Applies To:
  • CitectSCADA 5.xx, 6.00
  • CitectHMI 5.xx, 6.00

I am getting S7NT driver error code 0x227A in the syslog.dat file. What does this error mean and how can I resolve this situation?

0x227A is documented as GENERIC_GENERAL_ERROR, S7_ERR_MAX_REQ. This means the S7 API receives more requests than it can handle. See also Q3807. The Siemens Softnet S7 API has a limitation of a maximum of 2 simultaneous commands from a single external connection.

Version of the S7NT driver includes a number of modifications to cater for heavily loaded systems that experience large numbers of timeouts (including system receiving error 0x227A). Changes include:
- Improved DCB queue handling during timeout operations
- Correct use of SoftNet API timeouts
- Improved handling of late or missing responses from the SoftNet API
- Improved management of maximum outstanding request
- New driver statistic added 'Outstanding API Req.' detailing the number of outstanding API requests
- Connection timeout events are now fatal, causing unit or channel offline and will not generate a re-try. (normal read/write operations unaffected)

If you are receiving 0x227A driver errors it is recommended to upgrade to version or later of the S7NT driver.

S7NT unit channel offline timeout error