3.13 CURVE ENTRY AND STORAGE
The Model 211 has standard curve locations numbered 1 through 20.
At present, not all locations are occupied by curves; the others are reserved
for future updates. Standard curves cannot be changed by the user, and
reserved locations are not available for user curves.
The Model 211 has one user curve location. The user curve can only be
entered using the serial interface. Refer to Paragraph 4.2 for the serial
interface curve commands. The user curve location can hold from 2 to 200
data pairs (breakpoints) including a value in sensor units and a
corresponding value in kelvin.
3.13.1 Curve Header Parameters
Each curve has a set of parameters that are used for identification and to
allow the instrument to use the curve effectively. The parameters must be
set correctly before a curve can be used for temperature conversion.
Curve Number: 1 – 21. Location 21 is for the user curve.
Name: Up to a 15-character name can be entered.
Serial Number: Up to a 10-character sensor serial number consisting of
both numbers and letters.
Format: The format parameter tells the instrument what breakpoint data
format to expect. Different sensor types require different formats.
Formats for Lake Shore sensors are:
V/K: Volts vs. kelvin for diode sensors.
/K: Resistance vs. kelvin for platinum RTD sensors.
Log /K: Log resistance vs. kelvin for NTC resistive sensors.
Limit: Temperature limit in kelvin for the curve. Default is 375 K. This
limit is not used in this instrument but is left in to be compatible with
Lake Shore temperature controllers.
Temperature Coefficient: The unit derives the temperature coefficient
from the first two breakpoints. The coefficient sent by the user is ignored.
If it is not correct when the curve header is queried, check for proper
entry of those points. A positive coefficient (P) indicates that the sensor
signal increases with increasing temperature. A negative coefficient (N)
indicates that the sensor signal decreases with increasing temperature.
The power must be cycled or the *RST command issued for the
instrument to calculate the temperature coefficient after curve points
have been entered.
To Next Page
Loading...
