Rockwell-automation 1734-IK Encoder/Counter Modules User Manual Manuel d'utilisateur télécharger pdf (Page 36)

Publication 1734-UM006B-EN-P - August 2005

3-4 Input and Output Data

Zero frequency Detected (ZD) - This bit is operational when

frequency configurations are programmed (configurations: period/rate

[5], rate measurement [7]).

In period/rate [5] configuration, counts are acquired during

the ON state of the Z input. At very low frequencies the counter

saturates, indicating a zero frequency detect. The time it takes to

determine a zero frequency in these two configurations can be

as long as 6.7 seconds ( 16,777,216 counts x 1/5MHz x 2 half

cycles of Z ).

In rate measurement [7] configuration pulses on the A input

are counted over a sample interval specified by the time base.

The time it takes to determine a zero frequency in this

configuration will be determined by the sample interval, for

example, time base = 0.300 second (300 milliseconds) to

determine ZF.

Configuration Data

The following represents the configuration data used by the module.

Parameter Configuration Information Size (bytes)

1 Set/Get Counter Configuration 1

2 Set/Get Filter Selection 1

3 Set/Get Decimal Position 1

4 Set/Get Reserved 1

5 Set/Get Time Base 2

6 Set/Get Gate Interval 1

7 Set/Get Scalar 1

8 Set/Get Rollover Value 4

9 Set/Get Preset Value 4

10 Set/Get Counter Control SS Value 1

1 2 ... 31 32 33 34 35 36 37 38 39 40 41 ... 67 68

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Rockwell-automation 1734-IK Encoder/Counter Modules User Manual Manuel d'utilisateur Page 36