CS200
Control Systems
14
Operation
CS200 Controller Display Guide
Operational Theory
The CS200 SERIES Control System automatically maintains the Liquid Nitrogen (LN
2
) level
and monitors temperature in the Cryostorage freezer. Operational conditions are monitored
and any alarm is triggered if necessary. Operations data is stored in memory on the control
board.
The CS200 CONTROL SYSTEM uses thermistors to measure the LN
2
level within the vessel.
A thermistor is a thermal resistor and its resistance changes as the temperature changes.
When a thermistor is submerged in LN
2
, its resistance will be significantly greater than its
resistance at room temperature. The control can detect this resistance change and determine
the level of the LN
2
within the freezer. The CS CONTROL SYSTEM is designed to work with
an 8-thermistor assembly. There are four thermistors that can be selected to maintain the LN
2
level. These selected thermistors correspond to Low Alarm, Start Fill, Stop Fill and High Alarm.
When the LN
2
level drops below the Start Fill thermistor, the control opens the solenoid valve
allowing LN
2
to enter the vessel. This continues until the Stop Fill thermistor is submerged in
LN
2
at which point the solenoid valve is closed, preventing the flow of additional LN
2
into the
vessel. The Low Alarm, Start Fill, Stop Fill and High Alarm settings can all be changed by the
user through the menu system.
Status Wheel
VFD Graphics Display
shows information about
the freezer
Fill button
usend to open
the valve
Stop Button
used
to close the valve
Mutes
the
audible alarm
Back Button
moves out of the
menu system or
leaves current set-
ting unchanged
Enter/Exit
menu system
Menu Indicator
Valve Indicator
lights
if the valve is open
Directional Buttons
Increment/decrement values or
allow movement through the system
Power Indicator
Power
On/Off
Enter Button
“selects”
a menu choice or setting
#8
Figure 1.0 CS200 Controller Display
Figure 2.0 Factory Default Settings Shown
High Level A
Low Level A
#7
#6
#4
#1
#5
Stop Fill
#3
Start Fill
#2
High Level
Alarm
Low Level
Alarm
Summary of Contents for CS200
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