SIEMENS s7-300 Compact CPUs – CPU 312C

S7-300 CPU 312Cs7-300 CPU 312C

  • The compact CPU with integral digital inputs/outputs
  • For small applications with increased processing performance requirements
  • With technological functions

SIMATIC Micro Memory Card required for operation of CPU.

Product No. / Product DescriptionCPU 312C Ordering data
6ES7312-5BF04-0AB0
SIMATIC S7-300, CPU 312C COMPACT CPU WITH MPI, 10 DI/6 DO, 2 FAST COUNTERS (10 KHZ), INTEGRATED 24V DC POWER SUPPLY, 64 KBYTE WORKING MEMORY, FRONT CONNECTOR (1 X 40PIN) AND MICRO MEMORY CARD REQUIRED

Application

The CPU 312C is the compact CPU for small-scale applications with demanding requirements regarding processing speed. Integrated digital inputs/outputs support direct interfacing with the process.

Other possible uses result from the integrated technological functions:

  • Counting
  • Frequency measurement
  • Period measurement
  • Pulse-width modulatio

Design

The CPU 312C is equipped with the following:

  • Microprocessor;
    the processor achieves a processing time of 100 ns per binary instruction.
  • Extensive memory;
    64 KB high-speed work memory (equals approx. 21 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 installation)
  • 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. Among these connections, one is always reserved for programming devices and another for OPs. The MPI makes it possible to set up a simple network with a maximum of 16 CPUs via “global data communication”.
  • Integrated inputs/outputs
    10 digital inputs (all for alarm processing) and 6 digital outputs are available to connect the process signals to the CPU 312C.

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:s7-300 CPU 312C

  • General;
    definition of the name, system ID and location ID
  • Startup;
    definition of the startup characteristics of the CPU and the monitoring time
  • Cycle/clock memory;
    specifying the maximum cycle time and loading, setting the clock memory address.
  • Retentivity;
    setting retentive areas
  • Time-of-day interrupts;
    setting of start date, start time and periodicity
  • Cyclic interrupts;
    setting of periodicity
  • System diagnostics;
    determining handling and scope of the diagnostic messages
  • Clock;
    setting the type of synchronization in the AS or on the MPI
  • Protection level;
    specifying the access rights to program and data
  • Communication;
    reservation of connection resources
  • MPI multi-point interface;
    determining station addresses
  • Digital inputs/outputs;
    setting of addresses, input delay and process interrupt
  • Integrated function “counting”;
    setting the addresses, parameter assignment of the modes “continuous counting”, “single counting”, “periodic counting”, “frequency measurement” and “pulse width modulation”

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)

Integrated functions

  • Counters;
    2 channels (up to 10 kHz) with directionally-dependent comparators and to directly connect 24 V incremental encoders
  • 2 channels for frequency measurement;
    frequency measurement (up to 10 kHz) enables, for example, measuring a shaft’s speed with speed range monitoring or throughput measuring (parts per measuring time) with range monitoring.
  • Period measurement;
    2 channels. The period duration of the counting signal can be measured up to a counting frequency of 1 kHz.
  • Pulse width modulation;
    2 outputs for direct control of valves, final controlling elements, switching devices, heating equipment, etc., switching frequency 2.5 kHz. The period length can be set and the pulse-pause ratio can be changed while running.
  • Alarm inputs (all digital inputs);
    the alarm inputs enable the detection of process events as well as the rapid triggering of responses.

Technical specifications

Article number

6ES7312-5BF04-0AB0

CPU312C, 10DI/6DO, 64 KB

General information

Hardware product version

01

Firmware version

V3.3

Engineering with

  • ● Programming package

STEP 7 V5.5 + SP1 or higher or STEP 7 V5.3 + SP2 or higher with HSP 203

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)

Miniature circuit breaker, type C; min. 2 A; miniature circuit breaker type B, min. 4 A

Mains buffering

  • ● Mains/voltage failure stored energy time

5 ms

  • ● Repeat rate, min.

1 s

Digital outputs

  • — Rated value (DC)

24 V

  • — Reverse polarity protection

No

Input current

Current consumption (rated value)

570 mA

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

90 mA

Inrush current, typ.

5 A

I²t

0.7 A²·s

Digital outputs

  • ● from load voltage L+, max.

25 mA

Power loss

Power loss, typ.

8 W

Memory

Work memory

  • ● integrated

64 kbyte

  • ● expandable

No

  • ● Size of retentive memory for retentive data blocks

64 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.

64 kbyte

FB

  • ● Number, max.

1 024; Number range: 0 to 7999

  • ● Size, max.

64 kbyte

FC

  • ● Number, max.

1 024; Number range: 0 to 7999

  • ● Size, max.

64 kbyte

OB

  • ● Description

see instruction list

  • ● Size, max.

64 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, max. 64 KB

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.

64 kbyte

  • ● Retentivity adjustable

Yes; via non-retain property on DB

  • ● Retentivity preset

Yes

Local data

  • ● per priority class, max.

