Device description
Le
u
ze electronic
MA 255
i
15
TNT
35/7-2
4
V
4
Device description
4.1
General Information to the connector units
The modular interfacing unit of the MA 2xx
i
family is a versatile gateway for integrating Leuze
RS 232 devices (e.g., BCL 22 bar code readers, RFID devices, RFM 32, AMS 200) in the
respective fieldbus. The MA 2xx
i
gateways are intended for use in industrial environments
with a high protection class. Various device versions are available for the conventional
fieldbuses. With a stored parameter structure for the connectable RS 232 devices,
commissioning could hardly be simpler.
4.2
Characteristics of the connector units
A special characteristic of the MA 255
i
device family are three function modes:
1.
Transparent mode
In this function mode, the MA 255
i
functions as a pure gateway with automatic
communication from and to the PLC. Absolutely no special programming by the user
is necessary for this purpose. The data is not buffered or stored temporarily, however.
Instead, it is "passed on".
The progr
a
mmer m
us
t m
a
ke cert
a
in to retrieve the d
a
t
a
from the inp
u
t memory of the
PLC
a
t the right time,
as
it i
s
otherwi
s
e overwritten
b
y new d
a
t
a
.
2.
Collective mode
In this operating mode, data and telegram parts are temporarily stored in the memory
(buffer) of the MA and sent to the RS 232 interface or to the PLC in a telegram by means
of bit activation. In this mode, however, all communication control must be
programmed on the PLC.
Thi
s
f
u
nction mode i
s
helpf
u
l, for ex
a
mple, for very long telegr
a
m
s
or when one or
more code
s
with long code length
s
a
re re
a
d.
3.
Command mode
With thi
s
s
peci
a
l oper
a
ting mode, it i
s
po
ss
i
b
le to
us
e the fir
s
t
b
yte
s
of the d
a
t
a
r
a
nge
to transmit predefined commands to the connected device by means of bit activation.
For this purpose, device-dependent commands (so-called online commands) are
predefined via the device selection switch, see chapter 16 "Specifications for Leuze
end devices".
