9
TDD
FM Rev. 8/6/01
5.2.4 duo - Window Point
This menu item allows the user to set a value above the switchpoint such that a
temperature band, or window can be monitored.
Note: The duo value must be a positive number and it must be a larger value that the
SPo value. If it is not, an error message is displayed. If the error occurs both the
SPo value and the duo values are cleared and must be re-entered.
Additionally, a decimal point can be added if desired. Section 5.1.1 ‘Changing Values in
Setup Mode’ on page 6 provides steps required to change a value. When the measured
temperature is above the switchpoint, the switch will activate. The switch will de-activate
when the measured Temperature either increases to above the window point value or
decreases to below the switchpoint value. The window point can also used with the
hysteresis function if desired.
Example: Switchpoint
Value
(SPo) is set at 50
Window Point (duo) value is set at 75
Hysteresis Value (HYS) is set at -5
The switch will activate (LED on) when measured Temperature is above
50.0 and will de-activate (LED off) when measured Temperature is above 80
(75 + 5) or below 45 (50 - 5).
5.2.5 Filt - Filtering
This menu item allows the user to average the measured output over 1, 2, 4, 8, 16, 32 or
64 samples. Section 5.1.1 ‘Changing Values in Setup Mode’ on page 6 provides steps
required to change a value. Adding filtering provides a more stable display and prevents
false switching for systems in which spurious temperature fluctuations are a problem. The
larger the number of samples the more stable the display and switch. A Filt value of “1”
shuts off the filtering.
When filtering is being used, the TDD series employs an integrated overshoot function
which detects any overshoot above 6.25% and processes that measured value without
filtering. This feature allows the switch to differentiate between spurious fluctuations and
Temperature
Switch
On
Off
Temperature
Switch
On
Off
Case 1: Switch set as
Case 2: Switch set as
Normally Open
Normally Closed
45
50
75
80
45
50
75
80