32 kbyte; Max. 2048 bytes per block

Address area

I/O address area

  • ● Inputs

1 024 byte

  • ● Outputs

1 024 byte

of which distributed

  • — Inputs

none

  • — Outputs

none

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

Default addresses of the integrated channels

  • — Digital inputs

124.0 to 125.1

  • — Digital outputs

124.0 to 124.5

Digital channels

  • ● Inputs

266

  • — of which central

266

  • ● Outputs

262

  • — of which central

262

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

none

  • ● 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

10

  • ● of which inputs usable for technological functions

8

integrated channels (DI)

10

Input characteristic curve in accordance with IEC 61131, type 1

Yes

horizontal installation

  • — up to 40 °C, max.

10

  • — up to 60 °C, max.

5

vertical installation

  • — up to 40 °C, max.

5

Input voltage

  • ● Rated value (DC)

24 V

  • ● for signal “0”

-3 to +5V

  • ● for signal “1”

+15 to +30V

Input current

  • ● for signal “1”, typ.

8 mA

Input delay (for rated value of input voltage)

for standard inputs

  • — parameterizable

Yes; 0.1 / 0.3 / 3 / 15 ms (You can reconfigure the input delay of the standard inputs during program runtime. Please note that under certain circumstances your newly set filter time may not be effective until the next filter cycle.)

  • — Rated value

3 ms

for counter/technological functions

  • — at “0” to “1”, max.

48 µs; Minimum pulse width/minimum pause between pulses at maximum counting frequency

Cable length

  • ● shielded, max.

1 000 m; 100 m for technological functions

  • ● unshielded, max.

600 m; For technological functions: No

for technological functions

  • — shielded, max.

100 m; at maximum count frequency

  • — unshielded, max.

not allowed

Digital outputs

Number of digital outputs

6

  • ● of which high-speed outputs

2; Notice: You cannot connect the fast outputs of your CPU in parallel

integrated channels (DO)

6

Short-circuit protection

Yes; Clocked electronically

  • ● Response threshold, typ.

1 A

Limitation of inductive shutdown voltage to

L+ (-48 V)

Controlling a digital input

Yes

Switching capacity of the outputs

  • ● on lamp load, max.

5 W

Load resistance range

  • ● lower limit

48 Ω

  • ● upper limit

4 kΩ

Output voltage

  • ● for signal “1”, min.

L+ (-0.8 V)

Output current

  • ● for signal “1” rated value

500 mA

  • ● for signal “1” permissible range, min.

5 mA

  • ● for signal “1” permissible range, max.

0.6 A

  • ● for signal “1” minimum load current

5 mA

  • ● for signal “0” residual current, max.

0.5 mA

Parallel switching of two outputs

  • ● for uprating

No

  • ● for redundant control of a load

Yes

Switching frequency

  • ● with resistive load, max.

100 Hz

  • ● with inductive load, max.

0.5 Hz

  • ● on lamp load, max.

100 Hz

  • ● of the pulse outputs, with resistive load, max.

2.5 kHz

horizontal installation

  • — up to 40 °C, max.

2 A

  • — up to 60 °C, max.

1.5 A

vertical installation

  • — up to 40 °C, max.

1.5 A

Cable length

  • ● shielded, max.

1 000 m

  • ● unshielded, max.

600 m

Analog inputs

Number of analog inputs

0

integrated channels (AI)

0

Analog outputs

Number of analog outputs

0

integrated channels (AO)

0

Connectable encoders

  • ● 2-wire sensor

Yes

  • — permissible quiescent current (2-wire sensor), max.

1.5 mA

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; but via CP and loadable FB

  • — 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

Interrupts/diagnostics/status information

Diagnostics indication LED

  • ● Status indicator digital input (green)

Yes

  • ● Status indicator digital output (green)

Yes

Integrated Functions

Number of counters

2; See “Technological Functions” manual

Counting frequency (counter) max.

10 kHz

Frequency measurement

Yes

Number of frequency meters

2; up to 10 kHz (see “Technological Functions” manual)

controlled positioning

No

integrated function blocks (closed-loop control)

No

PID controller

No

Number of pulse outputs

2; Pulse width modulation up to 2.5 kHz (see “Technological Functions” Manual)

Limit frequency (pulse)

2.5 kHz

Potential separation

Potential separation digital inputs

  • ● Potential separation digital inputs

Yes

  • ● between the channels

No

  • ● between the channels and backplane bus

Yes

Potential separation digital outputs

  • ● Potential separation digital outputs

Yes

  • ● between the channels

No

  • ● between the channels and backplane bus

Yes

Isolation

Isolation tested with

600 V DC

Ambient conditions

Ambient temperature during operation

  • ● min.

0 °C

  • ● max.

60 °C

Configuration

Configuration software

  • ● STEP 7

Yes; STEP 7 V5.5 + SP1 or higher or STEP 7 V5.3 + SP2 or higher with HSP 203

  • ● STEP 7 Lite

No

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

80 mm

Height

125 mm

Depth

130 mm

Weights

Weight, approx.

410 g