9-8 ARRANCADORES PARA MOTORES DC
1. Proteger el motor contra daños debidos a cortocircuitos en el equipo 2. Proteger el motor contra daños por sobrecargas prolongadas
You can define a security level for your project in order to prevent unauthorized access to the CPU programs. The objective of these security settings is to grant a user access to specific PG functions which are not protected by password, and to allow this user to execute these functions on the CPU. When logged on with password, the user may execute all PG functions.
Setting security levels
You can set the CPU security levels 1 to 3 in STEP 7 under Configure Hardware. If you do not know the password, you can clear the security setting by means of a manual CPU memory reset using the mode selector switch. The CPU may not contain a Flash card when you perform such an operation.
Table 4-3 lists the security levels of an S7-400 CPU.
Table 4-3 CPU security levels
CPU function Security level 1 Security level 2 Security level 3
Visualization of the block list Access granted Access granted Access granted Monitoring tags Access granted Access granted Access granted Module status STACKS Access granted Access granted Access granted Control and monitoring
functions Access granted Access granted Access granted S7 communication Access granted Access granted Access granted Reading the time Access granted Access granted Access granted Setting the time Access granted Access granted Access granted Status block Access granted Access granted Password
required Upload to PG Access granted Access granted Password
required Download to CPU Access granted Password
required
Password required Deleting blocks Access granted Password
required Passwordrequired Compressing memory Access granted Password
required Passwordrequired Download of the user
program to a Memory Card Access granted Passwordrequired Passwordrequired Controlling selection Access granted Password
required Passwordrequired Controlling tags Access granted Password
required Passwordrequired
Breakpoint Access granted Password
required Passwordrequired Clear breakpoint Access granted Password
required
Password required
Table 4-3 CPU security levels, continued
CPU function Security level 1 Security level 2 Security level 3
Memory Reset Access granted Password
required Passwordrequired
Force Access granted Password
required Passwordrequired
4.7
Operating Sequence for Memory Reset
Use case A: You want to download a new user program to the CPU.
1. Set the switch to STOP position.
Result: The STOP LED is lit.
2. Toggle the switch to MRES, and hold it in this position. This selector switch position has a pushbutton action contact.
Result: The STOP LED is dark for a second, light for a second, dark for a
second and then remains on.
3. Release the switch, return it to MRES within the next three seconds, and then release it again.
Result: The STOP LED flashes for a duration of at least 3 seconds at 2 Hz
(CPU memory reset is being executed), and then lights up continuously
Use case B: The STOP LED flashing slowly at 0.5 Hz indicates that the CPU is requesting a memory reset (system memory reset request, after a memory card has been removed or inserted, for example).
Toggle the switch to MRES, and then release it again.
Result: The STOP LED flashes for a duration of at least 3 seconds at 2 Hz
while the CPU memory reset is being executed, and then the LED lights up continuously.
Sequence of a CPU memory reset
Sequence of the CPU for a memory reset: • The CPU deletes the user program from RAM.
• The CPU deletes the user program from load memory. This process deletes the program from the on--board RAM and from any RAM Card. The user program elements stored on Flash card will not be deleted if you have expanded load memory with such a card.
• The CPU resets all counters. flags and timers, but not the time--of--day. • The CPU tests its hardware.
• The CPU sets its parameters to default values.
• When a FLASH Card is inserted, the CPU continues after its memory reset by copying the user program and the system parameters from the Flash card to
Data retained after a CPU memory reset...
The following values are retained after a CPU memory reset: • The content of the diagnostics buffer
If you had not inserted a flash card during CPU memory reset, the CPU resets the capacity of the diagnostics buffers to its default setting of 120 entries, i.e. the most recent 120 entries will be retained in the diagnostics buffer.
You can read the content of the diagnostics buffer using STEP 7.
• The MPI interface parameters. These define the MPI address and the highest MPI address. Note the special features shown in the table below.
