Nor-Cal Intellisys Adaptive Pressure Controllers - Manual (Page 41)

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APC-OP-LIT 1/12
11.0 - battery back-Up
Some APC models are available with a power safe battery back-up option. When installed, this feature will drive the valve closed in the event of a power
interruption to the APC controller. This is more commonly of interest when throttling gate- or pendulum valves are used, because these valves typically also
serve as the vacuum line isolation valve. The following describes the general functionality and specifications of the battery back-up feature.
Battery Back-up Activation and Operation
The APC controller software continuously monitors the operating voltage
delivered to it by the internal PSM. If that voltage drops below a certain
threshold level for more than 50 msec, then the APC disconnects all external
power outputs (such as ±15 VDC), exits its present operational state and
drives the valve closed using battery power. Once the valve is closed, the
APC disconnects itself altogether and shuts down.
Valve Close Speed
The speed at which the valve closes under battery
power is the same as during normal operation.
Resuming Normal Operation
Once normal power is back on, the APC controller will reinitialize the valve
and be ready for operation after about 30 seconds. However, if the APC
controller is configured with the valve initialization safety lock function, then
the
JC serial command needs to be issued before valve initialization can occur.
Alternatively, pull the appropriate \Valve Initialization Enable In\ TTL pin
low to activate the initialization routine.
Battery Pack Information
Specially packaged 15-cell, 18V 500 mA·H Ni-Cd battery assembly.
Battery Life
Depends on various factors including temperature, number of discharge
cycles, battery age, starting charge and valve type. Generally, however, a
new freshly charged battery should close a typical gate- or pendulum valve
ten times, or more, without being depleted to the point where full
actuation is no longer possible.
Recharge Time
Depends on various factors including battery age, state of discharge and to a
lesser degree temperature. Under normal conditions, a fully depleted battery
should charge completely in approximately 5 hours. Recharging occurs auto-
matically provided that the battery is still capable of being charged.
Battery Status
The battery voltage can be read by issuing the RS232 serial command GP . The
controller will respond with the internal Power Supply Module (PSM) output
voltage, the battery voltage and the internal APC temperature as measured on
the main PCB.
NOTE: The battery voltage reported may not be a true
indication of the battery’s condition, because the voltage is read
while the battery is in an unloaded state. Nor-Cal recommends
replacing the battery at least every 1 to 2 years irrespective of
apparent condition or usage history. Please refer to
Appendix I for ordering information. Always obtain
replacement battery packs from Nor-Cal Products.