Industrial Data Systems IDS Scale Basic - Manual (Page 9)

Scale Basic 4.2E Tutorial
Sequence of operation
Enter target weight data: Use the indicator’s built in memory register input function.
The operator sets memory registers 1, 2, and 3 for container 1, 2, and 3.
Select a target weight. Use the F1 key to initiate target weight selection. The display prompts
“Con”. The operator enters the container number that will be filled.
Monitor weight for over/under:
use Power On Start to initiate underweight scan by activating user function1.
Function 1 turns on Setpoint Monitor 1, and turns Under-weight light (relay 1).
Setpoint 1 triggers when the scale is no longer under weight. It activates function 2.
Function2 turns on Setpoint Monitor 2 (overweight scan) and turns on relay2, and turns
off relay 1.
Setpoint 2 triggers when the scale is no longer over weight. It activates function 1.
REVIEW:
It is unlikely that the operator can fill to the exact target weight. (neither over or under).
After consulting with the customer, it is determined that the fill tolerance should be within 2% of
the target weight.
MODIFIED DESIGN:
Application Description
The operator places containers on the scale and fills them with resin. An ‘Under-weight’ light
turns on while the container weight is more than 2% below the target weight. There are 3 sizes
of container, each is filled with a different amount of resin. If the container is filled with too
much resin (more than 2% over target weight), turn on an ‘Overweight’ light until enough
resin is removed for the container to be within specifications.
Sequence of operation
Enter target weight data: Use the indicator’s built in memory register input function. The
operator sets memory registers 1, 2, and 3 for container 1, 2, and 3.
Select a target weight. Use the F1 key to initiate target weight selection. The display prompts
“Con”. The operator enters the container number that will be filled. The over weight setpoint
and underweight setpoints are calculated by adding/subtracting 2% from the target
weight.
COMMENTS:
The changes to the design are shown above in bold lettering.
Notice how each step in the program design is a refinement of the previous step.
Also note that often, missing specifications and other problems don’t become apparent until well
into the design process. Many times the approach will have to be changed.