MKS 651C, Instruction Manual, Page: 117 / 172

Chapter Eight: Valve Failsafe Battery Back-up
Option Startup
103
Startup
Threshold Voltage Check
When the 651 controller is turned on, it measures the voltage at the input port assigned to the
battery back-up module. When the voltage level at the port exceeds a factory set minimum
threshold value, the controller recognizes that the battery back-up is present, and the software
menus which support the module are installed. Should the voltage level be below the threshold,
the controller does not recognize the module and the software menus are not installed.
Once the 651 unit has been powered up and the battery back-up module has been recognized, the
actual voltage of the battery is measured.
Battery Voltage Within Range
If the battery voltage is within the acceptable range of 11 V to 15.5 V, the instrument revision
and the current software/firmware version appears on the front panel display for about five
seconds, before advancing to the default Pressure and Position screen:
651C
V 1.8
Figure 9: Initial Display Screen
PRES 4.90 Torr
POS 35.0 %
Figure 10: Default Pressure and Position Screen
The controller is now ready for valve connection and setup (or normal operation once the system
has been configured). The 651 unit does not display a status screen to indicate that the battery
voltage is within range.