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3.2.4.3
Memory Allocation Configuration
Memory Parameters
Reference Points
%I Discrete Input, %Q Discrete
Output, %M Internal Discrete, %S
System, %SA System, %SB System,
%SC System, %T Temporary Status,
%G Genius Global
The upper limit for the range of each of these memory types. Read only.
Total Reference Points
Read only. Calculated by the programming software.
Reference Words
%AI Analog Input
Valid range: 0 through 32,640 words.
Default: 64
%AQ Analog Output
Valid range: 0 through 32,640 words.
Default: 64
%R Register Memory
Valid range: 0 through 32,640 words.
Default: 1024.
%W Bulk Memory
Valid range: 0 through maximum available user RAM.
Increments of 2048 words.
Default: 0.
Total Reference Words
Read only. Calculated by the programming software.
Managed Memory
Symbolic Discrete (Bits)
The configured number of bits reserved for symbolic discrete variables.
Valid range: 0 through 83,886,080 in increments of 32768 bits.
Default: 32,768.
Symbolic Non-Discrete (Words)
The configured number of 16-bit register memory locations reserved for
symbolic non-discrete variables.
Valid range: 0 through 5,242,880 in increments of 2048 words.
Default: 65,536.
I/O Discrete (Bits)
The configured number of bits reserved for discrete IO variables.
Valid range: 0 through 83,886,080 in increments of 32768 bits.
Default: 0
I/O Non-Discrete (Words)
The configured number of 16-bit register memory locations reserved for
non-discrete IO variables.
Valid range: 0 through 5,242,880 in increments of 2048 words.
Default: 0
Total Managed Memory Required
(Bytes)
Read only. See
Calculation of Memory Required for Managed Memory
.
Total User Memory Required (Bytes)
Read only. See
Calculation of Total User Memory Configured
.
Point Fault References
The Point Fault References parameter must be enabled if you want to use
fault contacts in your logic. Assigning point fault references causes the
CPU to reserve additional memory.
When you download both the HWC and the logic to the PLC, the
download routine checks if there are fault contacts in the logic and if
there are, it checks if the HWC to download has the Point Fault References
parameter set to Enabled. If the parameter is Disabled, an error is
displayed in the Feedback Zone.
When you download only logic to the PLC, the download routine checks if
there are fault contacts in the logic and if there are, it checks if the HWC
on the PLC has the Point Fault References parameter set to Enabled. If the
parameter is Disabled, an error is displayed in the Feedback Zone.
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3.2.5
Fault Parameters
You can configure each fault action to be either diagnostic or fatal.
A diagnostic fault does not stop the PLC from executing logic. It sets a diagnostic variable and is
logged in a fault table.
A fatal fault transitions the PLC to the Stop Faulted mode. It also sets a diagnostic variable and is
logged in a fault table.
Fault Parameters
Loss of or Missing
Rack
(Fault group 1.) When BRM failure or loss of power loses a rack or when a configured
rack is missing, system variable #LOS_RCK (%SA12) turns ON. (To turn it OFF, fix the
hardware problem and cycle power on the rack.)
Default: Diagnostic.
Loss of or Missing
I/O Controller
(Fault group 2.) When a Bus Controller stops communicating with the PLC or when a
configured Bus Controller is missing, system variable #LOS_IOC (%SA13) turns ON. (To
turn it OFF, replace the module and cycle power on the rack containing the module.)
Default: Diagnostic.
Loss of or Missing
I/O Module
(Fault group 3.) When an I/O module stops communicating with the PLC CPU or a
configured module is missing, system variable #LOS_IOM (%SA14) turns ON. (To turn it
OFF, replace the module and cycle power on the rack containing the module.)
Default: Diagnostic.
Loss of or Missing
Option Module
(Fault group 4.) When an option module stops communicating with the PLC CPU or a
configured option module is missing, system variable #LOS_SIO (%SA15) turns ON. (To
turn it OFF, replace the module and cycle power on the rack containing the module.)
Default: Diagnostic.
System Bus Error
(Fault group 12.) When a bus error occurs on the backplane, system variable #SBUS_ER
(%SA32) turns ON. (To turn it OFF, cycle power on the main rack.)
