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HEIDENHAIN Technical Manual TNC 426, TNC 430
Synchronization
A synchronization process ensures that the receiver correctly detects the first
character of a transmission.
With an asynchronous character frame, the transmission of a data word can
begin at any time, starting from an idle state.
A start bit is transmitted before each data word. If the first bit of the data word
had the same value as the idle state, the receiver would not notice any
difference from the idle state.
After the start bit has been sent, the data word is transmitted, bit by bit,
starting with the LSB (Least Significant Bit). The MSB (Most Significant Bit) of
the data word is followed by the so-called parity bit in order to detect
transmission errors.
The character frame is concluded by one or two stop bits. The stop bits enable
the receiver to recognize the transmitter again before the start of the next
character.
Synchronization is repeated before each character and applies for one
character frame.
Transmission
reliability: Parity bit
With an asynchronous character frame, transmission errors can be detected
by using the parity bit.
The parity bit can take three different forms.
n
No parity check: Error detection is dispensed with.
n
Even parity:
The transmitter counts bits with a value of one. If the number is odd, the
parity bit is set to one, otherwise it is cleared to zero. The sum of set data
bits and the parity bit is therefore always even. Upon receiving a word, the
receiver counts all of the set bits, including the parity bit. If the count is odd,
there is a transmission error and the data word must be repeated, or an error
message will be displayed.
n
Odd parity:
The parity bit is so chosen by the transmitter that the total number of all the
set bits is odd. An error will thus be detected if the receiver observes an
even number of set bits in its evaluation.
Example
The letter “z” corresponds to the bit sequence: 1 1 1 1 0 1 0
Parity bit
n
with even parity = 1
n
with odd parity = 0
Idle
sate
Idle
state
Character frame
Data bits
Start
bit
1 to 2
Stop bits
Parity
Bit
Bit 1
LSB
Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7
MSB
Summary of Contents for TNC 426 CB
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Page 51: ...December 2001 Software 2 41 ...
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Page 61: ...December 2001 Software Releases 2 51 ...
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Page 125: ...December 2001 Encoders 3 43 ...
Page 136: ...3 54 HEIDENHAIN Technical Manual TNC 426 TNC 430 ...
Page 141: ...December 2001 Touch Probe Systems 3 59 ...
Page 145: ...December 2001 Data Interface 3 63 ...
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Page 168: ...3 86 HEIDENHAIN Technical Manual TNC 426 TNC 430 ...
Page 183: ...December 2001 BTS 1x0 Monitor Keyboard Switch 3 101 ...
Page 187: ...December 2001 Dimensions 3 105 3 23 Dimensions Note All dimensions in mm ...
Page 191: ...December 2001 Dimensions 3 109 3 23 4 LE 430 M Max 9 Axes Weight approx 9 kg ...
Page 196: ...3 114 HEIDENHAIN Technical Manual TNC 426 TNC 430 3 23 9 BTS 110 ...
Page 197: ...December 2001 Dimensions 3 115 3 23 10 BTS 120 ...
Page 201: ...December 2001 Dimensions 3 119 3 23 14 Handwheels HR 130 Weight approx 0 7 kg ...
Page 202: ...3 120 HEIDENHAIN Technical Manual TNC 426 TNC 430 HR 150 Weight approx 0 7 kg ...
Page 203: ...December 2001 Dimensions 3 121 HR 410 ...
Page 205: ...December 2001 Dimensions 3 123 HRA 110 Weight approx 1 5 kg ...
Page 206: ...3 124 HEIDENHAIN Technical Manual TNC 426 TNC 430 Control knob for HR 130 and HR 150 ...
Page 207: ...December 2001 Dimensions 3 125 3 23 15 Touch probe systems TT 130 ...
Page 209: ...December 2001 Dimensions 3 127 TS 220 Adapter cable for TS 120 TS 220 ...
Page 210: ...3 128 HEIDENHAIN Technical Manual TNC 426 TNC 430 EA 6x2 Receiver Unit ...
Page 211: ...December 2001 Dimensions 3 129 TS 632 ...
Page 212: ...3 130 HEIDENHAIN Technical Manual TNC 426 TNC 430 APE 652 ...
Page 213: ...December 2001 Dimensions 3 131 ...
Page 214: ...3 132 HEIDENHAIN Technical Manual TNC 426 TNC 430 ...
Page 219: ...December 2001 3 137 3 24 5 Grounding plan TNC 426 M TNC 430 M with POWERDRIVE Inverter System ...
Page 231: ...December 2001 3 149 3 26 2 Cable Overview TNC 426 PB TNC 430 PA Basic Configuration ...
Page 240: ...4 2 HEIDENHAIN Technical Manual TNC 426 TNC 430 ...
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Page 319: ...December 2001 Overview of Modules 5 9 ...
Page 329: ...December 2001 Overview of Markers and Words 5 19 ...
Page 330: ...5 20 HEIDENHAIN Technical Manual TNC 426 TNC 430 ...
Page 349: ...December 2001 Machine Axes 6 19 ...
Page 357: ...December 2001 Machine Axes 6 27 ...
Page 381: ...December 2001 Axis Error Compensation 6 51 ...
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Page 463: ...December 2001 The Control Loop 6 133 ...
Page 468: ...6 138 HEIDENHAIN Technical Manual TNC 426 TNC 430 MP2600 0 MP2600 optimum ...
Page 476: ...6 146 HEIDENHAIN Technical Manual TNC 426 TNC 430 ...
Page 509: ...December 2001 Monitoring Functions 6 179 ...
Page 551: ...December 2001 Spindle 6 221 ...
Page 629: ...December 2001 Display and Operation 6 299 ...
Page 675: ...December 2001 Keystroke Simulation 6 345 ...
Page 709: ...December 2001 Touch Probe 6 379 ...
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Page 831: ...December 2001 Commissioning 6 501 ...
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Page 1114: ...December 2001 DSP Error Messages as of NC Software 280 476 01 10 21 ...
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