Status data, Types of status data – FANUC Robotics America GFK-1541B User Manual

Page 98

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GFK-1541B

Chapter 3 Programming Channel Commands

3-31

3

Status Data

This section describes all the status data that is available to the ladder program to determine the
state of the Ethernet Interface and its channels.

Types of Status Data

There are four main types of status data available to your ladder program:

1.

OK Output of the COMMREQ Function Block. (Series 90-70 PLCs only)

This output is set

if the PLC CPU was successful in transferring the COMMREQ data from the reference table
memory specified by the COMMREQ function block into the memory local to the Ethernet
Interface. This does not indicate that the Ethernet Interface has processed the COMMREQ,
only that it has been received by the Ethernet Interface.

Barring ladder programming errors, the OK and FT outputs should not both be set in the
same scan by the same COMMREQ.

2.

FT Output of the COMMREQ Function Block.

This output is set if there is a programming

error in the COMMREQ Function Block itself, if the rack and slot specified in the
COMMREQ SYSID parameter is not configured to contain an Ethernet Interface, or if the
data block length specified in the Command Block is out of range. This output also may
indicate that no more COMMREQ functions can be initiated in the ladder program until the
Ethernet Interface has time to process some of the pending COMMREQ functions.

If the FT Output is set, the CPU does not transfer the Command Block to the Ethernet
Interface. In this case, the other status indicators are not updated for this COMMREQ.

3.

Status Bits.

The status bits are updated in the CPU once each PLC scan by the Ethernet

Interface. These bits are generally used to prevent initiation of a COMMREQ function when
certain errors occur or to signal a problem on an established channel. The status bits include
the LAN Interface Status bits and the Channel Status bits. The starting location of these bits
is user-configurable.

The LAN Interface Status bits monitor the health of the Ethernet Interface itself, such as the
LAN Interface OK bit and the AUI/BNC Fuse Blown bit for Series 90-70 PLCs (AAUI Fuse
Blown bit for Series 90-30 PLCs). The Channel Status bits monitor the health and progress
of a channel established using the Establish Read/Write Channel commands.

4.

Communications Status Words.

There are two types of words that provide detailed

information: The COMMREQ Status word (CRS word) and the Detailed Channel Status
words (DCS words). The communications status words are not updated in the CPU each
scan as are the status bits. They are generally used to determine the cause of a
communications error after the COMMREQ function is initiated. The cause is reported in
the form of an error code described later in this section.

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