CONTREX MLP-Trim - Manual (Page 70)

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Follower Mode Analog Lead Example
The following example demonstrates Follower mode scaling using analog lead:
A pump delivers 20.0 gallons per minute of ingredient A when the pump
motor rotates at 1800 RPM. A second pump delivers 40.0 gallons per
minute of ingredient B when the pump motor rotates at 1800 RPM. A
potentiometer connected to the analog input of the MLP-Trim produces
a 10.0 volt signal when the pump A (lead) motor rotates at 1800 RPM.
The following motor B has an encoder feedback of 30 PPR. The Fol-
lower setpoint is to reflect the flow ratio in gallons/minute of ingredient B
to ingredient A.
Table 3-21 Follower Mode Lead Allocation Example
CP Parameter Name Value Remarks
CP-84 Analog Input
Allocation
CP-21 Follower
Engineering Units
CP-34 Max RPM Feedback
CP-31 PPR Feedback
Allocates The analog input as the
lead source.
This is the Engineering Unit value
that would be present if the analog
input were at 10.0 volts and the
feedback at Max RPM Feedback.
40.0 gal/min (ingredient B) = 2.000
20.0 gal/min (ingredient A)
The maximum operating RPM of
the feedback shaft.
The resolution of the feedback
sensor.
1
2.000
1800
30