CONTREX ML-Drive - Manual (Page 53)

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Example B demonstrates how scaling and setpoint Control Parameters are entered for
a typical Follower mode of operation that uses a percentage setpoint:
The Lead pump delivers 20 gallons/minute of ingredient A. The Lead
motor's is running at a maximum RPM of 1800 and the Lead sensor
shaft is equipped with a 60 tooth ring kit. The Follower pump delivers
10 gallons/minute of ingredient B. The Follower motor is running at a
maximum RPM of 1800 and the Follower sensor shaft is equipped with
a 60 tooth Ring kit. Follower Setpoint 1 will be set so that when the
Lead pump delivers 20 gallons/minute of ingredient A, the Follower will
deliver 10 gallons/minute of ingredient B. Setpoint 2 will be set so when
the Lead pump delivers 10 gallons/minute of ingredient A, the Follower
pump will delivers 7 gallons/minute of ingredient B.
Table 3-12 shows the Control Parameters that would be entered in the ML-Drive for
Example B.
To find the ratio for the Follower Engineering Units (CP-21) for Example B:
Follower E.U. at Max Follower RPM 10
Follower E.U. (CP-21) = __________________________________________________ = ___ X 100(%) = 50
Lead E.U. at Max Lead RPM 20
10 gal/min The Follower Engineering Units when the Follower is operating
at maximum RPM
Divided by
20 gal/min The Lead Engineering Units when the Lead is operating at
maximum RPM
Multiplied by 100 (%) equals
50 Follower Engineering Units (CP-21) as a percent of Follower to
Lead.