4.5.2 Encoder input frequency

The maximum encoder input frequency is affected by the length of the encoder cables. The theoretical maximum frequency is 7.5 million quadrature counts per second. This is equivalent to a maximum frequency for the A and B signals of 1.87MHz. However, the effect of cable length is shown in Table 3:

Frequency

 

Maximum cable length

meters

 

feet

 

 

 

 

 

 

1.3MHz

2

 

6.56

 

 

 

 

500kHz

10

 

32.8

 

 

 

 

250kHz

20

 

65.6

 

 

 

 

100kHz

50

 

164.0

 

 

 

 

50kHz

100

 

328.1

20kHz

300

 

984.2

 

 

 

 

10kHz

700

 

2296.6

 

 

 

 

7kHz

1000

 

3280.8

Table 3 - Effect of cable length on maximum encoder frequency

The maximum recommended cable length is 30.5m (100ft).

4-16 Input / Output

MN1903

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Baldor MN1903 installation manual Encoder input frequency