47
C4 Manual Rev 7.5.2
Program step.substep Data Effect/Purpose
05.0 78.0 Sets temp setpoint to 78°
05.1 00.20 Sets ramp time to 20 minutes
05.2 00.20 Sets hold time to 20 minutes
05.3 6 Sets step 6 as next step to execute
05.4 1 Selects probe 1 for active control
6.1.2 Maximizing Ramp Speed & Other Ramp Considerations
When a ramp time is specified in a program step, the controller attempts, within
the limits of system capability, to achieve a linear temperature change rate such
that the setpoint is achieved precisely at the end of the ramp period. If an
insufficient ramp time is specified, some of the hold time will be “borrowed” to
allow the ramp to setpoint to complete.
To achieve the maximum ramp rate, set the ramp time (substep 1) to 00.00 and
the hold time (substep 2) to 99.00. A program step with a ramp time of 00.00 and
a hold time (substep 2) of 99.00 will cause the controller to achieve the setpoint as
quickly as possible then immediately execute the next step. If a specific hold time
following ramping at maximum ramp rate is required, then use two steps. Both
steps should specify the same setpoint. The first step should have a ramp time of
00.00 and a hold time of 99.00. The second step should have a ramp time of 00.00
and the desired hold time.
Note & Warning: A program step with specified ramp and hold times will
terminate at the end of the specified time (ramp time + hold time), regardless of
whether the controller was able to achieve the setpoint. On the other hand, a
maximum speed ramp step (substep 1 = 00.00 & substep 2 = 99.00) will not
advance to the next step until and unless the setpoint is achieved. If the unit
under test generates or absorbs heat in a manner that prevents the test
environment from ever becoming stable at the setpoint, the program will “hang”
on such a step as it will not advance to the next step unless it can stabilize the
platform or chamber at the setpoint.
A program step with a ramp time of 00.00, a hold time of 00.00, and a probe
number of either 1 or 2 is a null program step. A null program step has no effect
on the temperature setpoint of the chamber. It is used to fill an unneeded step in
an existing program.
