Baumer BMSH 58 Manual - Página 22

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6.4. Input and output data

Module "Encoder data 32 Bit IO" is utilized for cyclic transmission of 4 byte encoder input data and 4 byte

encoder output data.

Input data (position value)

Encoder input data transmission to the control is performed cyclic by a consistent 32-bit, right-aligned data

word in binary code. To read the position the PLC software should access the parameterized input data

address using a double word.

Position

Output data (preset value)

There is cyclic and consistent output data transmission from control to encoder. The output data may serve to

set the encoder to a defined position value within the parameterized total sensing range.

Preset

Bit 31:

Preset

6.5. Preset function

The preset function in the encoder is triggered by the PLC using bit 31 which is set in the output data. The

encoder position is set to the preset value (bit 30...0). Bit 31 should remain set for at least 10ms to be

recognized by the encoder. Afterwards time by principle does not matter since only a change in bit status

from „0" to „1" will be evaluated. We recommend however to clear the bit after completion in order to provide

the original status for the next preset operation.

For optimum alignment of mechanical position to preset we recommend to set the preset value during

encoder standstill, but it may also do during encoder operation for inferior requirements.

It is mandatory to parameterize the required resolution or code sequence (cw/ccw) prior to performing the

preset operation.

Upon performing a preset operation an internal offset is calculated and stored non-volatile in the Flash

memory to make sure the encoder will be at the same position again after power-off and power on. Although

the Flash provides 100.000 writing cycles, frequent software or event-triggered setting operations may

consume even this capacity what has to be considered in the control software configuration.

Note:

Any alteration of the total measuring range during encoder re-parameterization will implicate clearing the

internal preset-offset value. This however has no effect in practice since in this case the position is lost

anyway.

Manual_PROFINET_EN.doc

17.10.11

Encoder position (right-aligned)

Preset (right-aligned). Preset operation is started by bit31

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