Siemens Simatic S5-101U Installation manual

SIEMENS
Pr~gramma~bleController
Programming Instructions Order No.: GWA 4NEB 810 2120-02 a
Fig.
1 S5-101U programmable controller
CONTENTS Page Page
THE PROGRAMMING LANGUAGE 4.2.1
STEP 5 programming language
1.1 4.2.2
Program structure
1.1 4.2.3
PRINCIPLE
OF OPERATION 4.2.4
OF THE PC
Program processing 2.1
"RUN and "STOP" modes 2.2 5.
Memor i es 2.2 5.1
5.1.1
NOTES ON PROGRAM DEVELOPMENT 5.1.2
Power-up 3.1 5.1.3
Battery mon
i tor i ng 3.2 5.1.4
Renten
tive/non-rententive 5.1.5
flags 3.2 5.1.6
Interrupt processing 3.2
Intercompatibi
l i ty between 5.1.7
LAD, CSF and STL 3.4 5.1.8
Operation in the SINEC L1 3.7 5.2
local area network 5.2.1
5.2.2
PROGRAM START-UP 5.2.3
Loading and dumping a 5.2.4
program
4.1 5.2.5
Program test 4.2 6.
Search function
Signal status display
Forcing of outputs and
flags
Forcing of timers and
counters
PROGRAMMING EXAMPLES
Basic operations
Binary logic operations
Setting/resetting operations
Load and transfer operations
Timer functions
Counter functions
Comparison (relational)
operations
Arithmetic operations
Other functions
Supplementary operations
Logic operations (word mode)
Conversion functions
Shift operations
Jump operations
Cond
i t i on codes
OPERATION SET

1. The programming language
1.1 STEP 5 programming language
The user programs are written in the
STEP 5 programning language. The
statements of this
l anguage permit
not only the programning of simple
binary functions but also the pro-
gramming of complex digital functions.
Depending on the programmer used, all
three methods of representation
statement list (STL)
1adder d
i agram (LAD)
control system flowchart (CSF)
are possible so that the method of
programming can be adapted to the
particular application. Only STL pro-
gramming is possible with the hand-
held 605U programmer. The machine
code generated by the 6701675 pro-
grammers is identical for all
three methods of representation
..
1.2 Program structure
The user program consists of up to 1024
statements and can be written as a pro-
gram block (PB) or function block (FB).
WFy PBl at FBI can k exwwted on %c
S5+1O1U programable contrallsr,
Program block
A program block can be programmed and
documented in
a11 three methods of re-
presentation (STL, LAD and CSF).
A pro-
gram block can be translated from one
method of representation into the two
other methods with the 6701675 program-
mers provided certain programming rules
are observed (see Section
3.4).
For users familfar with contactors and
re1ays, the LAD method is recommended
since the ladder diagram has very close
similarities with schematic circuit
diagrams.
Program blocks are used especially
when a CRT-based programmer is avail-
able and programming or documen-
tation is to be made in graphic form.
Fig.
2: Methods of representation with
the STEP 5 programming language
to
3lN 19 239 idrcftl
Function block
Function blocks can only be written
and documented in STL form.
Jump operations make
it possible to
enhance the structuring of the user
program and thus also its capabilities.
Short, constant response times to inter-
rupts can be implemented with load and
transfer operations in conjunction with
jump operations (see Section
3.4).
Note: Supplementary operations must
not be used in
PB1.
+o
2lh 19 239 Idrcctl
to
KC 117-15
DIN L3 705
DIN 40 719
DIN 19 23i , lrrlfti

2. Principle of operation
2.1 Program processing
The control functions of the lOlU are
defined by a user program.
In order to be able to scan the user
program cyclically statement by state-
ment, the CPU has to perform the follow-
ing functions:
1. In the case of a cold restart (power
switch from
"Off" to "On" or mode
selector from "Stop" to "Run"), the
process output image* is erased,
i.e. all outputs are set to zero.
2. The process input image* is updated,
i.e. all signal statuses of the in-
puts are scanned and written into
the process input image.
The user program (PB1 or FBI) is
scanned and processed statement by
statement. When scanning the signal
statuses of the inputs, the
CPU ac-
cesses the process input image and
not the actual inputs. When latching
and unlatching the outputs (coils),
only the process output image is
overwritten to begin with.
4. Once the user program has been pro-
cessed, the process output image
is transferred to the actual out-
puts.
5. Points 2, 3 and 4 are handled cycli-
cal
ly.
Cold restart
Cr>
Erase process
output image
I Cycle checkpoint
Read process
input image
12nd statement I
Last statement
H
Transfer process I
output image to
the outputs
Fig. 3:
Principle of operation of the
S5-101U
A scanning operation from cycle check-
point to cycle checkpoint takes approx.
70 ms for 1024 statements (binary).
If a scanning cycle is not completed
within 300 ms due to program errors
* Process 1/0 image:
or faults, an internal monitor responds, Internal memory area in which the
the PC enters the "Stop" status and signal status ("0" or "1") of the
all outputs (coils) are switched off. inputs/outputs is stored.

