Rockwell Automation T3831 User Manual
ICS Regent
®
PD-6041
Communications Package for
W
INTERPRET
Guarded Peer-Link Communications
(T3831)
Issue 1,
The W
ware package that allows you to configure Guarded Peer-Link
communications for interconnected Regent systems. Using
Guarded Peer-Link, multiple Regent systems can transfer
safety-critical data between each other for distributed safety
interlocking within a plant. Using redundant networks and
communications modules, the peer-to-peer communications
are protected against single points of failure.
INTERPRET Communications Package is an add
March, 06
-
in soft
-
Features
·
Multidrop peer-to-peer communications between two to 31
Regent controllers.
·
Supports single and redundant networks
legs).
·
Deterministic protocol suitable for transfer of safety-critical
data between Regent systems.
·
TÜV certified, Risk Class 5.
·
Transfer up to 6,500 variables over the network.
·
Each leg of a redundant network is Mastered by a separate
Regent system.
·
Full status monitoring and alarming of the network through
system variab
(from one to five
les in each Regent.
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Communications Package for
Important!
W
INTERPRET
(T3831)
Software Installation
The Communications package is installed on the PC running
the WINTERPRET
package provides the necessary installation software to install
this add-in communications package. The communications
package should be installed at the same time or after you
have installed the WINTERPRET
Installation Procedure
The files on the Communications package diskette are in
compressed form. You cannot simply copy
hard drive — they must be decompressed before they will run.
You must have the WINTERPRET base package distribution
disk in order to run the setup procedure to install the
Communications package.
To install the Communications package, use the following
sequence:
1. Insert the WINTERPRET base package distribution disk into
drive A: or B:
application software. The W
base package.
the files to your
INTERPRET
base
2. Start Windows (if it isn’t already running).
3. Choose Run from the Program Manager’s File menu.
4. Type a:\
W
INTERPRET base package disk in drive B: type
b:\setup.exe
5. In the WINTERPRET Setup dialog box enter the name of the
directory in which you have installed the WINTERPRET
base package (This assumes that you have already
installed WINTERPRET). Choose Continue.
6. In the WINTERPRET Installation dialog box check the
Communications package box.
7. Choose OK to have the setup program install the
Communications package software.
When the installation is completed, you can run the
W
INTERPRET application and define the Guarded Peer
communications variables and projects. For detailed
guidelines on configuring the Guarded Peer-Link
setup.exe
.) Choose OK or press ENTER.
in the text box. (if you inserte
d the
-
Link
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Communications Package for
communications see Configuring the Guarded Peer-Link,
starting on page 11.
W
INTERPRET
(T3831)
Guarded Peer-Link Operation
Guarded Peer-Link communications allow multiple Regents to
send and receive data over a bussed serial communications
network. This multidrop network can be made redundant by
using up to five separate multidrop legs, ea
serial ports on the Regent communications modules. An
example is shown in Figure 1.
ch connected to
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Figure 1. Guarded Peer-Link Communications Network.
Each leg of the GPL network requires one Regent to act as the
GPL Master for the leg. When redundant legs are used for
fault tolerance, each leg has a unique GPL master. For
example, in Figure 1, Regent 1 is the GPL master for network
leg 1 and Regent 4 is the GPL master of network leg 2. By
utilizing separate GPL masters for each network leg, the GPL
communications can be maintained as long as at least one
March, 06
GPL master is running.
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Communications Package for
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INTERPRET
(T3831)
Theory of Operation
Each leg of the GPL network uses a bussed multidrop RS-485
communication link for exchanging data between up to 31
Regents. When loaded and operating, the GPL
communications activity on each leg sequences through
polling commands and broadcast responses as shown in
Figure 2. The completion of this sequence for each Regent on
the network makes up a GPL communications cycle. This
cycle repeats continuously while the GPL master for the leg is
operating. Each leg of the network runs asynchronous to each
other.
Figure 2. The GPL communications cycle.
During the communications cycle the GPL master issues a
poll command to a Regent to transmit its GPL data packet.
The polled Regent broadcasts its GPL data packet which
contains all of the GPL variables configured for the Regent.
Each Regent on the network receives the broadcasted GPL
data packet and stores the contents in an internal GPL input
buffer. The GPL master then issues a poll command to the
next Regent on the network to transmit its GPL data packet.
This sequence continues until all Regents identified in the
GPL configuration have been polled and subsequently
broadcast their GPL data packets. The GPL master repeats
the communication cycle continuously.
Internal to each Regent configured for GPL communications
are input templates, output templates, input data buffers and
output data buffers. Each of these are described below.
Input Templates
The Regent has an input template for every configured node
on the network (including itself). Figure 3 illustrates the
structure of the GPL input templates for each Regent
configured for Guarded Peer-Link communications.
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Communications Package for
W
INTERPRET
(T3831)
Figure 3. Structure of the GPL Input Templates.
The input templates allow the Regent to understand the data
format of GPL variables from each Regent’s data packet and
where to copy the needed variables from the input buffers into
this Regent’s I/O and shared variables. In addition, the input
template contains initial and final values for each variable (as
configured in the I/O or shared variable editors). The initial
value will be used when the Regent powers up (warm starts),
until subsequent GPL data packets are received. The final
valu
e is used for input variables when input data is not
received from a particular node on the network (all of the
input buffers for the node have timed out on all legs, see GPL
Fault Handling, starting on page 8).
