Lake Shore Model 321 Autotuning Temperature Controller User’s Manual
6-6
Service
6.6 ERROR
MESSAGES
On power up, the Model 321 does a check of the internal memory. There are two potential error
messages. The first is usually recoverable, the second is not. The first error display is shown below.
This indicates than an attempt to read the internal non-volatile RAM for the Model ID was
unsuccessful. In some situations, this error can be corrected by the user by initializing the
Model 321 memory. There are three methods that can be used to reinitialize the instrument: (1)
Press the Escape key when the error message is being displayed, (2) hold the Escape key down
when the instrument is off and then turning the instrument on, or (3) holding the Escape key
down for more than 5 seconds. Wait until a message is given before releasing the key.
The second error display is shown below.
This error message indicates that an attempt to write and then read the internal non-volatile RAM was
unsuccessful. This error is not correctable by the user. Please consult the factory.
There are two additional error messages associated with the sensor input. If an input signal from the
sensor exceeding full scale is applied to the input leads, an overload condition is present and is
indicated by “OL” on the display, as shown below.
If no signal or a signal of the wrong polarity is present at the input leads, a Zero Error is indicated by
“Er27” on the display, as shown below.