Default: Fatal.
I/O Controller or
I/O Bus Fault
(Fault group 9.) When a Bus Controller reports a bus fault, a global memory fault, or an
IOC hardware fault, system variable #IOC_FLT (%SA22) turns ON. (To turn it OFF, cycle
power on the rack containing the module when the configuration matches the hardware
after a download.)
Default: Diagnostic.
System
Configuration
Mismatch
(Fault group 11.) When a configuration mismatch is detected during system power-up or
during a download of the configuration, system variable #CFG_MM (%SA9) turns ON. (To
turn it OFF, power up the PLC when no mismatches are present or download a
configuration that matches the hardware.)
This parameter determines the fault action when the CPU is not running. If a system
configuration mismatch occurs when the CPU is in RUN Mode, the fault action will be
Diagnostic. This prevents the running CPU from going to STOP/FAULT mode. To override
this behavior, see
Configuring the CPU to Stop Upon the Loss of a Critical Module
.
Default: Fatal.
Fan Kit Failure
(Fault group 0x17.) When a fault is detected in the Smart Fan kit, system variable
#FAN_FLT (%SA7) turns ON. (To turn a fan kit fault OFF, clear the Controller fault table or
reset the PLC.)
Default: Diagnostic.
Recoverable Local
Memory Error
Redundancy CPUs only. (Fault group 38) Determines whether a single-bit ECC error
causes the CPU to stop or allows it to continue running.
Choices: Diagnostic, Fatal.
Default: Diagnostic.
Note: When a multiple-bit ECC error occurs, a Fatal Local Memory Error fault (error
code 169) is logged in the CPU Hardware Fault Group (group number 13).
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Fault Parameters
CPU Over
Temperature
(Fault group 24, error code 1.) When the operating temperature of the CPU exceeds the
normal operating temperature, system variable #OVR_TMP (%SA8) turns ON. (To turn it
OFF, clear the Controller Fault Table or reset the PLC.)
Default: Diagnostic.
Controller Fault
Table Size
(Read-only.) The maximum number of entries in the Controller Fault Table.
Value set to 64.
I/O Fault Table
Size
(Read-only.) The maximum number of entries in the I/O Fault Table.
Value set to 64.
3.2.5.1
Configuring the CPU to Stop Upon the Loss of a Critical Module
In some cases, you may want to override the RUN Mode behavior of the System Configuration
Mismatch fault. A given module may be critical to the PLC’s ability to properly control a process. In
this case, if the module fails then it may be better to have the CPU go to STOP Mode, especially if the
CPU is acting as a backup unit in a redundant system.
One way to cause the CPU to stop is to set the configured action for a Loss-of-Module fault to Fatal
so that the CPU stops if a module failure causes a loss-of-module fault. The correct loss-of-module
fault must be chosen for the critical module of interest: I/O controller, I/O module, and Option
module. The Ethernet communications module is an example of an Option module.
This approach has a couple of disadvantages. First, it applies to all modules of that category, which
may include modules that are not critical to the process. Second, it relies on the content of the fault
table. If the table is cleared via program logic or user action, the CPU will not stop.
In systems that use Ethernet Network Interface Units (ENIUs) for remote I/O, a critical module of
interest may be the Ethernet module that provides the network connection to the ENIU. Other
techniques can be used to provide a more selective response to an Ethernet module failure than the
Loss-of-Option module fault. One technique is to use application logic to monitor the Ethernet
Interface Status bits, which are described in Monitoring the Ethernet Interface Status Bits in the
PACSystems RX7i & RX3i TCP/IP Ethernet Communications User Manual, GFK-2224. If the logic
determined that a critical Ethernet module was malfunctioning, it could execute SVC_REQ #13 to
stop the CPU.
Since the ENIU uses Ethernet Global Data to communicate with the PACSystems CPU, another
selective technique is to monitor the Exchange Status Words to determine the health of individual
EGD exchanges. For details on this status word, refer to Exchange Status Word Error Codes in
PACSystems RX7i & RX3i TCP/IP Ethernet Communications User Manual, GFK-2224. Because the types
of errors indicated by the exchange status word may be temporary in nature, stopping the CPU may
not be an appropriate response for these errors. Nevertheless, the status could be used to tailor the
response of the application to changing conditions in the EGD network.
