CPU 312 – the smallest SIEMENS SIMATIC S7-300 CPU

Overview

  • The entry level CPU in Totally Integrated Automation (TIA)
  • For smaller applications with moderate processing performance requirements

SIMATIC Micro Memory Card required for operation of the CPU.

Product No. / Product DescriptionS7-300 CPU 312 Ordering data
6ES7312-1AE14-0AB0
SIMATIC S7-300, CPU 312 CPU WITH MPI INTERFACE, INTEGRATED 24 V DC POWER SUPPLY 32 KBYTE WORKING MEMORY, MICRO MEMORY CARD NECESSARY

Application

CPU 312, the smallest S7-300 CPU. This is ideally suited to simple applications in which the advantages of TIA such as integrated communication, data management and diagnostics can however be utilized. Networking is possible using MPI or by means of CPs, the standard mode of application is, however, non-networked operation. The I/O is normally connected in a centralized configuration.


DesignS7-300 CPU 312

The CPU 312 is equipped with the following:

  • Microprocessor;
    the processor achieves a processing time of 100 ns per binary instruction.
  • Extensive memory;
    32 KB high-speed RAM (equals approx. 10 K instructions) for program components relevant to execution offers sufficient space for user programs;
    SIMATIC Micro Memory Cards (max. 8 MB) as load memory for the program also allow the project to be stored in the CPU (complete with symbols and comments).
  • Flexible expansion capability
    max. 8 modules (1-tier configuration)
  • MPI multi-point interface
    The integrated MPI interface can establish as many as 6 connections simultaneously to S7-300/400 or to programming device, PC, OP. One of these connections is always reserved for the PG and another one for the OP. The MPI makes it possible to set up a simple network with a maximum of 16 CPUs via “global data communication”.

Function

  • Password protection;
    a password concept protects the user program from unauthorized access.
  • Block encryption;
    the functions (FCs) and function blocks (FBs) can be stored in the CPU in encrypted form by means of S7-Block Privacy to protect the know-how of the application.
  • Diagnostics buffer;
    the last 500 error and interrupt events are stored in a buffer for diagnostic purposes, of which 100 are stored retentively.
  • Maintenance-free data backup;
    retentive data is automatically backed up by the CPU if the voltage is interrupted and is available unchanged after the voltage has been reconnected.

Parameterizable properties

The S7 configuration as well as the properties and response of the CPUs can be parameterized using STEP 7:

  • General;
    definition of the name, plant identifier and location ID. Parameter assignment of the multi-point interface MPI: Determining node addresses
  • Startup;
    definition of the startup characteristics of the CPU and the monitoring time
  • Cycle/clock memory;
    specification of the maximum cycle time and load. Setting of the clock memory address.
  • Retentivity;
    definition of the number of retentive bit memories, counters, timers and data blocks
  • Clock interrupts;
    setting of start date, start time and periodicity
  • Watchdog interrupts;
    setting of periodicity
  • System diagnostics;
    determining handling and scope of the diagnostic alarms
  • Clock;
    setting of the synchronization method in the AS or on the MP
  • Protection level;
    specifying the access rights to program and data
  • Communication;
    reservation of connection resources

Display and information functions

  • Status and error indications;
    LEDs indicate e.g. hardware, programming, time or I/O errors, as well as operating states such as RUN, STOP and start-up.
  • Test functions;
    the PG is used to indicate signal states during program execution, to modify process variables independently of the user program and to output the contents of stack memories.
  • Information functions;
    you can use the PG to obtain information about the storage capacity and operating mode of the CPU as well as the current loading of the main and load memories as well as current cycle times and diagnostic buffer contents in plain text.

Integrated communication functions

  • PG/OP communication
  • Global data communication
  • S7 basic communication
  • S7 communication (server only)

System functions

The CPU provides many extensive system functions for diagnostics, parameterization, synchronization, alerting, time measurement, etc.

For detailed information, refer to the manual.


Technical specifications

Article number

6ES7312-1AE14-0AB0

CPU312, 32KB

General information

Hardware product version

01

Firmware version

V3.3

Engineering with

  • ● Programming package

STEP 7 V5.5 + SP1 or higher or STEP 7 V5.2 + SP1 or higher with HSP 218

Supply voltage

Rated value (DC)

  • ● 24 V DC

Yes

permissible range, lower limit (DC)

19.2 V

permissible range, upper limit (DC)

28.8 V

external protection for power supply lines (recommendation)

2 A min.

Mains buffering

  • ● Mains/voltage failure stored energy time

5 ms

  • ● Repeat rate, min.

1 s

Input current

Current consumption (rated value)

650 mA

Current consumption (in no-load operation), typ.

140 mA

Inrush current, typ.

