User`s manual

64 cHAPTER 4: Operation
Model 335 Temperature Controller
4.5.1.7.8 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. Both outputs provide an Off setting for
turning the output off. The heater outputs in Current mode provide Low, Medium
(Med), and High settings, which provide decade steps in power, based on the maxi
-
mum output power available to the connected heater. The High range provides the
maximum power, the Med range provides (maximum power)/10 and the Low range
provides (maximum power)/100. Refer to
section 2.5.1 for details on how to calculate
the maximum output power. When Output 2 is configured as a voltage output, only
one output range (On) is available.
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 are determined by the heater resistance, Max Cur-
rent setting, and Heater Range.
Specifications of the heater outputs are provided in section 1.3. Heater theory of
operation is provided in section 2.5. Various heater installation considerations are
provided in section 3.7.
To set Heater Range, first configure the front panel display to show the desired control
loop information, then use the Heater Range key on the front panel. A quick way to
access the setting if the control loop information is not already displayed is to use the
front panel A or B keys to temporarily display the control loop information while the
new setting is entered. Refer to
section 4.2 for details on configuring the front panel
display.
Menu Navigation:
Heater RangeQ(Off, On, Low, Med, High)
Default: Off
Interface Command: RANGE
4.5.1.7.9 ALL OFF
The ALL OFF key is provided as a means of shutting down all control outputs with one
key. It is equivalent to setting the Heater Range parameter of both outputs to Off.
This function is always active even if the keypad is locked or when it is in remote mode.
4.5.2 Voltage Output
The voltage output available for Output 2 is a variable DC voltage source that has a
range from –10 V to +10 V. The voltage is generated by a 16-bit D/A converter with
resolution of 0.3 mV or 0.003% of full scale. This output can be configured to Closed
Loop PID, Zone, Open Loop, Warm Up Supply, or Monitor Out modes. The Closed Loop
PID mode can be used to control temperature. It can also be set up for bipolar PID con
-
trol, which is useful when controlling a thermoelectric device. Refer to section 2.11
for more information on setting up thermoelectric devices. The Open Loop mode can
be used to set the output to a specific, constant value. Refer to
section 4.5.1.6.3 for
details on Open Loop Mode. The Warm Up Supply mode uses the output to drive the
programming input for an external power supply for the purpose of rapidly warming
a system to a user-specified temperature. The Monitor Out mode uses the output to
provide a voltage proportional to an input sensor reading to be used by an external
device such as a data logger.