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BECKHOFF BK3xx0 User Manual

Page 38

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Notes on the Documentation

36

Fieldbus Components

DP buffer

Default

Maximum size

Inputs

128

244

Outputs

128

244

Diagnostic Data

64

64

Configuration data

64

244

The sizes can be adjusted through the PrmData. The length is modified in steps of 8 bytes.

Example:
If it is desired to increase the size of the input data, other sizes must be reduced to compensate.
If we have 20 x 4 channel KL3314 thermocouples, then in compact mapping we find 20 Bus Terminals * 4 channels *
2 bytes per channel = 20 * 4 * 2 = 160 bytes
160 bytes is larger than the 128 byte default figure - settings must therefore be modified.
Set PrmData byte 12 bits 4-7 to 15 dec or 0xF hex, set byte for 37 to 160 (input data) and byte 38 to 96 (output data).