Bosch Rexroth Tightening System 350 - Page 311

3 608 878 300 Tightening Technology | Bosch Rexroth AG 311/641
System 350 | 3 608 878 300/2019-03
Telegram number
The telegram number is an integer. The telegram counter starts with 1 and increments continuously. The
telegram counter of the last package is transmitted as negative value. This identifies the end of
transmission.
This means that three telegrams are numbered 1 to 3. The PLC will then put the process data together
again based on the telegram number.
Length
The telegram length contains the number of the process data residing on the field bus. The length is the
"true" length, starting after the header (length without header content).
Sequence
The PLC reads process data by writing a command to the input/output area.
The input/output field directly follows the PLC input/output signals. The normal sequence of the results
data request via the extended send range contains the following steps:
• The PLC reads the command (status word) which must be zero. If the command is unequal to zero,
the PLC confirms this by writing zero to the command (control word). This signals that the previous
result has been processed.
• The PLC waits until the mirrored command (status word) becomes zero. This signals that the
nutrunner is ready to receive a new command.
• The PLC writes the next command (control word).
• The PLC waits until the command received (status word) is equal to the command sent (control
word). This signals that the nutrunner confirms receipt and execution of the command.
• After having read the data, the PLC writes zero to the command (control word), confirming that it has
read the result.
• This sequence is repeated until the telegram number in the header is negative.
Figure 6–59 illustrates the flow chart of a results data request for the extended send range.
NOTICE
Loss of data
The PLC must actively request the tightening results using the 0x1100 command. Results not actively
requested by the PLC are lost for any further process steps.
 When programming, ensure that the PLC will always request the results.