Transcript Siemens - Ecoursebox

Siemens
S7-200 PLC training courses
PLC history
• Classical control
- More complicated
- Longer time for maintenance
- Time consuming troubleshooting
- Occupies larger area in switchboards
- Requires more wiring
- Standard reliability
History
• Large projects requirements
-More inputs and outputs points
-Large program memory
-Several programming instructions
-Communication with other equipments
-Deal with analogue signals
-Deal with large number of counters, timers
and markers
History
• Historical view
Course contents
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Introduction to PLC
Bit logic
compare
Timers
Counters
Memory instructions
Analog I/O
Move , shift
Practical examples
Introduction
• What is a PLC
Introduction
• Basic PLC operation
introduction
• S7 200 family
introduction
• S7-200 configuration
introduction
• S7-200 configuration
mode switch and analog adjustment
introduction
• S7-200 configuration
optional cartidge
Introduction
• S7-200 configuration
expansion modules
Introduction
• S7-200 configuration
status indicator
Introduction
• S7-200 configuration
I/O numbering
Introduction
• S7-200 configuration
inputs
Introduction
• S7-200 configuration
outputs
Introduction
• S7-200 configuration
programming software
Analogue I/O
= Typical analogue signals from 0-10 VDC or 4-20 mA
= They are used to represent changing values such as
speed, temperature, weight and level
Introduction
Analogue outputs may be used to produce
variable reference signals for devices
such as:
# Control valves
# Chart recorders
# Electric motor drives
# Pressure transducers
# Analogue meters
Introduction
Introduction
Introduction
PLC Programming
Programming languages
Ladder diagram
The ladder diagram is the most
popular programming language
The instructions are represented
by graphic symbols:
Contacts, Coils & Boxes
Statement list
Function block
Instructions
Standard instructions:
They are used in most programs.
Examples: timer, counter, math, logical, incr., decr. and move
Special instructions:
They are used to manipulate data
Shift, table, conversion, real time instruction.
High speed instructions:
They allow for events and interrupts to occur independently of
the PLC scan time.
Examples: High speed counters and interrupts
Bit Logic instruction
Input Instructions
Normally Open contact
Normally Closed contact
Normally Open Immediate contact
Normally Closed Immediate contact
Positive Transition contact
Negative Transition contact
Not contact
Input contacts example
Output instructions
Output Instruction
Output Immediate instruction
No Operation instruction
Set (N bits) instruction
Reset (N bits) instruction
Set Immediate (N bits) instruction
Reset Immediate (N bits) instruction
Output, Set & Reset example
Starting a motor
Hard-wired DOL starting
O.L. contact
Circuit Breaker
Contactor
Thermal
Overload
Star
t
Stop
Aux. contact
Contact coil
Induction
Motor
Induction Motor
Using PLC
Before start
Starting
After start
Stopping
Input & Output connections
Timer instructions
On-Delay Timer
Retentive On-Delay Timer
Off-Delay Timer
On-Delay & Retentive On-Delay timers
They count time when the enabling input (IN) is ON.
When the current value (Txxx) is > the preset time (PT), the timer bit is ON.
The On-Delay timer current value is cleared when (IN) is OFF, while the
current value of the Retentive On-Delay Timer is maintained.
You can use the Retentive On-Delay Timer to accumulate time for multiple
periods of the input ON.
Off-Delay timer
The Off-Delay Timer is used to delay turning an output OFF for a
fixed period of time after the input turns OFF.
When (IN) turns ON, the timer bit turns ON immediately, and the
current value is set to 0.
When (IN) turns OFF, the timer counts till PT and the timer bit
turns OFF and the current value stops counting.
If the input is OFF for a time shorter than PT, the timer bit
remains ON.
Timers numbers & resolutions
Note
You cannot share the same timer numbers for TOF and TON.
For example, you cannot have both a TON T32 and a TOF T32.
Timer examples
On-Delay
Retentive
On-Delay
Off-Delay
Hard-wired on-delay timer
Timer example
TONR example
Timer example
Counter instructions
Up counter
Up/down counter
Down counter
A bottling machine, for example, may use a counter to count
bottles into groups of six for packaging.
Up-counter
It counts up on the rising edges of the Count Up (CU)
input.
When the current value (Cxxx) > (PV), the counter bit
(Cxxx) turns on.
The counter is reset when the Reset (R) input turns on.
Up/Down counter
It counts up on rising edges of the Count Up (CU) input.
It counts down on the rising edges of the Count Down
(CD) input.
When the current value (Cxxx) > (PV), the counter bit
(Cxxx) turns on.
The counter is reset when the Reset (R) input turns on.
Down counter
It counts down from the PV on the rising edges of the (CD) input .
When the current value is equal to zero, the counter bit (Cxxx)
turns on.
The counter resets the counter bit (Cxxx) and loads the current
value with the (PV) when the load input (LD) turns on.
