Beckhoff BC8050, Documentation

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RS232 - Interface
BC8050 und BC8150 75 Version: 3.0.0
The data packets are transferred in a fixed format as a binary string. The data frame is set to 8 data bits, with
even parity and 1 stop bit (8E1). The baud rate is preset to 38400 baud.
The station addresses are set to Bus Coupler/Fieldbus Box via two rotary switches. If address 0 is set, the
BK8x00/IPxxxx-B8x0 operates as master, and the slave Bus Coupler/Fieldbus Box must be allocated
address 1.
Request
The master sends a request to the slave with the process output data to be transferred. The slave responds
by sending its status and its process input data.
Byte Description Valid range of values
0 Start ID "P" (0 x 50 hex)
1 Number of process data output words 0..255
2 Message Ident 0..255
3 Multipoint address 0..99 for BK8x00
0..69 for IP/ILxxxx-B8x0
4 + 2 x n
n = 0...125 Process data output: Low Byte 0..255
5 + 2 x n Process data output: High Byte 0..255
6 + 2 x n +1 Checksum 0..255
Start ID
The start ID consists of one byte. It identifies the start of a data packet.
Number of process data output words
The number of process data output words specifies the size of the output process image of the addressed
Bus Coupler/Fieldbus Box in words. If the number of process image bytes is odd it must be rounded up.
Enter zero if only the process input data of the Bus Coupler/Fieldbus Box are to be read.
Message Ident
The message Ident is a (freely selectable) value returned by the receiver in the response string, so that the
sender can correlate received and sent strings.
Multipoint address
The multipoint address specifies the receiver. The address value must be unequal 0, since 0 is the master
address. For Fieldbus Boxes please note that addresses greater than 69 are not permitted.
Process data output
The process data outputs are entered as data words in Intel format.
Checksum
The checksum is formed by adding up the contents of the individual bytes (total request string, without
checksum byte). Any overflow is not taken into account.
Response
The Bus Coupler/Fieldbus Box responds to a request by the master.