The "Run" and "Stop" modes
"RUN" mode
p-
In the "RUN" mode, the program is scanned
cyclically from cycle checkpoint to
cycle checkpoint. The PC is brought
into the "RUN" mode by
- switching the mode selector to "RUN1'
- selecting the "PC RUN1' function of
the programner (mode selector in "RUN"
position)
- and on recovery of the power supply
if the mode selector is at "RUN" and
was in the "RUN" position prior to
the power failure.
Memories
The PC has an internal program memory,
the data of which can be supported for
three years by a backup battery.
There are also two different memory
submodules (see Fig. 4).
"STOP" mode
In the "STOP" mode, the program is not
scanned and the outputs (coils) are
disabled. While the PC is in the "STOP"
state, all timers and counters and the
process 1/0 image retain the values
or states they had in the last scanning
cycle prior to the PC entering the "STOP"
state.
If the PC is switched to "RUN",
the timers and counters (0
... 7) are
reset. The non-retentive flags and the
process 1/0 image are erased.
The
PC is brought into the "STOP" mode
by
- switching the mode selector to "STOP"
- selecting the "PC STOP" function on
the programmer
- faults or errors in program scanning,
e.g. time-out or operations that can
not be interpreted by the PC.
The cause for the PC entering the 'STOP"
state can be traced with the aid of
the "DISPLAY ESTACK" function of the
programner (see Section 4.2 of Operating
Instructions).
The memory submodules are used for pro-
gram dumping or for copying the program
should only one memory submodule be
used for a number of PCs.
On power-up or when the PC is switched
to
"RUN", the contents of the memory
submodule are always copied into the
internal memory and processed there.
Fig. 4: Differences between the EPROM and EEPROM submodules.
Memory submodu
l e
Program
dump
Program
erasure
Program mod
i -
fication via
programmer
EPROM
PG 615 (with adapter 984-2UAll)
PG 670 (with adapter 984-OUAll)
PG 675
Only with special UV lamp
(erasure time: 30 min)
On 1~
erasure of entire
program possible
EEPROM
PG 615
PG 670 (without 984
adapter)
PG 675
Direct in the PC with
the above programmers
and the PG 605U pro-
9
r amme r
Programmer function:
PG PC)
possible

3. Notes on program development
Power up
When the power supply is switched on
or on recovery of the power supply after
a power failure, the PC assumes the
following states without having to
take any additional measures in the
user program:
Fig.
5: Automatic mode setting
following power-up
Prevention of automatic restart in
general
Flag* F 63.7 can be used to prevent
automatic restart on power-up.
This flag is set by the operating
system of the PC on power-up
if
the "RUN" mode is set and was set
prior to power-down. In order to
enable manual restart, flag F 63.7
is reset in the "STOP" mode.
It can
also be reset by the user program (e.g.
in conjunction with an input signal).
Error
i dent i -
f ier* set
- YE S --------t
I NO
Operating mode
of PC prior to
power-up
STOP
RUN
POWER OFF
l
POWER ON
* Internal re1ay equivalent
Operating
mode follow-
i ng power-up
- STOP
STOP
S TOP
- RUN
Current position
of mode selec-
tor of the PC on
power-up
-
STOP
L RUN
Programning example
)+ F63.7; "1"
I
I
User-
!
I
I--- F63 7 & "9"
l I
* A fault has occurred in program scanning
and the reason for this is stored
in the interrupt stack.
Preventinq automatic restart on battery
fail ure
Flag F 63.6 can be used to prevent auto-
matic restart on battery failure (reten-
tive flags reset).
Flag F 63.6 is set by the operating
system of the PC on power-up
if the
backup battery fails or is not connec-
ted. The PC must be set to the "RUN"
mode in this case.
Flag F 63.6 is reset by the "ERASE
PROGRAM" function or by the user pro-
gram (e.g. in conjunction with an input
signal).
Programming example

