Baumer GK473 - Manual (Page 25)

Manual_GK473_DeviceNet_EN.doc 25/31 Baumer IVO GmbH & Co. KG
04.05.11 Villingen-Schwenningen, Germany
8 General information
8.1.1 Broadcast commands
Due to the bus conflict, SPAs are generally not in a position to reply via RS485 interface to broadcast
commands, i.e. to commands addressed to all SPAs at the same time (identifiers 99, 83h). Therefore, on
behalf of the SPA the gateway will reply to the DeviceNet master. The response is only confirming that the
broadcast command was transmitted by RS485 interface to all SPAs. It does NOT mean any
acknowledgement of acceptance or accomplishment at the end of the SPAs.
8.1.2 Interface documentation
The respective SPA’s interface description(s) is giving complete information on the SPA interface. The
interface description is mandatory for implementing a gateway application.
8.2 Automated gateway functions
8.2.1 Automatic SPA recognition
After switchon the gateway proceeds an AutoScan operation of all SPA identifiers and stores those
encountered in the internal memory what takes about 15 seconds and enables later polling the identifiers of
all connected SPAs to verify whether they are existing .
The function “Automatic SPA recognition” takes for granted that all SPAs have been switched on prior to or
together with the gateway.
8.2.2 Cyclic scanning of all SPAs connected
During operation the gateway is scanning automatically all SPAs connected to verify whether they are „in
position“ or in error state. Polling this information is only by I/O, COS (Change of State) or by Explicit
Message.
8.2.3 Error messages
There are two kinds of messages: Those of a SPA and a gateway.
They are broken down into three groups:
1.) DeviceNet error messages DeviceNet Master <-> GK437 Slave
They are processed according to the DeviceNet Specification.
2.) Error messages during read/write operations of a sub bus user
The SPA is sending an error message after a transparent command. Regarding the respective content of the
message please refer to the SPA interface description. State of the art are messages indicating a “format
error” or “CRC error”.
3.) Error messages upon Change of State incident at sub-bus
Alterations are output by batched information explicit, immediately by implemented COS connection or by I/O
poll.
• SPA in Timeout State. A sub bus user didn’t reply within 120 ms.
• SPA in Error State. A motive operated spindle position display informs on missing motor supply.