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6043-2202
Flow control
The RS-232 flow control can be done in two different ways, software XON/XOFF or
hardware RTS/CTS. This is individually selectable for each connected unit.
The system itself has flow control internally on the RS422/485 bus. The internal flow
control is used to transfer the hardware control signals across the network and indicates
that the buffer is full.
A MA-43 system can have different baudrates for different connected equipment.
Because of this there can be flow control signalling introduced by the MA-43 units. This
means for example, that if an XON/XOFF protocol is used the XOFF signal can be sent
by either the addressed user equipment or one of the two MA-43s which are involved in
the talking, if a buffer is filled up.
RTS/CTS
The CTS signal is used to control the data stream from a user to a MA-43. CTS is high
when the MA-43 is ready to receive characters.
The RTS signal is used to control the data stream from a MA-43 to the user. When the
user equipment is ready to receive characters RTS has to be high.
LED Indicators
MA-43 has 7 LED indicators. The LEDs has the following function.
POWER: Fixed light indicates normal function. If it is flashing the unit is faulty
(watchdog).
RD:
Indicates RS-232 receiving data. Light off when no data received.
DCD:
Lights when this slave is addressed, flashing when master is in test mode.
RTS:
Lights when connected unit has RTS in active state.
CTS:
Lights when MA-43 is ready to receive data.
TD:
Indicates RS-232 transmitting data. Light off when no data transmitted.
RXBUS:
Lights when data is received from the bus. This LED is only visible
when the box is open.
2-Wire system
When a slave has anything to send this will be sent as soon as the slave is addressed.
The MA-43 can not follow application protocols, so it is possible to get data collision on
the 2-wire bus if the user protocol is not disciplined. i.e the equipment cannot answer
polls or commands before the whole message is received from the talking partner.
AUDIN - 8, avenue de la malle - 51370 Saint Brice Courcelles
Tel : 03.26.04.20.21 - Fax : 03.26.04.28.20 - Web : http: www.audin.fr - Email : [email protected]
