Holdback consists of a value and a type. If the measured value lags behind
the setpoint by an undesirable amount during a ramp or dwell, the
holdback feature can be used to freeze the program at its current state (the
HOLD light will flash). The program will resume when the error comes
within the holdback value.
OFF:
holdback is disabled.
Lo (Deviation Low Holdback)
: holds the program back when process
variable deviates below the setpoint by more than the holdback value.
Hi (Deviation High Holdback)
: holds the program back when process
variable deviates above the setpoint by more than the holdback value.
bAnd (Deviation Band Holdback)
: combines the features of the high and
low deviation holdback in that it holds the program back when the process
variable deviates above or below the setpoint by more than the holdback
value.
To set the holdback type:
1. Press the PAGE button until you reach the program list (ProG LiSt).
2. Press the SCROLL button until display reads, “Hb.”
3. Press the UP or DOWN button to toggle between “bAnd, Hi, Lo and
OFF.”
Hb U: Holdback Value
Note
The value set in this parameter is always for the entire program.
▲
To set the holdback value:
1. Press the PAGE button until you reach the program list (ProG LiSt).
2. Press the SCROLL button until display reads, “Hb.U.”
3. Press the UP or DOWN button to enter a holdback value.
6-8
Clean Room Oven
Thermo Scientific
Section 6
Programmable Models
Hb: Holdback