PN/CAN Gateway, PROFINET/CANopen Slave | Version 2 | 1/26/2021
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7.3.1
Transfer of SDO data > 4 Byte
VISIBLE-STRING:
The data must be read or written continuously from the beginning to the end,
starting at byte index 0. The byte offset must be increased in steps of 4 bytes for each job. Offset 0 is
the indicator for a new transmission. The last write operation must be performed with 'Freeze' = 0.
This also redefines the length of the string. It must not exceed the maximum length from the EDS
definition.
When reading, the 'Freeze' bit may be set during the last transfer, since the string length may be
shorter than the EDS agreement. In this case it is internally forced to 0. Only as much is read as is
available (actual block length read is in SDO status). The SDO is always released during the last
transfer.
A string must always be read until the 'Freeze' bit becomes 0. Otherwise the SDO remains blocked. An
abort of reading is always possible in the job with 'Freeze' = 0.
Only characters >= 0x20 and <= 0x7F may be included, otherwise error message 0x06000030 is issued.
An end NULL must not be transmitted !
In practice, it is recommended to fill up with spaces up to the length agreed in the EDS file.
OCTET-STRING:
Here it is possible to read and write in blocks of 1..4 Byte. The offset is to be
indicated here as byte offset! The length of the OCTET STRING remains constant according to the EDS
file and is limited of a maximum of 120 bytes. The offset must not exceed this length. During
writing and reading the SDO remains locked during 'Freeze' = 1. The 'Freeze' bit in the order may be
set when reading over the end. In this case it is internally forced to 0.
If the reading is to be aborted before the end of the OCTET STRING, the 'Freeze' bit in the job must be
0, otherwise the SDO remains disabled.
For the random writing and reading of SDOs, we will gladly provide you with a sample program. Please
ask the support at