3.5 A

I²t

1 A²·s

Power loss

Power loss, typ.

4 W

Memory

Work memory

  • ● integrated

32 kbyte

  • ● expandable

No

  • ● Size of retentive memory for retentive data blocks

32 kbyte

Load memory

  • ● Plug-in (MMC)

Yes

  • ● Plug-in (MMC), max.

8 Mbyte

  • ● Data management on MMC (after last programming), min.

10 y

Backup

  • ● present

Yes; Guaranteed by MMC (maintenance-free)

  • ● without battery

Yes; Program and data

CPU processing times

for bit operations, typ.

0.1 µs

for word operations, typ.

0.24 µs

for fixed point arithmetic, typ.

0.32 µs

for floating point arithmetic, typ.

1.1 µs

CPU-blocks

Number of blocks (total)

1 024; (DBs, FCs, FBs); the maximum number of loadable blocks can be reduced by the MMC used.

DB

  • ● Number, max.

1 024; Number range: 1 to 16000

  • ● Size, max.

32 kbyte

FB

  • ● Number, max.

1 024; Number range: 0 to 7999

  • ● Size, max.

32 kbyte

FC

  • ● Number, max.

1 024; Number range: 0 to 7999

  • ● Size, max.

32 kbyte

OB

  • ● Description

see instruction list

  • ● Size, max.

32 kbyte

  • ● Number of free cycle OBs

1; OB 1

  • ● Number of time alarm OBs

1; OB 10

  • ● Number of delay alarm OBs

2; OB 20, 21

  • ● Number of cyclic interrupt OBs

4; OB 32, 33, 34, 35

  • ● Number of process alarm OBs

1; OB 40

  • ● Number of startup OBs

1; OB 100

  • ● Number of asynchronous error OBs

4; OB 80, 82, 85, 87

  • ● Number of synchronous error OBs

2; OB 121, 122

Nesting depth

  • ● per priority class

16

  • ● additional within an error OB

4

Counters, timers and their retentivity

S7 counter

  • ● Number

256

Retentivity

  • — adjustable

Yes

  • — lower limit

0

  • — upper limit

255

  • — preset

Z 0 to Z 7

Counting range

  • — lower limit

0

  • — upper limit

999

IEC counter

  • ● Number

Unlimited (limited only by RAM capacity)

S7 times

  • ● Number

256

Retentivity

  • — adjustable

Yes

  • — lower limit

0

  • — upper limit

255

  • — preset

No retentivity

Time range

  • — lower limit

10 ms

  • — upper limit

9 990 s

IEC timer

  • ● present

Yes

  • ● Type

SFB

  • ● Number

Unlimited (limited only by RAM capacity)

Data areas and their retentivity

retentive data area in total

All (incl. memory bits, times, counters)

Flag

  • ● Number, max.

256 byte

  • ● Retentivity available

Yes; MB 0 to MB 255

  • ● Retentivity preset

MB 0 to MB 15

  • ● Number of clock memories

8; 1 memory byte

Data blocks

  • ● Number, max.

1 024; Number range: 1 to 16000

  • ● Size, max.

32 kbyte

  • ● Retentivity adjustable

Yes; via non-retain property on DB

  • ● Retentivity preset

Yes

Local data

  • ● per priority class, max.

32 kbyte; Max. 2 KB per block

Address area

I/O address area

  • ● Inputs

1 024 byte

  • ● Outputs

1 024 byte

Process image

  • ● Inputs

1 024 byte

  • ● Outputs

1 024 byte

  • ● Inputs, adjustable

1 024 byte

  • ● Outputs, adjustable

1 024 byte

  • ● Inputs, default

128 byte

  • ● Outputs, default

128 byte

Digital channels

  • ● Inputs

256

  • — of which central

256

  • ● Outputs

256

  • — of which central

256

Analog channels

  • ● Inputs

64

  • — of which central

64

  • ● Outputs

64

  • — of which central

64

Hardware configuration

Number of expansion units, max.

0

Number of DP masters

  • ● integrated

0

  • ● via CP

4

Number of operable FMs and CPs (recommended)

  • ● FM

8

  • ● CP, PtP

8

  • ● CP, LAN

4

Rack

  • ● Racks, max.

1

  • ● Modules per rack, max.

8

Time of day

Clock

  • ● Software clock

Yes

  • ● retentive and synchronizable

No; Buffered: No, Can be synchronized: Yes

  • ● Deviation per day, max.

