ADA-4040A converter with set up addressing is listening constantly to frame on RS485 bus via RS1 port. If received frame contains
byte of address equal to address of converter, then another bytes of frame are received, right up to silence on RS-485 bus equal to
'space between frames in signs'. If the frame is received correctly, the address byte is deleted and transmitted over as typical to the
RS2 port. In case of errors in received frame, it isn't transmitted to RS2. In this case should be send the previous frame one more.
The frame received from device connected to RS2 port is being tested of transmission errors and in case of their missing converter
adds address to beginning of frame and send it to RS-485 bus through RS1.
Frame containing errors isn't being transmitted to RS1 port.
In case of transmitting of frames containing more than 950 bytes converter receive only 950 bytes and next are ignored.
ADA-4040A has equipped with separate buffers for RS1 and RS2, therefore converter can operate in full duplex mode on RS-422 and
RS-485 4-wire bus.
Additionally, can be set data flow control for RS1 (RS485/RS422) interface and RS2 (RS485/RS422) interface according to pt.
CONFIGURATION BY THE USE OF ADACONFIG.
Figures below present possibility of using the addressable ADA-4040A baud rate converter.
Fig 9. Connection of no addressable RS422 devices to RS485 bus
Fig 10. Connection of RS485 bus segments with different baud rate and format data frame devices, additionally galvanic
separation of bus segments
12
ADA-4040A
Baud rate
9600 bps
RS-232
Bus
Device
RS-422
Addressable
Device
RS485
ADA-1040
ADA-4040A
Address 2
Baud rate
2400 bps
Device
RS-422
Device
RS-422
Baud rate
1200 bps
ADA-4040A
Address 1
Parameters on RS-485 bus :
- baud rate 19200 bps,
- 8 data bits,
- no parity control,
- 2 stop bits.
ADA-4040A
Address 3
RS-485 bus
2-wire or 4-wire
ADA-4040A
like repeater and baud rate
converter between RS-485 bus
segment
RS-485
addressable
device
Segment A
Master
device
Segment B
RS-485
addressable
device
RS-485
addressable
device
RS-485
addressable
device
Parameters on segment A of RS-
485 bus :
- baud rate 19200 bps,
- 8 data bits,
- no parity control,
- 2 stop bits.
Parameters on segment B of
RS-485 bus :
- baud rate 4800 bps,
- 8 data bits,
- no parity control,
- 2 stop bits.
Summary of Contents for ADA-4040A
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