximately 8 hours with
the Model 931A powered off.
Charge only if ambient temperature is
in the range: 0
◦
C – 40
◦
C (32
◦
F – 104
◦
F) .
NiMH battery charging in the Model 931A is monitored and controlled
using three factors: (1) ∆ T / ∆ t , (2) ∆ V / ∆ t , and (3) time.
∆ T / ∆ t : When the cell reaches full charge, most of the charging
energy is converted to heat. This increases the rate of change of battery
temperature, which can be detected by a sensor such as a thermistor.
∆ V / ∆ t : When the battery is fully charged the voltage across its
terminals drops slightly. The charger can detect this and stop charging.
Elapsed Time: Total charge time is monitored and battery charging
stops when the preprogrammed time interval has elapsed.
The low battery state is indicated on the main display by “LOW
BAT!!”, and flashes On and Off. The Model 931A will automatically shut
down if the low battery condition persists for longer than several minutes.
It is recommended that the unit be charged or shut off when it
indicates a low battery condition.
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