3.2 Battery monitoring
Flag F 63.6 is used for monitoring the The PC must be in the "RUN" state.
battery. Flag F 63.6 is reset by the "ERASE PRO-
This flag is set by the operating system
GRAM" function of the programner or by
of the PC on power recovery and during the user program. The user can therefore
the normal scanning cycle
if failure determine how the PC is to react to
of the battery backup v01tage is detected. backup battery failure.
The S5-101W has a total of 512 flags.
The flag area is subdivided as follows:
Retentive flags (F 0.0
... F 31.7)
- retain their last state prior to -
power-down on power-up (with backup
battery only)
- retain their last state when the
mode is changed from "STOP" to "RUN"
(with and without backup battery)
- are reset like the non-retentive
flags on power-up (without backup
battery)
- can also be reset by the user pro-
gram
( " ERASE PROGRAM" function ).
By using retentive flags, the last
status of the plant or machine prior
to the PC leaving the "RUN" mode can
be stored. On restart, the plant or
machine can resume operations at the
point at which
it was stopped.
Interrupt processing
When an interrupt signal (e.g. emer-
gency off) from the process is re-
ceived by the PC, the latter inter-
rupts cyclic scanning of the user program
and inititates the processing of a
specific interrupt routine.
Interrupt processing with the S5-101U
is defined exclusively by the user pro-
gram so that each input and output can
be used for interrupt processing.
Non-retentive flags (F 32.0.. .F 63.7)
- are reset when the PC mode changes
from "STOP" to "RUN" and on power-up.
Flags F 61.0
- F 62.7 are reserved
as coordinating
fl ags for operation
in the SINEC L1 local area network;
flags F 63.0
- F 63.7 are reserved
as system flags. Since they are af-
fected by the PC operating system,
they must not be used as flags in
the normal sense.
In order to achieve minimum response
times, the inputs and outputs are re-
ferenced direct, i.e. outside cyclic
program scanning. The load/transfer
operations "LPB" (inputs) and "TPB"
(outputs) are available for this pur-
pose.
A more or less constant response time
is achieved
if the scanning of the in-
puts programmed by the user as interrupt
inputs is uniformly distributed over
the entire user program. Fig. 6 shows
a user program with interrupt processing.

Task: When input I 0.0 becomes "l",
outputs Q @.g. .. Q 0.7 are to assume
the state of flags F 3.a
... F3.7. In
order to keep the response time as
short and constant as possible, ten
interrupt scans should be written in
the user program.
User
program
STEP
5 program (STL)
Interrupt
routine
Expl
anations
1st interrupt scan: by loading PB
0,
I 0.0 is scanned direct, i.e. by-
passing the process image, and mapped
on F
@.a.
If F 0.0 (and consequently
I 0.0)
is "l", a jump is made to the
interrupt routine.
F 10.0 defines the
return address.
2nd
i nterrupt scan
10th interrupt scan
Flag byte FB3 is transferred direct into
peripheral byte PB
0, i.e. direct to
the outputs. The process output image
is updated.
By scanning flags
F 10.0 ... F 11.0 (only
one flag is used), the user program is
continued at the return address last
defined.
Fig.
6: Example of a user program with interrupt scanning

3.5
Intercompatibility between LAD, CSF and STL
General
Each of the methods of representa-
tion in the STEP
5 programming
languages has specific properties
and limitations.
Consequently, a program block written
in STL cannot simply be displayed as
an LAD or CSF and the graphic methods
of representation, LAD and CSFy may
not always be fully compatible.
Inother words, one form cannot al-
ways be translated back into the
other form.
If the program has been entered as Fig.
7: Range and limitations of the
an LAD or CSF,
it can always be trans- methods of representation in the
lated back into STL form. STEP
5 programming language
Input Output
The aim of this section is to establish
a number of rules, which,
if adhered to,
will ensure complete compatibility be-
tween the three methods of representation.
These rules are classified as follows:
- Rules for compatibility between the
graphic methods of representation
(LAD and CSF)
.
If these rules are followed, input is
possible in one graphic form and display
in the others.
Fig.
8: Graphic input
I nput Output
- Rules for compatibility between the
statement list and the graphic methods
of representation.
If these rules are observed, it is
possible to enter a program in any
if
the three methods of representation,
graphic or not, and to have
it dis-
played in the other two forms.
Fig.
9:
Input inthe form of a statement list

Input as LAD and dis~lavas CSF (STL)
Rule: Do not exceed the display
boundaries for LAD.
Excessive nesting may cause the LAD
display boundary to be exceeded
(8 levels)
max .4
Example of maximum LAD nesting for display as CSF
Input as CSF and display as LAD (STL)
Rule 1: Do not exceed the display
boundaries for LAD.
Too many inputs on a CSF box cause
the
l adder diagram display boundary
to be exceeded.
CSF
Fig. 11: Example of a maximum AND box inCSF form for display as an LAD

Rule 2: The output of a complex ele-
ment (memory, comparator, timer and
counter) must not be ored.
Fig. 12: Only AND boxes are allowed in.CSFs after a complex element.
In~utas STL and display as LAD or CSF
Rule
1:
A complex element must not have In addition, every unused input or out-
a preceed i ng operation. put must be assigned an NOP 0 operation.
Rule 2: The inputs and outputs of com- In the case of timers and counters, the
plex elements must be programmed in set input and the input for loading the
the order inwhich they are assigned time (TW) or count (ZW) must be dis-
parameters on the screen in graphic abled together.
mode.
Times and counts are exceptions since
the relevant value must first be stored
inthe accumulator with a load operation.
STL LAD CSF
Fig. 13: Example for assigning NOP operations to unused inputs and outputs