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MUST HAVE. SHOULD HAVE. COULD HAVE. Module # 050. Batch Control Software. PAM & CPM Services. FBM. Fieldbus. Ethernet TCP/IP. 1. Measurement Devices Scales & Flowmeters. Overlapping Feeds. Objectives: Know the theory behind overlapping feeds
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MUST HAVE SHOULD HAVE COULD HAVE Module # 050
Batch Control Software PAM & CPM Services FBM Fieldbus Ethernet TCP/IP 1 Measurement Devices Scales & Flowmeters
Overlapping Feeds • Objectives: • Know the theory behind overlapping feeds • Be aware that Crosschecking exists
Overlapping Feeds • Q.i allows, and controls the addition of multiple feeds into a single Scale. • The Rules: • Only one Material can be the Primary • The rest MUST be Flowmeter based OR • Discharge from upstream Scales • The Scale based Material (MP1) must be the last material feeding • Qi will automatically compensate for the amount added via the Flowmeters Secondary’s Primary MP1 Water MP2 Acid MP3 Col Feed Alone time Drain Time FM FM Actual Feed MP3 MP2 MP1 Scale
What if Flowmeter feeds are longer than the Scale based Feed? • The Scale based feed is automatically delayed ! • NOTE: The Qi aims for the FeedAloneTime + Tolerance, but will accept FeedAloneTime • The Tolerance will allow process variations to vary without failing the overlapping feeds rules (within reason) Drain Time Feed Alone time Actual Feed MP3 Secondary Feeds MP2 MP1 Primary Feed Qi automatically delays start of feed
Actual calculations are as follows: • With no Flow rate variations the actual Feed Alone Time will be the Feed Alone Time + Feed Alone Tolerance Feed Alone time Feed Alone Tolerance Drain Time Actual Feed MP3 Secondary Feeds MP2 MP1 Primary Feed Qi automatically delays start of feed Cutting OFF anywhere here is OK!
Crosschecking • Qi Matroller can “Crosscheck” the accuracy of Flow meters against a Scale • Qi must be instructed to “Crosscheck” with a Special command (15) • Command structure is similar to an Overlapping Feed command structure • Instrument Crosschecking is NOT an automatic feature
Review Questions • How many Primary (Scale based feeds) are there in an Overlapping Feed group? • How many Secondary’s can there be? • Bonus Question • What is the purpose of the Overlapping Feed Tolerance parameter?