Siemens Simatic s5 User manual

SIMATIC S5

Standard Function Counter

for the IP 265

Manual

EWA 4NEB 812 6131-02a

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EWA 4NEB 811 6131-02

Standard Function Counter Preface

Preface

Counting of high-speed processes is an essential task in automation. For this reason, SIEMENS

offers a submodule with the standard function counter, MLFB 6ES5 840-4SH01.

The submodule with the standard function counter can be used together with an IP 265 in the S5-

90U, S5-95U and S5-100U programmable controllers and additionally in the ET 200 system (from

version Z02 of the IM 318-B).

The principle of operation of the IP 265 is determined by the use of the submodule with the standard

function counter.

All interfaces to the standard function are the interfaces of the IP 265 to the SIMATIC environment

or to the process I/O.

See the relevant section of your system manual for details of the construction of a system or the

installation of the module.

Function overview of the standard function

Three different counter functions have been stored in the submodule. The functions can be divided

into two areas:

• 2 counters with 16-bit data width

These two counters can be used independently of one another as up counter (normal counter

function) or as down counter (periodic counter function).

• 1 counter with 32-bit data width

Both counters can be combined into one 32-bit wide counter (cascade function) for counter

functions requiring a considerably larger data area. This counter operates as a down counter

(like the periodic counter function).

From the STEP 5 program, you can set the relevant setpoints and control signals and read the

relevant actual values and diagnostic signals over the I/O bus.

The following description refers exclusively to the principle of operation of the standard function

counter in the IP 265.

Please see the descriptions in the IP 265 manual or in your system manual (S5-95U, S5-100U) for

details of installation guidelines and connection methods.

Convention

Information of special importance is contained in framed boxes like the following:

Warning / Note

See the Safety-Related Guidelines in your manual (IP 265) or your system manual (S5-95U) for the

definition of the terms "Warning" and "Note".

