Emerson Vilter Vission 20/20, Operation And Service Manual

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B - 11
Appendix B • Vission 20/20 Application Procedures
Vission 20/20 • Operation and Service Manual • Emerson • 35391SC 2.7
Scenario 11:
Suction Pressure = 54 Psig
Calc VR= 2.0
Volume = 0%
Capacity = 100% (4850mV)
Scenario 3:
Adjust Suction Pressure = 28 Psig
Calc VR= 3.0
Capacity = 100% (4145mV)
Low VI Digital Output = OFF
High VI Digital Output = ON
Scenario 4:
Adjust Suction Pressure = 12 Psig
Calc VR= 4.3
Capacity = 100% (4145mV)
Low VI Digital Output = OFF
High VI Digital Output = ON
Scenario 5:
Adjust Suction Pressure = 11 Psig
Calc VR= 4.4
Capacity = 100% (3440mV)
Low VI Digital Output = OFF
High VI Digital Output = OFF
Scenario 6:
Adjust Suction Pressure = 7 Psig
Calc VR= 5.0
Capacity = 100% (3440mV)
Low VI Digital Output = OFF
High VI Digital Output = OFF
Scenario 7:
Adjust Suction Pressure = 13 Psig
Calc VR= 4.2
Capacity = 100% (3440mV)
Low VI Digital Output = OFF
High VI Digital Output = OFF
Scenario 8:
Adjust Suction Pressure = 14 Psig
Calc VR= 4.1
Low VI Digital Output = OFF
High VI Digital Output = ON
Capacity = 100% (4145mV)
STEP VI EXAMPLE
Setup:
Compressor - VRS
Refrigerent – R717
Suction Pressure Control Setpoint = 2 psig
VI Control Method - Step VI
Time Interval = 20 sec
Step 1 = 2.2
Step 2 = 3.5
Step 3 = 5.0
Capacity Min Limit = 150mV
Capacity Step 3 Max Limit = 3440mV
Capacity Step 2 Max Limit = 4145mV
Capacity Step 1 Max Limit = 4850mV
In this example the average of Step 1 and Step 2 will be
2.85 and the average of Step 2 and Step 3 will be 4.25. So
the VI values from 2.2 to 2.85 will be considered as Step
1 VI, from 2.86 to 4.25 as Step 2 and more than 4.25
will be considered as Step 3. The step for step VI will not
change till the VI value does not go beyond the average
of two steps. There is hysteresis of 0.1.
Start Compressor in Auto Run Mode.
Discharge Pressure = 160 Psig
Scenario 1:
Adjust Suction Pressure = 54 Psig
Calc VR= 2.0
Capacity = 100% (4850mV)
Low VI Digital Output = ON
High VI Digital Output = OFF
Scenario 2:
Adjust Suction Pressure = 29 Psig
Calc VR= 2.9
Capacity = 100% (4850mV)
Low VI Digital Output = ON
High VI Digital Output = OFF