GE PACSystems RXi User Manual

Chapter 8. Gigabit Ethernet (GbE) Interface Overview and Operation152 PACSystems* RXi Distributed IO Controller User Manual GFK-2816F(Words 7 and up) Data Block: The Data Block defines the Channel command to be performed.For information on how to fill in the Channel command information, refer to the next sections.Status DataSeveral types of status data are available to the client application program.LAN Interface Status Bits (LIS Bits)The LIS bits comprise bits 1–16 of the 80-bit status area. The location of this 80-bit statusarea is assigned using the Configuration software. The LIS bits contain information on thestatus of the Local Area Network (LAN) and the Ethernet interface.Channel Status BitsThe Channel Status bits comprise bits 17–48 (32 bits) of the 80-bit status area. When usedfor Modbus TCP channels, these bits consist of a Connection Open bit and an unused bit foreach channel.Status bits for unused channels are always set to zero.The status bits are updated in the CPU once each controller scan by the Ethernet interface.These bits can be used to prevent initiation of a COMMREQ function when certain errorsoccur or to signal a problem on an established channel. The starting location of these bits isset up when the module is configured.For definitions of the LIS and Channel Status bits, refer to Ethernet Interface Status Bits onpage 191.COMMREQ Status Word (CRS Word)The 16-bit CRS word receives the initial status of the communication request. The location ofthe CRS word is assigned for each COMMREQ function in the COMMREQ Command Block.The CRS is not updated in the CPU each scan. It is generally used to determine the cause ofa communication error after the COMMREQ function is initiated. The cause is reported in theform of an error code. The COMMREQ Status word (CRS word) is returned from the Ethernetinterface to the RXi CPU immediately if the Command Block contains a syntax error or if thecommand is local.The COMMREQ Status word (CRS word) reports status in the format shown below. The CRSword location is specified in Words 3 and 4 of the Command Block.Hex FormatHigh Low00 00Minor Error Codes (high byte)Success and Major Error Codes (low byte)CRS Word inRefer to Section 8.6.5, Major and Minor Error Codes in the COMMREQ Status Word forCOMMREQ error codes that could be reported in the CRS words for Modbus TCPcommands.