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HEIDENHAIN PT 855 for Turning User Manual

Page 74

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II - 4

Data Interface

76

Technical Information

POSITIP 855

Start bit

7 data bits

Parity bit

2 stop bits

Wiring the connecting cable

The wiring of the connecting cable depends on the device being
connected (see technical documentation for external device).

Full wiring

Simplified wiring

1

1

GND

2

3

4

5

6

20

7

TXD

RXD

RTS

CTS

DSR

GND

SIGNAL

DTR

CHASSIS

2

3

4

5

6

20

7

PT 855

GND

TXD

RXD

RTS

CTS

DSR

GND

SIGNAL

DTR

CHASSIS

1

GND

2

3

4

5

6

20

7

TXD

RXD

RTS

CTS

DSR

GND

SIGNAL

DTR

CHASSIS

1

GND

2

3

4

5

6

20

7

TXD

RXD

RTS

CTS

DSR

GND

SIGNAL

DTR

CHASSIS

PT 855

Setting the baud rate: P 50

The baud rate set on the POSITIP must be the same as that of the
external device. The external device must be capable of processing
the selected baud rate. The baud rate for the data interface on the
POSITIP is set with an operating parameter. The machine manufac-
turer can also make this parameter available as a user parameter
(see I - 6).

Settings for the baud rate
P 50 = 110, 150, 300, 600, 1200, 2400,

4800, 9600, 19 200, 38 400 [baud]

The baud rate for data transfer between POSITIP and
the FE 401 floppy disk unit is always 9600.

Data format

Data is transferred in the following sequence:
1. Start bit
2. Seven data bits
3. Parity bit (even parity)
4. Two stop bits

Interrupting data transfer

There are two ways to interrupt data transfer from the external de-
vice and restart it:

➤ Start/Stop over input RXD

DC3 = XOFF = CTRL S: interrupt data transfer
DC1 = XON = CTRL Q: resume data transfer

➤ Start/Stop over control line CTS

When the stop signal CTS or DC3 has been received,
POSITIP sends up to two further characters.

S D D D D D D D P S S

Fig. 41: Data transfer format

Fig. 39: Diagram for full wiring

Fig. 40: Diagram for simplified wiring