82
c
HAPTER
4:
Operation
Model 350 Temperature Controller
The ramping feature is useful by itself, but it is even more powerful when used with
other features. Setpoint ramps are often used with zone control mode. As tempera-
ture is ramped through different temperature zones, control parameters are auto-
matically selected for best control. Ramps can be initiated and status read back using
a computer interface. During computer-controlled experiments, the instrument gen-
erates the setpoint ramp while the computer is busy taking necessary data.
When an incomplete ramp is shut off, the setpoint will remain on the most current setting
(the reading will not jump to the end of the ramp).
If the input type or input curve is changed while a ramp is in progress, both ramping and
the heater are turned off.
If Ramp is on and the setpoint is set to sensor units, the ramping function will remain on
but when another setpoint is entered, the setpoint goes directly to the new setpoint
value.
To bypass ramping and load the setpoint with the current temperature, with the control
loop displayed, press and hold the Setpoint button for 3 s.
Menu Navigation:
Output Setup
Q
Output
(1, 2, 3, or 4)
Q
Setpoint Ramping
Q
(Off or On)
Default: Off
Interface Command:
RAMP
To stop a ramp, when the desired control loop is displayed, press
Setpoint
, then
immediately press
Enter
. This stops the ramp at the current setpoint, but leaves the
ramping function activated. To continue the ramp, enter a new setpoint. Refer to sec-
tion 4.5.1.5.6 for details on setting the Setpoint parameter.
4.5.1.5.8 Heater Range
The Heater Range setting is used for turning a control output on, as well as setting the
output power range for the heater outputs. All four outputs provide an Off setting for
turning the output off. The heater outputs, 1 and 2, provide five ranges of settings
which provide decade steps in power, based on the maximum output power available
to the connected heater. Range 5 provides the maximum power, and each successive
lower range provides 10 times less power than the last. Refer to section 2.14.1 for
details on how to calculate the maximum output power. The analog outputs, 3 and 4,
do not have multiple output ranges, and only provide an On setting for enabling the
output.
While controlling tempertature, the following will cause the heater range to automati-
cally turn off:
D
Exceeding the Temperature Limit setting
D
Setup changes to the control input
D
Power loss with Power Up Enable feature turned off
D
Input errors such as T. Over, T. Under, S. Over, and S. Under
Available full scale current and power for output 1 are determined by the heater resis-
tance, Max Current setting, and Heater Range.
Specifications of the heater outputs are provided in section 1.6. Heater theory of
operation is provided in section 2.4. Various heater installation considerations are
provided in section 3.6.
Summary of Contents for 350
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Page 28: ...14 cHAPTER 1 Introduction Model 350 Temperature Controller ...
Page 53: ...Examples of PID control 2 13 4 ManualOutput 39 www lakeshore com FIGURE 2 4 ...
Page 58: ...44 cHAPTER 2 Cooling System Design and Temperature Control Model 350 Temperature Controller ...
Page 118: ...104 cHAPTER 5 Advanced Operation Model 350 Temperature Controller ...
Page 178: ...164 cHAPTER 7 Options and Accessories Model 350 Temperature Controller ...
Page 192: ...178 cHAPTER 8 Service Model 350 Temperature Controller ...