User guide

Watlow EZ-ZONE
®
PM PID Controller • 98 • Chapter 9 Features
Variable Time Base (cont.)
The combination of variable time base output and a solid-state relay can inexpensively approach the effect
of analog, phase-angle fired control.
Select the AC Line Frequency [AC;LF] (Setup Page, Global Menu), 50 or 60 Hz.
Note:
When output 1 is a universal process output, output 2 cannot use variable time base, fixed time base only.
Single Set Point Ramping
Ramping protects materials and systems that cannot tolerate rapid temperature changes. The value of the
ramp rate is the maximum degrees per minute or hour that the system temperature can change.
Select Ramp Action [``rP] (Setup Page, Loop Menu):
[`oFF] ramping not active.
[`Str] ramp at startup.
[StPt] ramp at a set point change.
[both] ramp at startup or when the set point changes.
Select whether the rate is in degrees per minute or degrees per hour with Ramp Scale [`r;SC]. Set the
ramping rate with Ramp Rate [`r;rt] (Setup Page, Loop Menu).
100 percent output
10 ON, 0 OFF
50 percent output
3 ON, 3 OFF
66 percent output
6 ON, 3 OFF
Set Point
Time
Temperature
Heating System without Ramping
Temperature reaches Set Point quickly
Set Point
Time
Temperature
Temperature ramps to Set Point at a set rate
degrees
per minute
Heating System with Ramping