EWA 4NEB 812 6131-02 iii

Standard Function Counter Contents

Contents

Page

1 Construction of the IP 265 Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 1

1.1 Hardware design of the module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 1

1.1.1 Terminal for Load Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 1

1.1.2 Digital 24 V Inputs/Digital 24 V Outputs . . . . . . . . . . . . . . . . . . . . . . . . 1 - 2

1.1.3 Symmetrical 5 V Differential Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 3

1.1.4 Submodule Receptacle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 4

1.1.5 LED Displays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 4

2 Installation Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 1

2.1 24 V DC Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 1

2.2 Establishing the Connection to the S5-100U Bus . . . . . . . . . . . . . . . . . 2 - 1

2.3 Establishing the Connection to the I/O . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 2

2.4 Further Notes on Configuring and Installing the Module . . . . . . . . . . . . . 2 - 4

3 Input and Output Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 1

3.1 Counter Pulses at the CU1 and CU2 Input . . . . . . . . . . . . . . . . . . . . . 3 - 1

3.2 Signals that have an Influence on Counting . . . . . . . . . . . . . . . . . . . . . 3 - 2

3.2.1 Resetting an Output (RSQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 2

3.2.2 Resetting a Counter Channel (RSC) . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 2

3.2.3 GATE Signal (GATE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 2

3.3 Counter Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 2

3.4 Location of the Signals in the Process I/O Images . . . . . . . . . . . . . . . . 3 - 3

3.5 ORing and Evaluating Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 3

EWA 4NEB 812 6131-02 v

Contents Standard Function Counter

Page

4 The Counter Functions 4 - 1

4.1 Selecting the Counter Function Mode . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 2

4.2 Transferring the Set Function Mode Using the IP 265 . . . . . . . . . . . . . . 4 - 3

4.2.1 Switching from Two-Channel Mode to Cascade Mode . . . . . . . . . . . . . 4 - 3

4.2.2 Switching from the Cascade Function to Two-Channel Mode . . . . . . . . . 4 - 3

4.3 Counter Statuses and Signal Flow in the Three Function Modes . . . . . . 4 - 4

4.3.1 The Normal Counter Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 4

4.3.2 The Periodic Counter Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 5

4.3.3 The Cascade Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 6

4.4 Value Range for Setpoints and Counter Values . . . . . . . . . . . . . . . . . . 4 - 7

4.5 Loading the setpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 7

4.5.1 Specifying and Implementing a Setpoint . . . . . . . . . . . . . . . . . . . . . . . 4 - 8

5 Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 1

6 Loading and Starting the Standard Function . . . . . . . . . . . . . . . . . . . . . . . 6 - 1

A Diagnostics and Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A - 1

A.1 Status Word (Byte 0, Byte 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A - 1

A.2 LED Displays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A - 1

B Technical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B - 1

C Ordering Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C - 1

vi EWA 4NEB 812 6131-02

Standard Function Counter Construction of the IP 265 Module

1 Construction of the IP 265 Module

1.1 Hardware design of the module

The standard function counter is carried by the IP 265, a single-width module of the S5-100 PLC.

The IP 265 is equipped with several hardware interfaces for communication with the system

environment.

Figure 1-1 shows the position of the interfaces and the operator controls on the frontplate of the

module.

Figure 1-1. Overview of the Module

a

6ES5 265-

8MA01

6

a

I

a

O

a

I

N

P

U

T

a

O

U

T

P

U

T

a

I

N

T

E

R

F

A

C

E

a

STOP RUN

1 2 3

a

HIGH

SPEED

SUB

CONTROL

a

L+

24 V

M

a

Digital outputs

(24 V)

Digital inputs

(24 V)

Memory submo-

dule receptacle

9-pin sub D

Submodule with standard

function counter

a

Operator controls on the frontplate

15-pin sub DDifferential inputs

(5 V)

Connector for

24 V load

voltage

2-pin connector

LEDsFault and status

displays

1.1.1 Terminal for Load Voltage

The load circuit of the plant controller is supplied with 24 V DC via the load voltage connector on the

frontplate of the IP 265.

The 24 V supply allows connection of 24 V plant sensors and actuators to the digital inputs and

outputs of the module (load current circuit).

Note

The IP 265 must receive the 24 V supply for operation.

EWA 4NEB 812 6131-02a 1-1

Construction of the IP 265 Module Standard Function Counter

1.1.2 Digital 24 V Inputs/Digital 24 V Outputs

Two 9-pin sub D interfaces are located on the frontplate of the IP 265

Connect the signal lines of the sensors to the 9-pin sub D connector marked "INPUT". You can

connect up to 8 24 V digital inputs. The frequency of the input signals may be up to 10 kHz.

Connect the signal lines of the actuators to the 9-pin sub D socket marked "OUTPUT". The

response time of the 24 V digital outputs depends on the resistive load of the output circuit and the

type of output level changes (LOW -> HIGH or HIGH -> LOW; see also the Technical

Specifications). A typical response time with maximum resistive load is 70 s.

See the following diagram for the pin assignments of both interfaces.

Figure 1-2. Pin Assignments of the Input Interface and the Output Interface

a

I

N

P

U

T

a

1

2

3

4

5

a

6

7

8

9

Meaning of the digital inputs

3

2

1

4

5

6

7

8

9

a

RSQ 1 reset output Q1

CU1 counter pulses channel 1

GATE 1 GATE signal channel 1

RSC 1 reset counter 1

CU2 counter pulses channel 2

GATE 2 GATE signal channel 2

RSQ reset output Q2

RSC 2 reset counter 2

Ground (24 V)

a

5

4

3

2

1

a

9

8

7

6

Meaning of the digital outputs

3

2

1

4

5

6

7

8

9

a

Q2 output channel 2

Q1 output channel 1

Q1\ negated output channel 1

Q2\ negated channel 2

---

Ground (24 V)