In some cases the critical module may reside in an expansion rack. In that case, in addition to the
loss-of-module fault, it is recommended to set the Loss-of-Rack fault to Fatal. Then if the rack fails or
loses power, the CPU will go to STOP Mode.
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3.2.6
Redundancy Parameters (Redundancy CPUs Only)
These parameters apply only to redundancy CPUs or to those CPUs where the optional redundancy
features have been activated. For details on configuring CPU for redundancy, refer to the
PACSystems Hot Standby CPU Redundancy User Manual, GFK-2308.
3.2.7
Transfer List
These parameters apply only to redundancy CPUs. For details on configuring CPU for redundancy,
refer to the PACSystems Hot Standby CPU Redundancy User Manual, GFK-2308.
3.2.8
COM1 and COM2 Parameters
These parameters configure the operating characteristics of the CPU serial ports. COM1 and COM2
have the same set of configuration parameters. The protocol (Port Mode) determines the parameters
that can be set for each port.
Port Parameters
Port Mode
The protocol to execute on the serial port. Determines the list of parameters displayed on the
Port tab. Only the parameters required by the selected protocol are displayed.
Choices:
RTU Slave mode: Reserved for the use of the Modbus RTU Slave protocol. This mode
also permits connection to the port by an SNP master, such as the WinLoader utility
or the programming software.
Message mode: The port is open for user logic access. This mode enables C
language blocks to perform serial port I/O operations via the C Runtime Library
functions.
Available: The port is not to be used by the PLC firmware. (The CPE305 does not
support this selection.)
SNP Slave: Reserved for the exclusive use of the SNP slave. This mode permits
connection to the port by an SNP master, such as the WinLoader utility or the
programming software.
Serial I/O: Enables you to perform general-purpose serial communications by using
COMMREQ functions.
Default: RTU Slave.
Note: If both serial ports are configured for any protocol other than RTU Slave or SNP Slave,
the RUN/STOP Switch should not be disabled without first making sure that there is a
way to stop the CPU, or take control of the CPU through another device such as the
Ethernet module. The Serial I/O protocol is only active when the CPU is in RUN Mode. If
the CPU can be set to STOP Mode, it will switch the protocol from Serial I/O to the STOP
Mode protocol (default is RTU Slave). If an SNP Master, such as the programming
software in Serial mode, begins communicating on a port, the RTU protocol
automatically switches to SNP Slave. As long as the CPU can be stopped, the protocol of
the port can be auto-switched to one that enables serial programmer connection. Refer
to STOP Mode protocols.
If an Ethernet port is available, you can communicate with the CPU by connecting PME
software via the Ethernet port.
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Port Parameters
Station
Address
(RTU Slave only) ID for the RTU Slave.
Valid range: 1 through 247.
Default: 1.
Note: You should avoid using station address 1 for any other Modbus slave in a PACSystems
control system because the default station address for the CPU is 1. The CPU uses the
default address in two situations:
1.
If you power up without a configuration, the default station address of 1 is used.
2.
When the Port Mode parameter is set to Message Mode, and Modbus becomes the
protocol in STOP Mode, the station address defaults to 1.
In either of these situations, if you have a slave configured with a station address of 1,
confusion may result when the CPU responds to requests intended for that slave.
Note: The least significant bit of the first byte must be 0. For example, in a station address of
090019010001, 9 is the first byte.
Data Rate (All Port Modes, except Available.) Data rate (bits per second) for the port.
Choices: 1200 Baud, 2400 Baud, 4800 Baud, 9600 Baud, 19.2k Baud, 38.4k Baud, 57.6k Baud,
115.2k Baud.
Default: 19.2k Baud.
Data Bits (Available only when Port Mode is set to Message mode or Serial I/O.) The number of bits in a
word for serial communication. SNP uses 8-bit words.
Choices: 7, 8.
Default: 8.
Flow
Control
(RTU slave, Message Mode, or Serial I/O.) Type of flow control to be used on the port.