• The time
• The status and value of the operating hours counter
Special feature: MPI parameters
The MPI parameters take an exceptional position during CPU memory reset. The table below lists the MPI parameter which are valid after a CPU memory reset.
CPU memory Reset MPI parameters...
with inserted FLASH Card ...stored on the FLASH Card are valid without inserted FLASH Card ...in the CPU are retained and thus valid
Cold restart
• A cold restart initializes the process image, all flags, timers, counters and data blocks with the start values stored in load memory, regardless whether these data were configured as being retentive or not.
• Program execution resumes with OB1, or with OB102.
Restart (warm restart)
• A warn restart resets the process image and the non--retentive flags, timers and counters.
Retentive flags, timers, counters and all data blocks retain their last valid value. • Program execution resumes with OB1, or with OB101.
• A warm restart after power failure is only possible if memory is backed up.
Operating sequence for restart t/warm restart
1. Set the switch to STOP position.
Result: The STOP LED lights up.
2. Set the switch to RUN position.
Result: The STOP LED is dark, the RUN LED is lit.
Whether the CPU performs a restart or a hot restart is determined by its configuration.
Operating sequence for cold restart
A cold start is always initiated using the PG command “Cold start”. To do so, the CPU must be in STOP, and the mode selector switch must be set to RUN.
4.8
Expanding Load Memory with Memory Cards
Order Numbers
The order numbers for memory cards are listed in the technical data at the end of this chapter.
Design of a Memory Card
The size of a Memory Card corresponds with that of a PCMCIA card. It is inserted into a front--panel slot of the CPU.
Grip
Side elevation
Type plate with serial number, e.g. SVP N4 1492 15 Front elevation Nam e of the M em or y C ar d Or der N um ber
Figure 4-3 Design of the memory card
Function of the Memory Card
The memory card and an integrated memory section on the CPU together form the loading memory of the CPU. During operation, the loading memory contains the complete user program, including the comments, the symbols and special
additional information that enables back-translation of the user program as well as all module parameters.
Data stored on Memory Card
The following data can be stored on Memory Card:
• The user program, i.e. the OBs, FBs, FCs, DBs and system data • Parameters that determine the behavior of the CPU
• Parameters that determine the behavior of the I/O modules. • As of STEP 7 V5.1, all project files on suitable Memory Cards.
Types of Memory Cards for the S7-400
Two types of memory card are used for the S7-400: • RAM cards
• Flash cards (FEPROM cards)
Note
Memory cards unknown to the system can not be used in the S7-400.
Which type of Memory Card to use
Whether you use a RAM card or a Flash card depends on your application.
Table 4-4 Types of memory cards
If you ... ...Then
also want to be able to edit your program in
RUN, use a RAM card
want to keep a permanent backup of your user program on Memory Card when power is off, i.e. without backup battery or outside the CPU,
use a Flash card
RAM Card
Insert the RAM Card for the download of the user program to the CPU. Download the user program in STEP 7 by selecting “PLC --> Download user program to Memory Card”.
You can download the entire user program or the separate elements such as FBs, FCs, OBs, DBs, or SDBs to load memory in STOP or in RUN.
When you remove the RAM card from the CPU, the information stored on it will be lost. The RAM card is not equipped with an integrated backup battery.
If the power supply is equipped with an operational backup battery, or the CPU is supplied with an external backup voltage at the ”EXT. BATT.” input, the RAM Card contents are retained when power is switched off, provided the RAM card remains inserted in the CPU and the CPU remains inserted in the rack.
FLASH Card
If you use a Flash card, there are two ways of loading the user program:
• Use the mode selector switch to set the CPU to STOP. Insert the FLASH Card into the CPU, and then download the suer program in STEP 7 to the Flash card by selecting “PLC --> Download user program to Memory Card”.
