CHAPTER 4: OPERATING INSTRUCTIONS
UNIFLOW
®
4 PULSED HEAT CONTROL
4-8 990-908
The Control begins to ramp the temperature during the RISE1 period at the ramp rate you set.
As soon as the temperature in Rise1 reaches 140° C, Rise1 will end and Preheat will start. The
Control will immediately control temperature to the Preheat temperature and there could be a
fast rise to Preheat temperature. The temperature increase may not follow the programmed
RISE1 ramp rate after the Temperature delta is reached. Rise2 and Reflow will perform in a
similar manner.
As for the display on the
DATA screen, if the time from the start of Rise1 to 140° C is 1.7
seconds, then 1.7 seconds will display for the time of
Rise1. The length of Preheat will be 3.0
seconds and the total time of Rise1 + Preheat will be 4.7 seconds.
Functionality Example #2: Time is selected for Preheat and Reflow Control. This is based on
the following Control settings:
Temperature delta for preheat = 10° C
Rise1 time of 2.0 seconds
Preheat time of 3 seconds
Preheat temperature of 150°C
With these settings the Control ramps the temperature during the entire RISE1 period at the ramp
rate you set, and it switches control to the Preheat temperature at the end of the full RISE1 time.
As for the display on the DATA screen, if the time from the start of Rise1 to 140° C is 1.7
seconds, then 1.7 seconds will display for the time of Rise1. The length of Preheat will be 3.3
seconds, so the total time of Rise1 + Preheat will be 5 seconds.
If you select Temperature for the Preheat and Reflow Control, and set Rise1 and Rise2 to zero
seconds, the Control will behave as shown below. (If you set Rise1 or Rise2 to zero, the DATA
screen will display zero seconds for these periods.)
Functionality Example #3: Temperature is selected for Preheat and Reflow Control. This is
based on the following Control settings:
Temperature delta for preheat = 10° C
Rise1 time of 0.0 seconds
Preheat time of 1 seconds
Preheat temperature of 150°C
Rise2 time of 0.0 seconds
Reflow time of 1 seconds
Reflow temperature of 300°C
The Control will perform as shown in the following diagram. The slope of the temperature
increase will be based on the
Coarse and Fine Heating Rates as well as the PID Control settings.
The times reported on the
DATA screen will be as follows:
Rise1 time of 0.0 seconds
Preheat time of 1.2 seconds
Rise2 time of 0.0 seconds
Reflow time of 1.3 seconds
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