FANUC Robotics America GFK-1541B User Manual

“Communications Request” is a term used to describe all the user elements required for correctly
initiating

 Channel commands from a Series 90 PLC.  This section describes the elements of the

Communications Request.

No programming of Communications Requests is required for PLCs acting as servers, which are
merely targets of other systems’ requests, but do not themselves initiate requests.

The Communications Request is made up of the following elements:

ƒ 

The COMMREQ Function Block (ladder instruction)

ƒ 

The COMMREQ Command Block

ƒ 

The Channel Command

ƒ 

Status Data (COMMREQ Status word, LAN Interface Statusand Channel Status bits)

ƒ 

The logic program controlling execution of the COMMREQ Function Block

The figure below illustrates the relationship of these elements:

The COMMREQ Function Block is the ladder instruction that triggers the execution of the
Channel command.  In the COMMREQ Function Block, you specify the rack and slot location of
the Ethernet Interface, a task value, and the address of a location in memory that contains the
Command Block.  There is also a fault output on the COMMREQ Function Block that indicates
certain programming errors.

a44916c

INPUTS

AND

OUTPUTS

FOR COMMREQ

FUNCTION

COMMAND

BLOCK

ADDRESS

DETAILS
OF THE

CHANNEL
COMMAND

STATUS

CODES

COMMREQ

STATUS

WORD

ADDRESS

LAN INTERFACE STATUS

AND CHANNEL STATUS

BITS

INITIATES

COMMREQ

FUNCTION

BLOCK

Location in PLC memory

specified when configuring

the Interface using

Configuration Software

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