Loops
The current process variable is displayed at the top, with each loop set point displayed beneath the process variable. The operator can change the process set point by touching the screen area below the large process variable numbers. When pressing the Temperature or % Carbon set point a numeric keypad is displayed, showing the current value and allowing you to enter a new set point by simply pressing on the appropriate numeric keys. Once the correct set point has been entered, press the OK key to make the change. When the OK key is pressed the display returns to the Loops Screen.
Also displayed are the probe millivolts, the probe temperature, and the CO Factor. The CO Factor can also be adjusted from this screen. After pushing the COF button a numeric screen pad pops up and allows the authorized personnel to make the appropriate change.
COF is the sole adjustable variable that can be used to influence the calculated carbon potential; with other parameters (Probe mV and Temperature) being fixed. As such COF can be increased/decreased to compensate for differences with a furnace, atmosphere composition, etc. The table below shows how changes to COF will result in different calculated carbon potentials.
Note: Default COF is set to 200.
|
COF |
Prove mV |
Probe Temp |
Carbon |
|
190 |
1100 mV |
1700°F |
0.44 |
|
200 |
1100 mV |
1700°F |
0.46 |
|
210 |
1100 mV |
1700°F |
0.48 |
This example assumes a controller atmosphere set point of 0.46%c. By decreasing the COF to 190, the calculated carbon potential is lowered from 0.46- to 0.44%c. As such the furnace's control system will respond by increasing the volume of enrichment gas to return the atmosphere to equilibrium of 0.46%c. Contrary by increasing the COF to 210, the calculated carbon potential is increased from 0.46- to 0.48%c. As such the furnace's control system will respond by increasing the volume of dilution air to return the atmosphere to equilibrium of 0.46%c.
The Loops Screen also allows you to move back to the Status Screen or to the Recipe Screen by pressing the Recipe button to view the program currently running on the Series 9010 controller.