Choices:
For Serial I/O Port Mode: None, Hardware, Software (XON/XOFF).
For all other Port Modes: None, Hardware.
Default: None.
Note: The Hardware flow-control is RTS/CTS crossed.
Parity
(All Port Modes, except Available.) The parity used in serial communication. Can be changed if
required for communication over modems or with a different SNP master device.
Choices: None, Odd, Even.
Default: Odd.
Stop bits
(Available only when Port Mode is set to Message Mode, SNP Slave or Serial I/O.) The number of
stop bits for serial communication. SNP uses 1 stop bit.
Choices: 1, 2.
Default: 1.
Physical
Interface
(All port modes except Available.) The type of physical interface that this protocol is
communicating over.
Choices:
2-wire: There is only a single path for receive and transmit communications. The
receiver is disabled while transmitting.
4-wire: There is a separate path for receive and transmit communications and
the transmit line is driven only while transmitting.
4-wire Transmitter on: There is a separate path for receive and transmit
communications and the transmit line is driven continuously. Note that this
choice is not appropriate for SNP multi-drop communications, since only one
device on the multi-drop line can be transmitting at a given time.
Default: 4-wire Transmitter On.
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Port Parameters
Turn
Around
Delay Time
(ms)
(Available only when Port Mode is set to SNP Slave.) The Turn Around Delay Time is the minimum
time interval required between the reception of a message and the next transmission. In 2-wire
mode, this interval is required for switching the direction of data transmission on the
communication line.
Valid range: 0 through 2550ms, in increments of 10 ms.
Default: 0.
Timeout (s) (Available only when Port Mode is set to SNP Slave.) The maximum time that the slave will wait to
receive a message from the master. If a message is not received within this timeout interval, the
slave will assume that communications have been disrupted, and then it will wait for a new
attach message from the master.
Valid range: 0 through 60 seconds.
Default: 10.
SNP ID
(Available only when Port Mode is set to SNP Slave.) The port ID to be used for SNP
communications. In SNP multi-drop communications, this ID is used to identify the intended
receiver of a message. This parameter can be left blank if communication is point to point. To
change the SNP ID, click the values field and enter the new ID. The SNP ID is up to seven
characters long and can contain the alphanumeric characters (A through Z, 0 through 9) or the
underline (_).
Specify
STOP Mode
(All port modes except Available.) Determines whether you accept the default STOP Mode or set it
yourself.
Choices:
No: The default STOP Mode is used.
Yes: The STOP Mode parameters appear and you can select the STOP Mode. If you set the STOP
Mode to the same protocol as the RUN Mode, then the other STOP Mode parameters are read-
only and are set to the same values as for the RUN Mode.
Default: No.
STOP Mode
(Available only when Specify STOP Mode is set to Yes.)
The STOP Mode protocol to execute on the serial port. If you set the STOP Mode to the same
protocol as for the RUN Mode, then the other STOP Mode parameters are read-only and are set
to the same values as for the RUN Mode.
Choices and defaults are determined by the Port Mode setting.
■
SNP Slave: Reserved for the exclusive use of the SNP slave.
■
RTU Slave: Reserved for the exclusive use of the Modbus RTU Slave protocol.
If the STOP Mode protocol is different from the Port mode protocol, you can set parameters for
the STOP Mode protocol.
If you do not select a STOP Mode protocol, the default protocol with default parameter settings is
used.
Port (RUN) Mode STOP Mode
RTU Slave
Choices: SNP Slave, RTU Slave
Default: RTU Slave.
Message Mode
Choices: SNP Slave, RTU Slave
Default: RTU Slave.
Available
Available (Not supported on CPE305)
SNP Slave
SNP Slave
Serial I/O
Choices: SNP Slave, RTU Slave
Default: RTU Slave.
Note: Setting the Port Mode to RTU Slave and the STOP Mode to SNP Slave may cause loss of
programmer connection and delayed reconnection when the controller transitions from
STOP to RUN Mode. To avoid this behavior, select SNP Slave for the Port Mode and do not
specify a STOP Mode. For additional details, see RTU Slave/SNP Slave Operation with
Programmer Attached.
Documents you may be interested
Documents you may be interested
