11
Design and Theory of Operation
SIGMA Manual Number 41019
Revision AA
Audible Alarm Device and System
The audible alarm device is a 1-inch moving coil speaker. The speaker is driven by two separate
audio paths, one by the Sharp and one by the PIC. Either the Sharp or PIC can independently sound
an audio alarm tone if an alarm occurs or a fault is detected.
Electronic Components
AC Power Adaptor / Charger
The SIGMA Spectrum infusion pump uses an AC power adaptor capable of providing 9 VDC. The
power adaptor connects to Spectrum via a positive locking connector, which will reduce the possibil-
ity of accidental disconnection. When the AC power adaptor is plugged into an AC receptacle, the
lithium ion battery pack will be charged. Normal charger operation occurs as follows: If the battery
requires charging, the Spectrum battery charger will initially maintain the battery at a constant cur-
rent of approximately 250 mA (400 mA if pump is non-wireless or wireless is turned off). After the
battery voltage reaches a nominal charge of 8.3 volts, the charger maintains this voltage until the
charging current supplied to the battery is less than 60 mA. The battery charge cycle is completed
and will terminate. There are three mechanisms employed to prevent overcharging of the battery:
■
The charging microcontroller’s ability to monitor and control voltage and current applied to
the battery.
■
A current clamp circuit is employed to prevent charge currents that would cause charge cir-
cuit overheating.
■
Battery pack protection circuits within the battery pack itself prevent overheating and over
charging.
The adaptor side of the AC power adaptor is equipped with a Protector (P/N 45742). The Protector
is a plastic enclosure which snaps onto the adaptor. The purpose of the Protector is to protect the
adaptor from damage during use in a hospital environment. The AC power adaptor with the Protec-
tor can be used on wall outlet and pole mount power strip receptacles. The Protector comes installed
with the pump. The Protector cannot be removed from the adaptor once it is installed. The Protector
can be ordered separately as an accessory for installing on an old AC power adaptor. A separate
instruction bulletin on how to install the Protector is sent along with the Protector.
The Protector is compatible with the cleaners mentioned in this Service Manual. Refer to “SIGMA
Spectrum Cleaning” on page 26 of this Service manual for cleaning methods and compatible cleaners
that can be used on the Protector.
CAUTION:
IMPROPER REMOVAL MAY DAMAGE THE AC POWER ADAPTOR.
Remove
the AC power adaptor by grabbing the handle of the Protector and pulling it back
off the receptacle. Do not pull the cord to unplug the Adaptor from the receptacle.
Improper twisting or pulling of the connector or cord may damage the AC power
adaptor.