Sterlco GH-M Series Extrusion Control Weigh Hoppers - Manual (Page 59)

Chapter 7: Appendix 59 of 60
WRITING SETPOINTS EXPLANATION
Extruder RPM set points, recipe set points, and haul-off set points can be wrote to while the unit is in stop
mode. After engaging either RPM mode or Weight mode then the appropriate values will be applied.
While in RPM mode the target recipe value will be overwrote by what the current actual running value is.
This ensures that when you transfer to “Weight Mode” that the line set points do not change. This acts as
a virtual cruise control for your line. Bring the extruder and haul-off up to the desired outputs and then
place the unit in “Weight Mode” to maintain the ratio even as the screen pack builds up material over
time.
The Extruder RPM set points and haul-off set points can be modified while in RPM mode and the unit
will respond immediately.
The Recipe set point can be modified while in Weight mode. Some recipe set points may include the
extruder RPM or the haul-off speed depending on the recipe mode selection. If the recipe mode selection
is lbs/ft and the second entry is set to extruder rpm input then the target lbs/ft and the extruder rpm is set
by the operator while the PLC calculates the target feet/min needed to achieve the desired recipe.
No set points can be modified while in “Monitor Mode”. The PLC will take constant snap shots of the
extruder RPM, haul-off speed, and recipe set points and will write these to ensure a “bump-less” transfer
when entering into either RPM Mode or Weight Mode.
The system can be placed in “RPM Mode”, or “Monitor Mode” from stop at any time. The system can go
from “RPM Mode”, “Weight Mode”, or “Monitor Mode” into stop mode at any time as well. However,
there are restrictions when transferring between other modes. The system must be stable before it will
allow you to transfer from “RPM Mode” into “Weight Mode”. Also the system must be stable when
transferring from “Monitor Mode” to “RPM Mode”. If you are in “Monitor Mode” you must transfer into
“RPM Mode” and then stabilize before going into “Weight Mode”.
FIXED DECIMAL EXPLANATION
All weight values and recipe values use fixed decimal. This must be taken into consideration when
writing or reading values. If you see “xxx.xxx” above this means the data is in fixed decimal and must be
scaled when reading or writing. A decimal is shown next to each item to represent the format.