BECKHOFF BK3xx0 - Manual (Page 82)

Notes on the Documentation
80 Fieldbus Components
Changing the Size of the Process Data
Exceeding the input data length (InputData)
By default, a maximum of 128 bytes of input data is set on the Bus Coupler.
The maximum length of the DP buffer can be changed. The amount, however, by which one length is increased must
be taken away from another, and it must be noted that the sizes can only be changed in 8-byte steps:
Exceeding the output data length (OutputData)
By default, a maximum of 128 bytes of output data is set on the Bus Coupler.
The maximum length of the DP buffer can be changed. The amount, however, by which one length is increased must
be taken away from another, and it must be noted that the sizes can only be changed in 8-byte steps:
Exceeding the configuration data length (CfgData)
By default, a maximum of 64 bytes of configuration data is set on the Bus Coupler. Normally, this is only a problem in
very rare cases. In multi-configuration mode, however, this limit is reached with no more than a 30 digital terminals,
because each KLxxxx MultiCfgMode module occupies two bytes in the configuration data, on top of which there is at
least one sum byte for digital inputs or for digital outputs.
The maximum length of the DP buffer can be changed. The amount, however, by which one length is increased must
be taken away from another, and it must be noted that the sizes can only be changed in 8-byte steps:
Maximum DP buffer sizes
DP buffer Maximum sizes under default settings
Inputs 128 bytes
Outputs 128 bytes
Diagnostic data 64 bytes
Configuration data 64 bytes
Setting via the 2-BYTE PLC interface or KS2000
The maximum DP buffer sizes can be modified in Table 100, although it is necessary for the Bus Coupler to be reset
(power off/power on, or a software reset) before the new value is adopted:
Register Description
2 maximum length of input data
3 maximum length of output data
4 maximum length of diagnosis data
5 maximum length of configuration data