ABB Sensyflow FMT700-P, Operating Instruction

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Communication
42/14-42-EN Sensyflow FMT700-P 25
Asynchronous serial data transmission
The process whereby data is transmitted in small units of equal length without any additional
clock information is known as asynchronous data communication without clock signals.
The transmitter and receiver must be clear about the transmission conditions involved, e.g.:
• Transmission speed (baud rate)
• Word
length
• Number of start and stop bits (format)
• Bit
assignment
• Signal voltage
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6.1.1.1 Electrical properties
The voltage level of the transmit and receive data conforms to the EIA ( E lectronic I ndustries
A lliance) RS 232 C standard and is electrically isolated from the power supply for the
supply / evaluation unit.
G00943
0 V
+ 8 V
- 3 V
- 8 V
+ 3 V
Fig. 20: Voltage level of transmit and receive data
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6.1.1.2 Data format
Data transmission is bidirectional and uses ASCII code. The data format used is asynchronous
and involves a START BIT and two STOP BITS in each case.
START BIT 0 1 2 3 4 5 6 7 STOP BIT STOP BIT
The supply / evaluation unit is ready to receive data as soon as it is switched on. The baud rate
set at the factory is 9,600 bit/s.
The software description provided below relates to versions 7.10 and 7.11 (without "Totalizer").
Control characters used
Short form Description Hex code Decimal code
EOT E nd o f T ransmission 04 04
LF L ine F eed 0A 10
CR C arriage R eturn 0D 13
CLS Cl ear S creen 1A 26
IV I nverse V ideo 1B, 47, 34 27, 71, 52
DV D efault V ideo 1B, 47, 30 27, 71, 48
Important (Notice)
Although all the control characters listed are transmitted, they are not displayed on a potential
monitor.
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