1. Digital Concepts for PLCs
MAIN 222
Industrial Controllers
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2. Introduction Why Binary?
At the end of this lesson you will be able to define convert decimal to binary and define digital definitions as applied to PLCs.
What is difference between Bytes, Words and Nibbles?
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3. PLC Numbering Systems Decimal (base 10) Binary (base 2)
Counting
Binary (base 2)
2 levels 0 or 1 0-1
Octal (base 8) 0-7
Older computing/ processors
Hexadecimal (base 16) 0-9 A-F
Internet Addressing
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4. PLC Numbering Systems Bit Byte Word Nibble A single value 0 or 1
Counting 1-9
Byte
8 bits in a string
Word
2 bytes in a single string
Nibble
4 bits
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5. PLC Numbering Systems Integer is a whole number Floating Point Numbers
5 , -7 ,1024
Used in PLCs as a count method
Floating Point Numbers
Powers something that is raised 2^0 = 1
Weight of value
2^2 = 4 or 10s 100s s
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6. Bit Position Weighting
SEE BINARY BASICS SHEET
Work from MSB to LSB
Binary thumb-wheel
Converting Binary to Decimal
Convert Decimal to Binary
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7. IMPORTANT TEST QUESTION
If a Word is 2 bytes or a total of 16 values
Then what is largest number we can decimally go to?
32768
If we count higher what happens?
Reset or retrigger, bad, bad, bad
IN GE THIS IS CALLED A DOUBLE INTEGER
IN GE FANUC
Timers and Counters use 3 words of address
Convert Decimal to Binary
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8. Logic Gates AND GATE OR GATE INVERTER
All conditions must be satisfied
OR GATE
Only one condition must be satisfied
INVERTER
The input is opposite of output
Logical operation sequence must be correct
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9. Logic Symbols
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10. Summary Binary vs Digital Weights of numbers Logic Gates
Registers use inputted date
Weights of numbers
Logic Gates
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11. Where to Get More Information
Series X Student Guide
Binary handout sheet
Floyd – Digital Electronics
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