10 s; Typ.: 2 s

  • ● Behavior of the clock following POWER-ON

The clock continues at the time of day it had when power was switched off

Operating hours counter

  • ● Number

1

  • ● Number/Number range

0

  • ● Range of values

0 to 2^31 hours (when using SFC 101)

  • ● Granularity

1 hour

  • ● retentive

Yes; Must be restarted at each restart

Clock synchronization

  • ● supported

Yes

  • ● to MPI, master

Yes

  • ● to MPI, slave

Yes

  • ● in AS, master

Yes

  • ● in AS, slave

No

Digital inputs

Number of digital inputs

0

Digital outputs

Number of digital outputs

0

Analog inputs

Number of analog inputs

0

Analog outputs

Number of analog outputs

0

Interfaces

Number of industrial Ethernet interfaces

0

Number of RS 485 interfaces

1; MPI

Number of RS 422 interfaces

0

1. Interface

Interface type

Integrated RS 485 interface

Physics

RS 485

Isolated

No

Power supply to interface (15 to 30 V DC), max.

200 mA

Functionality

  • ● MPI

Yes

  • ● PROFIBUS DP master

No

  • ● PROFIBUS DP slave

No

  • ● Point-to-point connection

No

MPI

  • ● Transmission rate, max.

187.5 kbit/s

Services

  • — PG/OP communication

Yes

  • — Routing

No

  • — Global data communication

Yes

  • — S7 basic communication

Yes

  • — S7 communication

Yes; Only server, configured on one side

  • — S7 communication, as client

No

  • — S7 communication, as server

Yes

Communication functions

PG/OP communication

Yes

Data record routing

No

Global data communication

  • ● supported

Yes

  • ● Number of GD loops, max.

8

  • ● Number of GD packets, max.

8

  • ● Number of GD packets, transmitter, max.

8

  • ● Number of GD packets, receiver, max.

8

  • ● Size of GD packets, max.

22 byte

  • ● Size of GD packet (of which consistent), max.

22 byte

S7 basic communication

  • ● supported

Yes

  • ● User data per job, max.

76 byte

  • ● User data per job (of which consistent), max.

76 byte; 76 bytes (with X_SEND or X_RCV); 64 bytes (with X_PUT or X_GET as server)

S7 communication

  • ● supported

Yes

  • ● as server

Yes

  • ● as client

Yes; Via CP and loadable FB

  • ● User data per job, max.

180 byte; With PUT/GET

  • ● User data per job (of which consistent), max.

240 byte; as server

S5 compatible communication

  • ● supported

Yes; via CP and loadable FC

Number of connections

  • ● overall

6

  • ● usable for PG communication

5

  • — reserved for PG communication

1

  • — adjustable for PG communication, min.

1

  • — adjustable for PG communication, max.

5

  • ● usable for OP communication

5

  • — reserved for OP communication

1

  • — adjustable for OP communication, min.

1

  • — adjustable for OP communication, max.

5

  • ● usable for S7 basic communication

2

  • — reserved for S7 basic communication

0

  • — adjustable for S7 basic communication, min.

0

  • — adjustable for S7 basic communication, max.

2

S7 message functions

Number of login stations for message functions, max.

6; Depending on the configured connections for PG/OP and S7 basic communication

Process diagnostic messages

Yes

simultaneously active Alarm-S blocks, max.

300

Test commissioning functions

Status block

Yes; Up to 2 simultaneously

Single step

Yes

Number of breakpoints

4

Status/control

  • ● Status/control variable

Yes

  • ● Variables

Inputs, outputs, memory bits, DB, times, counters

  • ● Number of variables, max.

30

  • — of which status variables, max.

30

  • — of which control variables, max.

14

Forcing

  • ● Forcing

Yes

  • ● Forcing, variables

Inputs, outputs

  • ● Number of variables, max.

10

Diagnostic buffer

  • ● present

Yes

  • ● Number of entries, max.

500

  • — adjustable

No

  • — of which powerfail-proof

100; Only the last 100 entries are retained

  • ● Number of entries readable in RUN, max.

499

  • — can be set

Yes; From 10 to 499

  • — preset

10

Service data

  • ● can be read out

Yes

Ambient conditions

Ambient temperature during operation

  • ● min.

0 °C

  • ● max.

60 °C

Configuration

Configuration software

  • ● STEP 7

Yes; V5.2 SP1 or higher with HW update

Programming

  • ● Command set

see instruction list

  • ● Nesting levels

8

  • ● System functions (SFC)

see instruction list

  • ● System function blocks (SFB)

see instruction list

Programming language

  • — LAD

Yes

  • — FBD

Yes

  • — STL

Yes

  • — SCL

Yes

  • — GRAPH

Yes

  • — HiGraph®

Yes

Know-how protection

  • ● User program protection/password protection

Yes

  • ● Block encryption

Yes; With S7 block Privacy

Dimensions

Width

40 mm

Height

125 mm

Depth

130 mm

Weights

Weight, approx.

270 g