• Load the user program into the Flash card in offline mode at the programming device/programming adapter, and then insert the Flash card into the CPU. The FLASH card is a non--volatile memory, i.e. its data are retained when the it is removed from the CPU or your S7-400 is being operated without backup voltage (without a backup battery in the power supply module or external backup voltage at the ”EXT. BATT.” input of the CPU).
You always download the full user program to a FLASH Card.
Downloading additional user program elements
You can download further elements of the user program from the PG to the integrated load memory of the CPU. Note that the content of this memory area will be deleted if the CPU performs a memory reset, i.e. load memory is updated with the user program stored on Memory Card after a CPU memory reset.
Memory Card capacity requirements
Determining Memory Requirements using SIMATIC Manager
You can view the block lengths offline by selecting the “Properties - Block folder offline” dialog box (Blocks --> Object Properties --> Blocks tab).
The offline view shows the following lengths:
• Size (sum of all blocks, without system data) in load memory of the PLC • Size (sum of all blocks, without system data) in RAM of the PLC
Block lengths from the engineering device (PG/PC) are not shown in the properties of the block container.
Block lengths are shown in ”byte” units.
The following values are shown in the block properties: • Required local data volume: length of local data in bytes • MC7: length of the MC7 code in bytes
• Length of DB user data
• Length in load memory of the PLC
• Lengths in RAM of the PLC (only if hardware assignment is known.)
The views always show these block data, regardless whether it is located in the window of an online view or of an offline view..
When a block container is opened and ”View Details” is set, the project view always indicates RAM requirements, regardless whether the block container appears in the window of an online or offline view.
You can add up the block lengths by selecting all relevant blocks. SIMATIC Manager outputs the total length of the selected blocks in its status bar.
The view does not indicate the lengths of blocks (VATs, for example) which can not be downloaded to the PLC.
Block lengths on the engineering system (PG/PC) are not shown in the Details view.
Technical data
Name Order number Current
consumption at 5 V Backupcurrents
MC 952 / 256 KB / RAM 6ES7 952-1AH00-0AA0 typ. 35 mA
max. 80 mA typ. 1 μΑmax. 40 μA MC 952 / 1 MB / RAM 6ES7 952-1AK00-0AA0 typ. 40 mA
Max. 90 mA typ. 3 μAmax. 50 μA MC 952 / 2 MB / RAM 6ES7 952-1AL00-0AA0 typ. 45 mA
max. 100 mA
typ. 5 μA max. 60 μA MC 952 / 4 MB / RAM 6ES7 952-1AM00-0AA0 typ. 45 mA
max. 100 mA
typ. 5 μA max. 60 μA MC 952 / 8 MB / RAM 6ES7 952-1AP00-0AA0 typ. 45 mA
max. 100 mA typ. 5 μAmax. 60 μA MC 952 / 16 MB / RAM 6ES7 952-1AS00-0AA0 typ. 45 mA
max. 100 mA typ. 5 μAmax. 60 μA MC 952 / 1 MB / 5--V Flash 6ES7 952-1KK00-0AA0 typ. 40 mA
Max. 90 mA
-- MC 952 / 2 MB / 5--V Flash 6ES7 952-1KL00-0AA0 typ. 50 mA
max. 100 mA
-- MC 952 / 4 MB / 5--V Flash 6ES7 952-1KM00-0AA0 typ. 40 mA
Max. 90 mA
-- MC 952 / 8 MB / 5--V Flash 6ES7 952-1KP00-0AA0 typ. 50 mA
max. 100 mA
-- MC 952 / 16 MB / 5V Flash 6ES7 952-1KS00-0AA0 typ. 55 mA
max. 110 mA
-- MC 952 / 32 MB / 5--V Flash 6ES7 952-1KT00-0AA0 typ. 55 mA
max. 110 mA
-- MC 952 / 64 MB / 5--V Flash 6ES7 952-1KY00-0AA0 typ. 55 mA
max. 110 mA
--
Dimensions W¢H¢D (in mm) 7.5 ¢ 57 ¢ 87
Weight max. 35 g