Lakeshore 336, User Manual

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4.4.9 Curve Selection 57
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4.4.8.2 Update Rate
The update rate for the scanned input channels is dependent on the number of chan-
nels enabled and how many enabled channels are configured for 100 k
)
NTC RTD. The
scanned input channels are scanned at a rate of 10 rdg/s (100 ms/rdg), with the
exception of any channel that is configured for 100 k
)
NTC RTD. Channels configured
for 100 k
)
NTC RTD are scanned at a rate of 5 rdg/s (200 ms/rdg) when other channels
are enabled, or if it is reversing. See TABLE 4-10.
System control performance may be affected by a decreased update rate. Filtering is
affected by a decreased update rate. Refer to section 4.4.10 for more information
4.4.9 Curve Selection The Model 336 supports a variety of temperature sensors manufactured by
Lake Shore and other manufacturers. After the appropriate sensor type is selected
(section 2.2), an appropriate curve may be selected. The Model 336 can use curves
from several sources. Standard curves are preloaded with every instrument and num-
bered 1 to 20. User curves, numbered 21 to 59, can be used when a sensor does not
match a standard curve. SoftCal™ calibrations are stored as user curves, or you can
enter your own curves from the front panel (section 5.8) or computer interface (sec-
tion 6.4). The complete list of sensor curves preloaded in the Model 336 is provided in
TABLE 4-11.
Sensor Type
Available
Range
Settings
Maximum Sensor Power
Sensor
Excitation
Diode
2.5 V (Silicon) 25 µW (at 10 µA excitation) 10 µA, 1mA
10 V (GaAlAs) 100 µW (at 10 µ excitation) 10 µA, 1mA
PTC RTD
(Platinum)
10
)
10 µW
1 mA
30
)
30 µW
100
)
100 µW
300
)
300 µW
1 k
)
1 mW
3 k
)
3 mW
10 k
)
10 mW
NTC RTD
(Cernox)
10
)
10 µW 1 mA
30
)
2.7 µW 300 µA
100
)
1 µW 100 µA
300
)
270 nW 30 µA
1 k
)
100 nW 10 µA
3 k
)
27 nW 3 µA
10 k
)
10 nW 1 µA
30 k
)
2.7 nW 300 nA
100 k
)
1 nW 100 nA
TABLE 4-9 Model 3062 4-channel scanner option range and sensor power
Number of scanner
channels enabled
Update rate
1 10 rdg/s (100 ms/rdg)
2 5 rdg/s (200 ms/rdg)
3 3
1/d
rdg/s (300 ms/rdg)
4 2
q
rdg/s (400 ms/rdg)
5 2 rdg/s (500 ms/rdg)
TABLE 4-10 Model 3062 4-channel scanner
option reading update rate