Heater Output Type (Output 2); Configuration; Max Current And Heater Resistance - Lakeshore 335 User Manual

4.5.1.1 Heater Output Type (Output 2)

Heater Output 2 can be configured either as a standard current source output, which
can provide up to 25 W of power into a 25 ) or 50 ) heater, or as a voltage output,
which can provide up to 1 W of power into a 100 ) heater. The Output Type parame-
ter, only available for Output 2, determines which type of output and which rear
panel connector is used.
Menu Navigation:
Output SetupQOutput 2 QOutput Type (Current or Voltage)
Default: Current
Interface: HTRSET
4.5.1.2 75 W Configuration
The Model 335 can provide a total of 75 W of power. In the standard configuration,
Output 1 can provide up to 50 W and Output 2 can provide up to 25 W into either a 25
) or 50 ) heater. Alternatively, when Output 2 is configured as a voltage output, its
power can be diverted to Output 1, which can then provide up to 75 W into a 25 )
heater. In this configuration, Output 2 can still provide 1 W into a 100 ) heater.
Follow this procedure to configure Output 1 for up to 75 W.
1. Set the Heater Output Type setting for Output 2 to Voltage.
2. Ensure that the Heater Resistance setting for Output 1 is set to 25 ). The 1.732 A
(75 W) setting will then be available for the Max Current setting on Output 1.
3. Apply this setting (1.732 A (75 W) setting) to get the desired 75 W output.
4. Alternatively, the User setting can be used for the Max Heater Output setting to
set the maximum current to any value from 0.1 A to 1.732 A.
Once a Max Current setting of more than 1.41 A is applied, the Heater Output Type for
Output 2 cannot be set back to Current until the Max Current setting for Output 1 is
reduced to 1.41 A or less. Refer to section 4.5.1.1 for information about the Heater
Output Type setting. Refer to section 4.5.1.3 for information about the Max Current
and Heater Resistance settings.

Configuration

Output
Output 1
50 W + 25 W
Output 2
Output 1
75 W + 1 W
Output 2
TABLE 4-10 Heater output configurations
Menu Navigation:
Output SetupQOutput 2QVoltageQ
Current (0.1 A to 1.732 A)
Default: Current
Interface: HTRSET

4.5.1.3 Max Current and Heater Resistance

The Model 335 heater outputs are designed to work optimally into a 25 ) or 50 )
heater. The Heater Resistance and Max Current parameters work together to limit the
maximum available power into the heater. This is useful for preventing heater dam-
age or limiting the maximum heater power into the system. When using a 25 ) or
50 ) heater, set the Heater Resistance parameter accordingly. The Max Current set-
4.5.1 Heater Outputs
Source output Power
Up to 50 W
Current
Up to 25 W
Current Up to 75 W
Voltage 1 W
QOutput SetupQOutput 1Q
ENTER
55
Heater
25 ) or 50 )
25 )
100 )
Q Max
ENTER
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