a

O

U

T

P

U

T

a

6ES5 265-

8MA01

6

a

I

a

O

a

I

N

P

U

T

a

O

U

T

P

U

T

a

I

N

T

E

R

F

A

C

E

a

STOP RUN

1 2 3

a

HIGH

SPEED

SUB

CONTROL

a

L+

24 V

M

a

1-2 EWA 4NEB 812 6131-02a

Standard Function Counter Construction of the IP 265 Module

1.1.3 Symmetrical 5 V Differential Inputs

The differential inputs are located on the 15-pin sub D socket of the module. The differential inputs

interface conforms to the RS422A standard. You can connect 5 V sensors with differential signals to

the differential inputs. Maximum input frequency is 58 kHz. The pulse length of the input signals at

the 5 V differential inputs (signal ”0” (0 V) or ”1” (5 V) must be at least 8.6 µs.

Unwired (”open”) 5 V differential inputs are handled by the IP 265 as differential inputs with signal

state ”1” (5 V).

Figure 1-3 shows you where on the 15-pin sub D socket the signal lines of the 5 V sensors are to

be connected. Four pins are reserved on the sub D socket for the two differential inputs. The

remaining 10 pins of the 15-pin sub D socket are irrelevant to the use of the counter function (->

see the IP 265 Manual for further information on the pin assignments of the interface).

Figure 1-3. Pin Assignments for the 5 V Differential Inputs

Meaning

1

2

a

A CU1

A-N Counter pulse channel 1

a

I

N

T

E

R

F

A

C

E

a

1

2

3

4

5

a

6

7

8

9

10

a

11

12

13

14

15

3 ... 5 irrelevant

6

7

9 ...

15 Irrelevant for the standard function

counter

8

a

6ES5 265-

8MA01

6

a

I

a

O

a

I

N

P

U

T

a

O

U

T

P

U

T

a

I

N

T

E

R

F

A

C

E

a

STOP RUN

1 2 3

a

HIGH

SPEED

SUB

CONTROL

a

L+

24 V

M

a

B CU2

B-N Counter pulse channel 2

Ground (5 V)

a

!Warning

All pins not used for the standard function counter must remain inactive.

EWA 4NEB 812 6131-02a 1-3

Construction of the IP 265 Module Standard Function Counter

1.1.4 Submodule Receptacle

The submodule with the standard function counter is plugged into the submodule receptacle on the

IP 265.

!Warning

The memory submodule can only be plugged in or removed when the module is in the

POWER OFF state.

1.1.5 LED Displays

The frontplate of the IP 265 is equipped with several LEDs:

• 1 red STOP LED

• 1 green RUN LED

• 8 green LEDs for 8 digital 24 V inputs

• 8 green LEDs for 8 digital 24 V outputs

Either the RUN LED or the STOP LED will light up to indicate the operating state of the IP 265.

Faults in the IP 265 are indicated by the STOP LED or by a combination of the RUN and the STOP

LED. Different faults are indicated by different flashing signals. See Appendix A for a summary of all

the possible status displays of the IP 265 in conjunction with the standard function counter.

1-4 EWA 4NEB 812 6131-02a

Standard Function Counter Installation Guidelines

2 Installation Guidelines

This section describes how to establish the connections with the programmable controller and the

process I/O.

2.1 24 V DC Supply

The IP 265 is a non-floating module. The 24 V DC load current circuits share the same ground with

the control circuit of the PLC.

Figure 2-1 shows the simplified connection of the IP 265 to the PLC.

Figure 2-1. Simplified Representation for Non-Floating Connection of the IP 265 to the PLC

a

L+

M

External power supply

Central ground

CPU

L+ M

L+

M

IP

Connector for

load voltage

Note

When using the IP 265, you must connect the ground of the IP 265 load voltage con-

nector with the CPU ground via an external connection at the central grounding point.

When doing so, please make sure you use a low-resistance connecting cable (cable

should be as short as possible).

