CONTREX MLP-Trim - Manual (Page 73)

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Follower Mode Analog Feedback Example
The following example demonstrates Follower mode scaling using analog feedback:
A pump delivers 20.0 gallons per minute of ingredient A when the pump
motor rotates at 1800 RPM. A second pump delivers 10.0 gallons per
minute of ingredient B when the pump motor rotates at 1800 RPM. A
tachometer connected to the analog input of the MLP-Trim produces a
10.0 volt signal when the pump B (follower) motor rotates at 1800 RPM.
The lead motor A has an encoder feedback of 1000 PPR. The Follower
setpoint is to reflect the flow ratio in gallons/minute of ingredient B to
ingredient A.
Table 3-24 Follower Mode Feedback Allocation Example
CP Parameter Name Value Remarks
CP-84 Analog Input
Allocation
CP-21 Follower
Engineering Units
CP-33 Max RPM Lead
CP-30 PPR Lead
Allocates the analog input as the
feedback source.
This is the Engineering Unit value
that is present if the analog input
were at 10.0 volts and the lead at
Max RPM Lead.
10.0 gal/min (ingredient B) = 0.500
20.0 gal/min (ingredient A)
The maximum operating RPM of
the lead shaft.
The resolution of the lead
sensor.
2
0.500
1800
1000