Chapter 6. COMMREQ/Data_Init_Comm Programming
GFK-2892F
March 2019
55
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
Input
Description
(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# Slot# Resulting SysID Hex Word Value
0
4
0004h
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?
OK
FT
active
no
true
false
active
yes
false true
not active no execution false false
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.
