7.4.2
Scan Rate
The next function in the main menu is the scan rate. The scan rate can be set
from .1 to 99.9°C/min. The maximum scan rate however is actually limited by
the natural heating or cooling rate of the instrument. This is often less than
100°C/min, especially when cooling.
The scan rate function appears in the main menu after the scan control function.
The scan rate units are in degrees per minute, degrees C or F depending on the
selected units.
Sr= 10.0
Scan rate in°C/min
Press “UP” or “DOWN” to change the scan rate.
Sr= 2.0
New scan rate
Press “SET” to accept the new scan rate and continue.
S
Accept scan rate
7.5
Set-point Resistance
The set-point resistance is used for calibrating the instrument. See
Section9
.
Pressing “SET” and “DOWN” simultaneously displays this value.
7.6
Secondary Menu
Functions which are used less often are accessed within the secondary menu.
The secondary menu is accessed by pressing “SET” and “EXIT” simulta-
neously and then releasing. The first function in the secondary menu is the
heater power display.
7.7
Heater Power
The temperature controller controls the temperature of the system by pulsing
the heater on and off. The total power being applied to the heater is determined
by the duty cycle or the ratio of heater on time to the pulse cycle time. By
knowing the amount of heating the user can tell if the system is heating up to
the set-point, cooling down, or controlling at a constant temperature. Monitor-
ing the percent heater power lets the user know how stable the temperature is.
With good control stability the percent heating power should not fluctuate more
than
±
1% within one minute.
The heater power display is accessed in the secondary menu. Press “SET” and
“EXIT” simultaneously and release. The heater power will be displayed.
S
+
E
Access heater power in secondary menu
27
7 Controller Operation
Set-point Resistance
