Mechanics Of The Commreq Instruction - GE GFK-2892F User Manual

Mechanics of the COMMREQ Instruction

Once the content of the of the COMMREQ communication has been set up (in the COMMREQ Command Block, as
described above) the application program will need to activate the corresponding COMMREQ instruction in order to initiate
communications with the target Genius Device (via the interconnected PROFINET Controller and Genius Gateway.
This section describes the mechanisms employed by the PLC logic to initiate and monitor the COMMREQ instruction and its
aftermath.
The COMMREQ instruction has four inputs and two outputs:
COMMREQ Inputs
COMMREQ Description
Input
(enable) Permissive logic that controls power flow to the COMMREQ function block.
IN The memory location of the Command Block containing the specific COMMREQ command information.
The Command Block may be located in any word–oriented area of memory (%P, %L, %R, %AI, %AQ, or
%W).
SYSID A two-byte hex value that gives the rack and slot location of the controlling PROFINET Controller. The
rack number must be zero and occupies the more significant byte; the slot number in which the
PROFINET Controller is located occupies the less significant byte. Example:
Rack#
0
TASK The task is 16#0084 for the IC695PNC001.
The task is 16#0002 0084 for the IC695CPE330 and IC695CPE400.
Thus, the input specifies the conditions under which the COMMREQ is to be activated, and specifies which
PROFINET Controller and which Genius Gateway are targeted in this activity.
COMMREQ Outputs
COMMREQ Output Description
OK Indicates correct execution of the COMMREQ.
FT Indicates a fault condition in COMMREQ execution.
The behavior of the COMMREQ Outputs is shown in the following truth table. Note that the OK and FT outputs
are never both true at the same time:
Enable Error?
active no
active yes
not active no execution
The COMMREQ passes power flow to its OK output unless:
•
The specified module (in rack/slot) is not present.
•
The specified task is not valid for the target device.
•
The data length is zero.
If any fault intrinsic to the conduct of the COMMREQ occurs, power flow passes to the FT output instead.
If there are errors in the portion of the Command Block used specifically by the PROFINET Controller or Genius
Gateway (for example, the Device Number entered is incorrect), these errors are reflected in the value
returned in the Status Block location, not in the FT output.
GFK-2892F
Slot# Resulting SysID Hex Word Value
4 0004h
OK FT
true false
false true
false false
Chapter 6. COMMREQ/Data_Init_Comm Programming
March 2019 55