2.2 Establishing the Connection to the S5-100U Bus

The IP 265 is like an I/O module of the S5-100U system and is snapped onto a bus unit. You must

note the following points when assembling and dismantling the module:

• The IP 265 may be plugged in or removed only without load voltage and when the CPU is in the

STOP state.

• The memory submodule may be plugged in or removed only when the module and the CPU are

in the POWER OFF state.

• The IP 265 can only be snapped onto a bus unit in slots 0 to 7 of the programmable controllers.

• For instructions on assembling and dismantling the module, see the IP 265 Manual or the

System Manuals for the S5-100U, S5 90/95U or ET 200.

EWA 4NEB 812 6131-02 2-1

Installation Guidelines Standard Function Counter

2.3 Establishing the Connection to the I/O

The following electrical connection must be made depending on your application:

• Connection between 24 V digital inputs of the module and plant sensors

• Connection between 24 V digital outputs of the module and plant actuators

• Connection between differential inputs of the module and sensors with differential signals

• 24 V power supply

Connecting 24 V digital inputs

The digital inputs of the IP 265 are designed for 24 V DC. The signal lines of the sensors are to be

shielded and connected via the 9-pin sub D connector of the IP 265 marked "Input".

Connecting 24 V digital outputs

The digital outputs of the IP 265 are designed for 24 V DC. The signal lines of the digital actuators

are to be shielded and connected via the 9-pin sub D socket marked "Output".

Connecting differential inputs

The signal lines of the sensors with 5 V differential signals are connected via the 15-pin sub D soc-

ket of the IP 265 marked "Interface". Signal lines of up to 32 m are possible. The signal lines must

be shielded Pre-fabricated standard cables can be ordered (see Appendix C). If pre-fabricated cable

is not used and if a sensor with 5 V differential signals is to be connected to the IP 265, the 5 V sen-

sor line must also be shielded.

Example: A pulse sensor is to be connected to the IP 265.

Figure 2-2 Connection Example for 24 V Digital Input

a

5 V

a

IP 265 ground (central

ground)

a

1

2

3

4

5

a

6

7

8

9

I

N

P

U

T

a

I

N

T

E

R

F

A

C

E

a

1

2

3

4

5

a

6

7

8

9

10

a

11

12

13

14

15

Pulse sensor

a

5 V Va

a

Shield

a

0 V

Pulse sensor

a

24 V

a

Shield

a

24 V

a

0 V

a

External supply

a

External supply

a

Connection of counting pulse sensor for 5 V RS 422

differential signal

a

Connection of counter pulse sensor for 24 V DC

a

IP 265 ground (central

ground)

2-2 EWA 4NEB 812 6131-02

Standard Function Counter Installation Guidelines

Cable connection conditions

To ensure the correct functioning of the IP 265, there are important rules to be observed concerning

wiring and shielding. Since the IP 265 can only be used in conjunction with the S5-100U, S5-

90/95U or ET 200, it is assumed that you possess one of the relevant manuals. In the manual you

will find details of all cable connection conditions for programmable controllers (PLCs).

The following information refers only to the shielding of the connection cable.

Notes on cable shielding

Both ends of shielded cables should have a good electrical connection to the cabinet’s chassis

ground. You can effectively suppress interference of all coupled frequencies only if the cables are

shielded at both ends. The shield should reach the module and should also be connected to the

module!

Note

There can be a compensating current flowing across cables shielded at both ends if

there are ground potential fluctuations. You should therefore join the connected

components with an additional equipotential bonding cable.

With SIMATIC controllers, the interference current on cable shielding is discharged to ground both

via the shielding rail and the equipotential bonding cable. To prevent these discharged currents from

becoming a source of interference, ground them on a low-resistance path as follows:

• Tighten the hold-down screws on the cable connectors, modules, and equipotential bonding

cables.

• Protect the contact surfaces of equipotential bonding cables against corrosion.

