Lake Shore Model 331 Temperature Controller User’s Manual
4.16.3 Analog Output In Loop 2 Mode
In Loop 2 mode, the analog output is directly controlled by Model 331. To place the analog output in
Loop 2 mode, press the
Analog Output
key, then press the
s
or
t
key until you see the following
display.
Select With °®
Analog Out Loop 2
Press the
Enter
key. The next screen is for control of Bipolar Mode.
Select for Loop 2 °®
Bipolar Mode Off
Press the
s
or
t
key to toggle between Bipolar Mode Of or Off. Bipolar Mode On allows the control
output to go negative. This is only needed when controlling a thermoelectric device. For most cases,
Bipolar Mode should be Off. Press the
Enter
key. The instrument returns to the normal display.
4.17 LOCKING AND UNLOCKING THE KEYPAD
The keypad lock feature prevents accidental changes to parameter values. When the keypad is locked,
some parameter values may be viewed, but most cannot be changed from the front panel. Alarm Reset
and Heater Off are the only keypad functions that remain active when the keypad is locked.
A 3-digit keypad lock code locks and unlocks the keypad. The factory default code is
123
. The code can
be changed only through the computer interface. If instrument parameters are reset to default values,
the lock code resets also. The instrument cannot reset from the front panel with the keypad locked.
To lock the keypad, press and hold the
Enter
key for 10 seconds to display the screen shown as
follows.
Enter Code To
Lock Keypad
Use the numeric keypad to enter the 3-digit lock code. The keypad locks and the normal display
appears. Changes attempted to any parameters result in a brief display of the *LOCKED* message.
To unlock the keypad, press and hold the
Enter
key for 10 seconds to display the screen shown as
follows.
Enter Code To
Unlock Keypad
Use the numeric keypad to enter the 3-digit lock code. The keypad unlocks and the normal display
again appears. All Model 331 parameters are now accessible.
Operation
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