Down-counter example
Up/down-counter example
Counter example
A counter might be used to keep track of the number of vehicles
in a parking lot. As vehicles enter the lot through an entrance
gate, the counter counts up. As vehicles exit the lot through an
exit gate, the counter counts down. When the lot is full a sign at
the entrance gate turns on indicating the lot is full.
The ladder logic
Memory types
• You can access data in many CPU memory areas
- process image input register
(I)
- process image output register
(Q)
- variable memory area
(V)
- Bit memory area
(M)
- sequence control relay memory area
(S)
- special memory bits
(SM)
- local memory area
(L)
- Timer memory area
(T)
- counter memory area
(C)
- Analog inputs
(AI)
Memory addressing
Accessing a Bit of Data in the CPU Memory (Byte.bit Addressing)
Memory addressing
You can access data in many CPU memory areas (V, I, Q, M, S, L,
and SM) as:
bytes, words, or double words by using the byte-address format.
Memory types
• Process-image input register (I)
Format:
Bit
Byte, Word, Double Word
I[byte address].[bit address] I0.1
I[size][starting byte address] IB4
• Process-image output register (Q)
Format:
Bit
Byte, Word, Double Word
Q[byte address].[bit address] Q1.1
Q[size][starting byte address] QB5
• Variable memory area (V)
You can use V memory to:
store intermediate results of the control logic operations. •
store other data pertaining to your process or task. •
Format:
Bit
Byte, Word, Double Word
V[byte address].[bit address] V10.2
V[size][starting byte address] VW100
Memory types
• Sequence control relay area (S)
They are used to organize machine operations or steps into equivalent
program segments. SCRs allow logical segmentation of the control
Format:
Bit
S[byte address].[bit address] S3.1
Byte, Word, Double Word S[size][starting byte address] SB4
• Special memory bits (SM)
The SM bits provide a means for communicating information between the
CPU and your program. You can use these bits to select and control some
of the special functions of the S7-200 CPU, such as:
• A bit that turns on for the first scan cycle
• Bits that toggle at fixed rates
• Bits that show the status of math or operational instructions
Format:
Bit
SM[byte address].[bit address] SM0.1
Byte, Word, Double Word SM[size][starting byte address] SMB86
Memory types
• Local memory area (L)
The S7-200 PLCs provide 64 bytes of local (L) memory of which 60 can be
used as scratchpad memory or for passing formal parameters to subroutines.
Format:
Bit
L [byte address].[bit address] L0.0
Byte, Word, Double Word
L [size] [starting byte address] LB33
Memory types
• Analog inputs (AI)
The S7-200 converts a real-world, analog value (such as temperature
or voltage) into a word-length (16-bit) digital value. You access these
values by the area identifier (AI), size of the data (W), and the starting
byte address. Since analog inputs are words and always start on
even-number bytes (such as 0, 2, or 4), you access them with evennumber byte addresses (such as AIW0, AIW2, or AIW4),as shown in
Figure Analog input values are read-only values.
Format: AIW [starting byte address] AIW4
Memory types
•Analog outputs (AQ)
The S7-200 converts a word-length (16-bit) digital value into a current
or voltage, proportional to the digital value (such as for a current or
voltage). You write these values by the area identifier (AQ), size of the
data (W), and the starting by address. Since analog outputs are words
and always start on even-number bytes (such as 0, 2, or 4), you write
them with even-number byte addresses (AQW0, AQW2, AQW4),
Format: AQW [starting byte address] AQW4
Move instructions
The Move Byte instruction moves the input byte
(IN) to the output byte (OUT). The input byte is not
altered by the move.
The Move Word instruction moves the input word
(IN) to the output word (OUT). The input word is
not altered by the move.
The Move Double Word instruction moves the input
double word (IN) to the output double word (OUT).
The input double word is not altered by the move.
The Move Real instruction moves a 32-bit, real input
double word (IN) to the output double word (OUT).
The input double word is not altered by the move.
The block move instructions
The Block Move Byte instruction moves the number of
bytes (N) from the input address IN to the output address
OUT. N has a range of 1 to 255.
Example
Move byte immediate instructions
The Move Byte Immediate Read instruction reads
physical input IN and writes the result in OUT.
The Move Byte Immediate Write instruction reads from
location IN and writes to physical output OUT.
Analogue I/O
= Typical analogue signals from 0-10 VDC or 4-20 mA
= They are used to represent changing values such as
speed, temperature, weight and level
=The expansion module converts the standard voltage and
current values to 12-bit digital representation. These digital
values are transferred to the PLC for use in its program
Analogue outputs may be used to produce
variable reference signals for devices
such as:
# Control valves
# Chart recorders
# Electric motor drives
# Pressure transducers
# Analogue meters
Analog o/p example
Analog i/p example
Analog i/p example