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Low Temp Furnace Model ITL-M-17701 13-07/20
Using the HOLDBACK feature:
The PROGRAMMER has a HOLDBACK feature available.
Holdback pauses the program (freezes the Programmer setpoint (PSP) and the time remaining parameters)
if the difference between the Process value (PV) and the PSP exceeds a user-specified amount (Holdback
value). The program remains paused until the PV returns to within the specified deviation.
In ramp or step segments, holdback indicates that the PV is lagging the SP by more than the specified
amount and that the program is waiting for the process to catch up. In a dwell segment, holdback is used
to guarantee that a work piece stays at set-point within a specified tolerance for the specified dwell
duration.
Figure 13
This is particularly useful when running a calibration program as it will allow the heat source to eliminate
any “lag” between the controller and the heat source itself.
Holdback can be configured to hold either the segment or the complete program.
The USER defined value is used to define the actual value applied to it.
This can either be:
LOW, where the heat source temperature is below the Setpoint. The programmer will hold the value until
the heat source has “caught-up” in temperature.
HIGH, where the heat source temperature is above the Setpoint. The programmer will hold the value until
the heat source has “caught-up” in temperature.
BAND, where the heat source is outside a band of temperature around the setpoint
To enable this feature:
1. Go to EDIT AN EXISTING PROGRAM and enter the menu
2. Scroll to HOLDBACK STYLE and enter using the SCROLL button
3. Select desired parameter and enter using the SCROLL button
4. Scroll to CH1 HOLDBACK and enter the desired parameter and enter with the SCROLL button
5. Scroll to CH1 HOLDBACK VAL and select the desired temperature, enter using the SCROLL button