EWA 4NEB 812 6131-02 2-3

Installation Guidelines Standard Function Counter

2.4 Further Notes on Configuring and Installing the Module

As the module is usually used as a component in larger systems or plants, the following notes are

intended to help you safely integrate the module into its environment.

Notes to be observed for the installation and startup of the module, depending on individual

applications:

Warning

• Adhere to any safety and accident-prevention regulationsapplicable to your

situation and system

• If your system has a permanent power connection (stationary equipment) that is

not equipped with an isolating switch

and/or fuses that disconnect all poles, install either a suitable isolating switch or

fuses in the building wiring system. Connect your system to a ground conductor.

• Before startup, if you have units that operate using the main power supply,

makes sure that the voltage range setting on the equipment matches the local

main power voltage.

• When using a 24 V supply, make sure you provide proper electric isolation

between the main supply and the 24 V supply. Use only power supplies

manufactured according to IEC 364-4-41 or HD 384.04.41 (VDE 0100, part 410).

• Fluctuations or deviations of the supply voltage from the rated value may not

exceed the tolerance limit specified in the technical data. If they do, functional

failures or dangerous conditions can occur in the electronic modules or

equipment.

• Take suitable measures to make sure that programs that are interrupted by a

voltage dip or power failure resume proper operation when the power is

restored. Make sure that dangerous operating conditions do not occur even

momentarily. If necessary, force an EMERGENCY OFF.

• EMERGENCY OFF devices must be in accordance with EN 60204/IEC 204

(VDE 0113) and be effective in all operating modes of the equipment. Make

certain you prevent any uncontrolled or undefined restart when the

EMERGENCY OFF devices are released. Install power supply and signal cables

so that inductive and capacitive interference cannot affect the automation

functions.

• Install your automation system and its operative components so as to prevent

unintentional operation.

• Automation equipment can assume an undefined state in the case of a wire

break in the signal lines. To prevent this, take the proper hardware and software

safety measures when linking the inputs and outputs of the automation

equipment.

2-4 EWA 4NEB 812 6131-02

Standard Function Counter Input and Output Signals

3 Input and Output Signals

You control the functionality of the counter via the digital inputs of the IP 265 and via data that is

transferred to the IP 265 from the CPU via the process image of the outputs (PIQ)

3.1 Counter Pulses at the CU1 and CU2 Input

This input is a direct link with your process. The counter pulses to be processed by the program are

applied here.

In the standard function, two inputs per counter channel are provided for the counter pulses:

• One counter input for 24 V signals up to a limit frequency of 10 kHz.

• One high-speed counter input for 5 V differential signals to RS422A with a limit frequency of

58 kHz.

Timing of the counter pulses at the CU1 and CU2 input (5 V differential input)

The following conditions must be observed for the sensor signals:

a

A

a

min. 8.6 µs

a

min. 8.6 µs

a

min. 8.6 µs

a

min. 8.6 µs

a

A-N

This results in a minimum pulse time of 17.2 µs. The maximum input frequency is then 58 kHz.

The mark/space ratio is variable. However, the minimum time limits must not be violated.

EWA 4NEB 812 6131-02 3-1

Input and Output Signals Standard Function Counter

3.2 Signals that have an Influence on Counting

Counting is influenced by additional signals over hardware inputs or paramters in the PIQ.

3.2.1 Resetting an Output (RSQ)

There is an RSQ signal for every counter channel. The assigned ouptut A can be reset with the

RSQ signal. The input responds to the rising edge of the RSQ signal. The counter status is not

influenced by setting RSQ.

3.2.2 Resetting a Counter Channel (RSC)

There is an RSC signal for each counter channel. The rising edge of the signal sets the counter

status of the assigned channel as follows:

• to zero in the case up counting (normal counter function)

• to the specified setpoint in the case of down counting (periodic counter function and cascading

function).

In addition, down counting resets any output which has been set.