The total size of the GPL input template in each Regent will
be:
GPL Input Template = 20 * (No. of Nodes) + 10 * (Qty of Variables) + 12 bytes
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Communications Package for
W
INTERPRET
(T3831)
Input Data Buffers
Each Regent connected to a GPL network with “L” legs has
2*L input data buffers for each node on the network
(including itself). For example a GPL network with two legs
(dual redundant) has 4 input data buffers for each node (two
for each leg). Each of these data buffers is the size of the GPL
data packet from the associated node. Figure 4 illustrates the
structure of the GPL input data buffers in each Regent
configured for Guarded Peer-Link communications.
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Figure 4. Structure of the GPL Input Data Buffers.
When an incoming GPL data packet is received it is stored in
one of the two buffers for the leg of the network the data was
received and the input data buffer is marked as “most recent.”
The previous “most recent” input data buffer is marked as
“empty.” At the end of the application program scan, the
Regent will use the input data buffer that is marked as most
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Communications Package for
W
INTERPRET
(T3831)
recent to transfer the input GPL variables into the Regent’s
shared variables and I/O memory areas (as defined by the
input templates).
Output Template
The Output Template is used to identify which variables in
the Regent are configured as GPL variables that this Regent
provides to the GPL network. Figure 5 illustrates the
structure of the GPL output template for an individual
Regent configured for Guarded Peer-Link communications.
Figure 5. Structure of the GPL Output Template.
At the end of each application program scan the Regent uses
the definitions in the output template to load its primary GPL
output data buffer with the GPL output variables.
Output Data Buffers
Each Regent connected to a GPL network with “L” legs has
L+1 output data buffers. One is a primary output data buffer
and the others are individual output data buffers for each leg
of the network. Figure 6 illustrates the structure of the GPL
output data buffers for a Regent configured for Guarded Peer
Link communications.
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Communications Package for
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INTERPRET
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Figure 6. Structure of
the GPL Output Data Buffers.
Each buffer is the size of the GPL data packet that this
Regent provides to the network. At the end of each
application program scan, the values of the variables
configured for GPL are copied into the primary output data
buffer. When the Regent receives its GPL poll command from
a particular leg of the network, the primary output data buffer
is copied to the output data buffer for that leg and the Regent
broadcasts its GPL data from this buffer to the particular leg
of the net
GPL Fault Handling
work.
During GPL operations, each Regent performs fault detection
and fault handling for the GPL communications, regardless of
whether it is a GPL Net Master or Net Slave. The input
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Communications Package for
Communications Error
Explanation
Parity
The communications module UART detects a
parity error for character.
Framing
The communications module UART detects a
data framing error.
Character over-run
The communications module UART detects a
character over-run.
Packet CRC
The Regent validates the CRC for a received
packet.
Intercharacter time-out
The Regent detects an intercharacter time-out
condition (5 character times).
Packet echo time-out
The Regent detects that a node has not started
to transmit a response to a poll request in the
allotted time (20 milliseconds).
Remote activity time-out
The Regent reports an error when no
communications activity occurs on a GPL port for
allotted time (2 seconds).
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INTERPRET
(T3831)
templates in each Regent provide a complete definition of the
entire GPL network configuration.
When the GPL communications are active (see Connect
Network, starting on page 22) each Regent monitors the
activities of the GPL network for the types of errors listed in
Table 1. A brief explanation accompanies each type of error.
When the Regent detects errors on the GPL communications,
it reports these errors using system variable control relays.
Internally the Regent filters these faults to mask
intermittent failures. When a fault occurs repeatedly, then
fault bits are set and certain fault handling responses may
occur.
Table 1. Guarded Peer-Link Communications Errors.
transient or
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For example if a Regent fails to receive data from a particular
node on the network, a fault bit will be set and the GPL input
data variables associated with that node will be set to their
configured final values.
GPL System Variables
There are 49 system variable control relays that are defined
for GPL status and fault reporting. These variables should be
monitored as appropriate in the application programs or
operator interface to notify plant personnel about the status of
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Communications Package for
Variable Name
Description
GPLPxMASTER
Port x is configured as a GPL Net Master Port — x
is
the port number (2 through 5). This bit turns on after
loading the Regent serial ports definition.
GPLMSTRSCAN
The GPL master is scanning. If the Regent is
configured as a GPL Net Master, this bit is on after the
Start Network command is performed.
GPLCONNECT
The Regent is connected to GPL. Once the Connect
Network command is performed, this bit is on to
indicate the GPL Network functions are active.
GPLINTEMP
The GPL input template is defined. This bit is on after
the Load Network command is performed, to indicate a
valid input template is loaded.
GPLOUTTEMP
The GPL output template is defined. This bit is on after
the Load Network command is performed, to indicate a
valid output template is loaded.
GPLSCANONE
First GPL scan. This bit is on after the Connect
Network command is first performed and remains on
until several GPL communications cycles have
completed successfully.
GPLDATAxx
GPL Node xx has provided fresh data — xx
ranges from
01 to 31. When GPL is successfully running, the
GPLDATAxx bit is on for each configured GPL node.
While the GPL is running, if a GPLDATAxx bit turns off,
it indicates that this Regent is no longer rece
iving fresh
data from node xx.
GPLFLTANYBUS
Fault on any GPL bus. This bit turns on if any type of
fault is detected for GPL. Normally accompanied by
GPLPxFAULT bit(s).
GPLPxFAULT
Port x GPL bus fault. This bit turns on if a fault is
detected for a specific communications port for GPL —
x ranges from 1 to 6, representing the communications
port number of the Regent.
GPLFLTLOCAL
GPL local bus has a fault. This bit turns on when the
Regent detects a local fault using a loopback
verification test when i
t transmits its own GPL packets.
Normally this fault indicates a communications module
fault, or cable disconnected.
GPL communications. A brief description of each of these
variables is provided in Table 2.
W
INTERPRET
(T3831)
Table 2. GPL System Variables.
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