Wet Dog Glass
Temperature controllers are the component you will most often use on your equipment. Watlow controllers are what we primarily use, and what you will see most often on glass equipment. These are called PID controllers. They look at the temperature you want to get to, called setpoint, and the temperature the equipment is currently at, called process value, and figures out the most efficient way to do that. If you’re only a few degrees low, you don’t want the burner to blast to 100%.
While these controller have many settings in them that the average user will never need to adjust, here are a few that will help you understand what it’s doing, and that you may want to change depending on your use.
There are several important things to understand before starting on writing profiles.
•Watlow PM controllers have 40 possible “steps” split into 4 profiles of 10 steps each
•Profile 1 uses steps 1-10, profile 2 uses steps 11-20, profile 3 is steps 21-30, profile 4 is steps 31-40.
•Always attend a piece of equipment when running a profile for the first time or after changes, to be sure it is doing what you want.
While profiles can become very complicated, 3 kinds of steps are primarily used; Soak, Time and End. All steps default to unused (UStP) and should be set to this when not wanted.
Soak (SoAh) holds the current set point for the amount of time you specify before moving onto the next step
Time (ti) moves the set point from its current value to the temperature you specify over the amount of time you specify.
End ends the profile, and allows you to choose what happens to the set point once the profile is over.
Use the chart in the example profile to plan your profile, and refer to it as you enter the profile into the controller. The profile shown is the basic annealer profile preload onto oven controllers.
Entering a Profile into the controller
Begin by holding the green button until you see P1 on top and ProF on bottom. The arrow keys will cycle you through P1-P4. Select the profile to be edited, and press the green button
You’ll now see 1 on top and P1(or P2,3,4) on bottom. The top number is the step selected. Use the arrows to select the step to be edited and press the green button.
This is the final menu level where settings are changed. The green button cycles through the available settings on the bottom screen, and the arrows change the setting on the top screen. Using the example profile, the display after selecting P1, and Step 1 should be S.tYP on bottom, and SoAh on top. The arrows change the step type, and the green button advances to the next option. When all the parameters of the step are set, press the reset button to return to the step selection screen.
It often helps when writing a new profile to set all steps for 10 seconds, so the profile can be run and tested to make sure it is working properly, then change the times to the correct amounts.
Starting, ending, and pausing a Profile
From the main screen, press the advance key (green) until P.St 1 (Profile Start) appears on bottom and a number on top. The number on top is the profile or step to be started, pasued, or ended.
Press the advance key to move on to P.AC 1 (Profile Action). Select ProF on the top screen to start profile 1-4. Select StEP to start at step 1-40. PAUS will pause the currently running profile at its current step and set point, rESU resumes it. End ends the currently running profile. When the action has been selected on the top screen, press reset to return to the home screen. A graph icon on the right side of the screen indicates a profile is running.
When a profile is running, the current step type, and time remaining (CSP, S.tYP, hour, min, sec), can be seen by cycling through the home screen with the green key, only on controllers in 2019 equipment and newer.
This is a basic annealing profile that comes as the default for profile 1 in our annealing and casting ovens. We suggest adjusting the times and temperature to fit your glass and work.
Step 1 takes the set point to 900 in one second, so that the oven gets back to annealing temp after losing some heaT from opening the doors to put the last piece of glass in.
Step 2 soaks at that 900 set point for 3 hours.
Step 3 goes from 900 to 800 over 3 hours
Step 4 goes from 800 to 690 over 3 hours
Step 5 goes to room temp over 2 hours (Usually the profile outpaces the ovens cooling during this step, and the oven cools naturally)
Step 6 ends the profile and leaves the set point at 70.
The control mode is something you may never change on an electric oven, but is often used when tuning combustion equipment. When in auto you tell the controller the set point, and it decides what % to be at to get there or maintain that temperature. When in manual you set that % directly. For tuning this keeps the blower at the same speed, which lets you adjust the gas to be a good neutral flame.
The other option in this setting is Off, which will stop the controller entirely. On electric equipment this is the same as 0%, but on combustion equipment this will turn the blower off entirely (0% for a blower is still on, just barely).
Changing Control ModeDepending on the generation of controller you have, this will appear in two different formats.
2019 and Newer EquipmentOn combustion equipment, press the green advance key once and you will see the current heat percentage on top and the current control mode on bottom. On electric equipment, press the green advance key several times until you see the same screen.Use the arrows keys to cycle between “AUto”, “Man”, “oFF”. Once selected, hit the reset(infinity) key to go back to the main screen. This will show either a temperature (auto) a percent (manual) or off in the bottom and the current temperature on top.
2019 and Older EquipmentOn combustion and electrical equipment, press the green advance key several times until you see the current control mode on top and C.M1 on bottom. Use the arrows keys to cycle between “AUto”, “Man”, “oFF”.Once selected, hit the reset(infinity) key to go back to the main screen. This will show either a temperature (auto) a percent (manual) or off in the bottom and the current temperature on top
Proportional BandThis is the setting that decides how big of a range the controller ramp powers in when not at 0% or 100%. For example, with a proportional band of 50 degrees whenever the process value is more than 50 degrees from set point the controller will be at 0% or 100%. When within 50 it will begin ramping up(or down) so that it does not overshoot the setpoint. With too small a proportional band your equipment will bounce around too much as it tries to maintain the setpoint. When too large, the equipment will be slow to go up or down because it doesn’t stay at 0% or 100% for long enough.