Rockwell Automation 1746-BTM Barrel Temperature Control Module User Manual - Manual (Page 29)

Publication 1746-UM010B-EN-P - April 2001
Configuring the Module 3-3
Barrel/Non-barrel Control Word 1, Bit 12 for Channel 1
You select between barrel and non–barrel control.
Barrel Control
Select barrel control for multiple–zone applications in which there is
thermal conduction between the zones. Injection molding and
extrusion are good example applications because they use multiple
heater bands (zones) mounted on one thermal conductor (the metal
barrel). The barrel conducts heat between different zones. If you
select barrel control, also select between inner and outer zones (word
1, bit 13 for channel 1). A barrel loop is autotuned as the temperature
rises from a cold start to a temperature setpoint during startup.
Non–barrel control
Select non–barrel control for applications with independent loops and
no thermal conduction between zones. If you select non–barrel
control, the inner/outer zone selection doesn’t apply.
Switching the barrel control
For some applications, even though the loops are independent with
no thermal conduction between zones, barrel control might provide
better performance than non–barrel control. If a loop has any of these
characteristics, you might want to use barrel control if the:
•
time constant is greater than 10 - 30 seconds
•
loop has a problem of overshooting the setpoint
•
loop output is saturating (CV is at 100%) for a significant
duration
Select: for these applications: 12
barrel control heat–only or heat/cool 0
non–barrel control heat–only, cool–only, or heat/cool 1