Pcom - Phase Communication - Siemens 353 User Manual

Function Blocks

3.2.66 PCOM - Phase COMmunication

The Phase Communication PCOM function block is
available on a one per loop basis to enable
communication with a higher level device, such as a PC
running a batch management software program. When
the controller configuration is structured such that logic
operations are partitioned in small phase operations, the
PCOM block facilitates the interface between the logic
controlling the overall phase operations for the batch
and the logic performing the control logic for each
phase.
The logic performed by the PCOM block is detailed in
Boolean form in Figure 3-1. Network communication
can be either Modbus or Modbus/TCP. Details are
listed in Section 5 Network Communications. The
LOOP # configured in the ODC or ODS function block
for the loop determines the location of the status coils in
the Modbus mapping. Communication states are
represented in Figure 3-1, on the next page, using the
symbols shown below. Modbus states are mapped in
coils as defined in Section 6.3.9 PCOM Block Status.
Read/Write States
Each communication state is read as a 1 or 0. Using Modbus, a write of a 1 (W1) or a 0 (W0) will affect the
communication state as defined by the associated logic in Figure 3-1. All unconfigured inputs will be treated as low
(0) except OK, RD, RN and HE which will be treated as high (1). Three of the output states, EO ("EMERG"), IK
("INTRLK"), and FD ("FAILED") can be configured for priorities 0-5. This will affect the flashing, etc. as
previously described for other controller status conditions. These states also have unacknowledged bits as detailed
in status word 2. Conditions that require acknowledging can be acknowledged by either using the local faceplate
ACK button or by writing to the individual not acknowledged bit or the Not Ack'd PCOM bit.
3-68
R 0
Read States
START
W 1
W 0
Phase COMunication
PCOM
EO
Emerg. OR Phase
Communication
OK
INT_OK
PF
Phase_Fail
RD
ReaDy
RN
RuN
HE
HEld
DN
DoNe
E O P R I O R
Emerg. Override PRIORity ... 0,1,2,3,4,5
P
I K R I O R
InterlocKed PRIORity ........... 0,1,2,3,4,5
D F P R I O R
Device Fail PRIORity ............ 0,1,2,3,4,5
U
I N P T E O
INPUT EO ............
I N P U T O K
INPUT OK ............
I N P U T P F
INPUT PF ............
P U
I N T R D
INPUT RD ............
I N P U T R N
INPUT RN ............
U
I N P T H E
INPUT HE ............
I N P U T D N
INPUT DN ............
E S N
Exec. Seq. No. .................... 000 to 250
RUN
UM353-1B
EO
Emerg. OR
IK
InterlocKed
FD
FaileD
RS
ReSet
EN
ENabled
ST
STart
HO
HOld
(4)
(4)
(4)
loop tag.block tag.output ( null )
loop tag.block tag.output ( null )
loop tag.block tag.output ( null )
loop tag.block tag.output ( null )
loop tag.block tag.output ( null )
loop tag.block tag.output ( null )
loop tag.block tag.output ( null )
(000)
R 1/0
April 2012