IOTA ISD Series Installation And Operation Description

The ISD Series of emergency lighting battery packs from IOTA Engineering have been designed to ensure that
the pack is always ready in the case of the need for emergency lighting. It accomplishes this by continuously
monitoring the charge circuit and battery voltage and performing its own periodic functional testing at intervals
and durations that meets or exceeds regulatory standards for emergency battery packs. The ISDs also contain
additional features that make installation and use more convenient. Among these features are a single wire to
connect the un-switched power source from 120 to 277VAC at 50 or 60Hz, occupation awareness sensing that
serves to prevent testing during times when the room or office is occupied, a time delayed enabling of the
normal AC ballast to help ensure that the unit is compatible with almost any type and manufacture of AC
ballast, and a watch dog timer that will reset the micro-controller should it ever lock up or freeze due to code
execution errors or electrical line irregularities.
The ISD battery pack should be installed using the installation instructions and wiring diagrams included in the
instruction manual. When this is complete, the ORANGE wire will be connected to the un-switched power
source and the BLACK wire will be connected to the switched (or un-switched if applicable) source that is used
to operate the AC ballast normally. The BROWN wire then powers the AC ballast. This way the ISD will be able
to properly determine the operating voltage (120 to 277) and the occupancy status (when applicable) by
sensing the light switch condition.
When the unit connectors are not connected, the ISD is in a sleep state and consumes a negligible amount of
current. When the unit connectors are mated, the ISD awakes and reads some configuration data from the
EEPROM. This data includes a random 'Days' variable that is set between 1 and 28 at the factory and is
thereafter incremented once every 24 hours while the unit is operating. A random test number is also set at the
factory and is between 1 and 12. The ISD then initializes the I/O pins and a pseudo real time clock that will
keep track of seconds, minutes, hours, days, and months. Once the initialization is complete, the unit will enter
the Start Up state where it will perform the following functions:
Determine the charge current to the battery.
Determine the reason for start up (i.e. unit connectors mated, battery failed during a test or emergency,
the watchdog timer timed out, or a test completed).
Once the charge current is stable between the upper and lower threshold charge currents, the ISD unit will
enter the Charge state where it will spend the vast majority of its life. In the Charge state, the unit will continu-
ously perform the following functions:
Light the LPTS 'green' to indicate the unit is operating normally.
Enter the Emergency state if a loss of AC power is detected.
Monitor the charge current and battery voltage.
Update the pseudo real time clock (PRTC).
Monitor and update the status of the lighted push button test switch (LPTS).
Compare the PRTC day with 26. If it is equal to or greater than 26 set the unit will perform a test within
2 days.
Monitor the occupied status line, the hours to charge variable, and the hour's unoccupied variable. If all
these are clear, it is OK to Test.
ISD-80, ISD-420-EM-A, ISD-420-EM-B Operational Description
Overview
Installation
Details