3.2.3 GATE Signal (GATE)

You can interrupt an active count with the active GATE signal.

The signal GATE = "1" stops the count despite pending counter pulses. The assigned output is

switched off simultaneously if it was switched on.

The state remains until the GATE signal is set to "0" again.

With the value GATE = "0", the output is returned to the old state and the count is continued

simultaneously.

The GATE signal is subordinate to the RSQ and RSC signals, i.e. the RSQ and RSC signals remain

functional even if the count is stopped.

3.3 Counter Output

Each counter channel of the standard function counter is assigned an output and the corresponding

negated output of the IP 265. Signalling of a set output via a bit in the PIQ runs parallel to this.

Outputs are set when the count passes zero only in the down counting functions (PCF (periodic

counter function) and CAF (cascade function)).

Outputs can be reset by the rising edge of the following:

• RSQ signal

• RSC signal

3-2 EWA 4NEB 812 6131-02

Standard Function Counter Input and Output Signals

3.4 Location of the Signals in the Process I/O Images

The location of the inputs and outputs on the module is described in Section 2. The locations in the

process I/O image are as follows:

RSC2 RSC1 RSQ2 RSQ1 GATE2GATE1

a

Q2 Q1

a

Location of the control signals in the signal byte:

PIQ

a

Location of the outputs in the output byte:

PII

a

Bit 7 Bit 0

Byte No. 6

a

Bit 7 Bit 0

Only the control signals and the output signal of channel 1 are decisive for the cascade function.

Output Q2 is always "0" in the cascade function.

3.5 ORing and Evaluating Signals

There are two signal inputs for different signals of the standard function counter:

• Hardware inputs

• PIQ data

These "inputs" are ORed with each other internally. They are always active simultaneously and can

be driven independently of each other.

This means, for example:

• The CU counter pulses can be routed either via a 24 V digital input or a 5 V digital output.

• The signal for resetting the counter channel (RSC) can be given either via a 24 V digital input or

via a bit in the PIQ of the CPU.

The outputs are active at the hardware output and in a bit in the PII simultaneously. The negated

output signal has no equivalent in the PII.

Table 3-1 ORing the Interfaces of the Standard Counter Function

Signals 24 V

DI 5 V DI PIQ 24 V

DQ PII Signal Evaluation

Edge-Triggered Value-Triggered

CD • • Rising Edge

RSQ • • Rising Edge

RSC • • Rising Edge

GATE • • ”1”

Q••--- ---

Q\ • --- ---

EWA 4NEB 812 6131-02 3-3

Standard Function Counter The Counter Functions

4 The Counter Functions

The program offers you three different function modes for your applications. You can change these

modes according to your needs via the STEP 5 program. The functions are called:

• Normal counter function NCF

• Periodic counter function PCF

• Cascade function CAF

Two independent 16-bit counters can be used in the NCF and PCF.

A 32-bit counter is available for the CAF.

Normal counter function NCF

The normal counter function is a simple 16-bit up counter. Each counter pulse at the CU input

increments the counter status by 1. When the maximum count has been reached, counting

continues from zero.

No outputs are set in this function; the outputs are generally reset.

Periodic counter function PCF

The periodic counter function is a 16-bit down counter. At the starting point of the periodic counter

function, the counter is set to a specified setpoint. Each counter pulse at the CU input decrements

the count by 1 starting from the setpoint. If the count reaches 0, the assigned output is set and the

count is reset to the setpoint.

A set output can be reset via the RSQ or RSC signals.

Cascade function CAF

The cascade function is a down counter like the periodic counter function but with a data width of 32

bits. It operates in the same way as the periodic counter function.

EWA 4NEB 812 6131-02 4-1

The Counter Functions Standard Function Counter

4.1 Selecting the Counter Function Mode

There are three bits available in the process image of the outputs (PIQ) for selecting the mode. You

use these bits to set the relevant mode. Both channels can be switched to the "normal counter

function" mode or the "periodic counter function" mode independently of one another.

