Emerson 3402 - Position Scaling Denominator; Maximum Reference Frequency; Frequency Reference Scaling; Frequency Reference

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60 Commander SK Advanced User Guide
www.controltechniques.com Issue Number: 9
Pr 3.33 and Pr 3.44 are used to scale the pulse counter down to the required position units. The multiplying factor applied to the counter is defined as:
The table below shows how the resolution decreases as the maximum reference frequency decreases:
Example:
With Pr 3.43 set to 10kHz and the destination parameter (Pr 8.25) set to preset speed 1 (Pr 1.21).
When the input frequency on terminal B7 is 10kHz, preset speed 1 will be 50Hz (Pr 1.06 = 50Hz, Eur defaults). This will have a resolution of 11 bits.
Frequency input with High Resolution
When Pr 8.35 is set to 3 (Frequency input with high resolution) this gives a 12 bit input for maximum reference frequencies of 12kHz and greater.
Pr 1.19 is automatically updated with the 2 LSBs.
Example:
With a maximum reference frequency of 12kHz, the resolution is 12 bits.
With a maximum reference frequency of 2kHz, the resolution is 9 bits.
Scale factor applied to the frequency reference.
Indicates the percentage of the frequency input value, up to the maximum reference frequency (Pr 3.43).
3.34 Position scaling denominator
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
1 111
Range 0.0 to 100.0
Default 1.0
Update rate Background
3.35 to 3.42 Unused parameters
3.43 Maximum reference frequency
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
1 111
Range 0.0 to 50.0 kHz
Default 10.0
Update rate Background
Maximum reference frequency Resolution
6kHz – 50kHz 11 bits
3kHz – 6kHz 10 bits
1.5kHz – 3kHz 9 bits
750Hz – 1.5kHz 8 bits
375Hz – 750Hz 7 bits
3.44 Frequency reference scaling
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
3 111
Range 0.000 to 4.000
Default 1.000
Update rate Background
3.45 Frequency reference
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
11 1 1 1
Range 0.0 to 100.0%
Update rate 5 ms
Pr3.33
Pr3.34
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