Note

The function modes can only be set via the STEP 5 program and output via the PIQ

to the IP 265.

Location of the bits in the function mode byte:

CASC CF2 CF1

a

Bit 7 Bit 0

a

0 Periodic counter function counter 1

1 Normal counter function counter 1

a

0 Periodic counter function counter 2

1 Normal counter function counter 2

a

0 Function follows CF1 and CF2

1 Cascade function (independent of CF1 and CF2)

Byte No. 7 in the PIQ

Note

Setting and transferring the bits to the IP 265 does not yet start the new function.

Transfer of the bits by the IP 265 and starting of the new function mode are described in the next

section.

4-2 EWA 4NEB 812 6131-02

Standard Function Counter The Counter Functions

4.2 Transferring the Set Function Mode Using the IP 265

Switching from one function mode to another can be divided into the following steps:

1. Specification of the function mode using the CASC, CF1 and CF2 control bits.

2. Transfer and start of the new function with the RSC1 and RSC2 control bit.

4.2.1 Switching from Two-Channel Mode to Cascade Mode

If you want to switch the standard counter program from two-channel mode (PCF, NCF) to single-

channel mode (CAF), follow these steps:

• Set the CASC bit to "1".

• Set both reset signals RSC1 and RSC2 to "1".

Note

In order to switch on the cascade function, both reset signals RSC1 and RSC2 must

be set simultaneously. This is only possible if both signals are transferred to the IP

265 over the PIQ in the same data cycle.

The IP 265 detects both rising edges and switches the standard function to the cascade function.

Note

When the cascade function is switched on, only the data and control bits of channel

1 are active. Changes to channel 2 have no effect.

4.2.2 Switching from the Cascade Function to Two-Channel Mode

You switch the standard counter program from single-channel mode (cascade function) to two-

channel mode (PCF, NCF) as follows:

• Set the CASC bit to "0"

• Set the RSC bit to "1".

This resets both channels. The new function in which you then work follows the assignment of bits

CF1 and CF2

CF1 = 0 CF1 = 1

CF2 = 0 Channel 1 in PCF

Channel 2 in PCF Channel 1 in NCF

Channel 2 in PCF

CF2 = 1 Channel 1 in PCF

Channel 2 in NCF Channel 1 in NCF

Channel 2 in NCF

EWA 4NEB 812 6131-02 4-3

The Counter Functions Standard Function Counter

4.3 Counter Statuses and Signal Flow in the Three Function Modes

The interplay of the individual signals and the sequence of a count process are essential to an

understanding of the functions. For this reason the signal sequence is described briefly in the

following two subsections.

4.3.1 The Normal Counter Function

The normal counter function is a 16-bit up counter which works without setpoints and has no direct

access to the IP output.

The following example should make the signal sequence clear.

Before the start of the function, the counter was set to the PCF function on both channels.

The output of channel 1 was set.

Figure 4-1. Pulse Diagram for Channel 1

0

RSQ1

GATE1

65535

8 7 6 0 1 2 3

a

021 20

CS1

CU1

Q1

CF1

CASC

RSC1

Time of function selection

Reset pulse for counter (asynchronouus to

counter pulse) Counter

overflow Reset counter 1

1

0

1

0

1

0

. . . .

1

0

a

0 1 2 1 2 3

a

CS1 = Counter status 1

"Normal counter function" is selected for channel 1 with CF1 = 1 .

The rising edge of the RSC1 signal sets the counter to the start value "0" for NCF

Output A is switched off when you switch to the normal counter function. This output is not set in

the normal counter function.

Reset signals via input RSQ remain without effect for this reason.

The GATE signal is transparent throughout, i.e. the reset signals for the counter can still be

switched even when the GATE signals are active.

However, pending counter pulses do not change the current counter status.

4-4 EWA 4NEB 812 6131-02

Siemens SIMATIC S5 User manual

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