KROHNE BM 70 A_P EN - Manual (Page 48)

Installation and operating instructions BM 70 A/P Page: 48 11/00
8.6.9 Communication interfaces
Fct. 3.3.5 BAUDRATE
•
This function defines the transmission rate for RS 485
Communication.
•
1200 Bd.
•
2400 Bd.
•
4800 Bd.
•
9600 Bd.
•
19200 Bd.
•
38400 Bd.
Default value = 19200 bauds
•
For devices with PROFIBUS-PA (Ex-i) output the value
has been set to 31250 bauds. and cannot be changed.
•
The value set here is not relevant for digital
Communication via the current output (e.g. HART
®
).
For this, 1200 bauds are on principle processed,
independent of the setting in Fct. 3.3.5!
Fct. 3.3.6 ADDRESS
•
This function is used for entering valid addresses from
0 to 255 (PROFIBUS: 0 to 126).
•
If several devices are operated on one digital bus or
via HART ® -Multidrop, each device must be set to an
individual address under which it can then be
addressed in the bus.
•
The default value is the address "0".
Fct. 3.3.7 PROTOCOL
The following Communications protocols are available:
HART
®
:
The HART
® protocol is a Communications protocol of the
"HART ® Communication Foundation". In addition to the
"universal commands" and "common practice commands"
there are "device-specific commands" for access to all
parameters and functions of the BM 70 A/P. In addition
there is the "device description" (DD) for BM 70 A/P, which
can be used for universal HART
®
control units, such as the
HART
®
Communicator or SIPROM.
The standard hardware platform for HART
®
is the current
output 4-20 mA with superimposed FSK signals. For
HART
®
-Multidrop (max. 15 devices on one bus), the
version with Ex-i current output, set to a constant 4 mA
(Fct. 3.3.1 = OFF) should be selected.
KROHNE/PC (KROHNE protocol):
The standard Communications protocol between the
BM 70 A/P and the evaluation system is the standardized
KROHNE protocol, which allows all dynamic values and
setting parameters to be read and changed. If the BM 70
A/P is connected to existing user systems, this protocol
must be applied to such systems. The protocol can also
be used when the BM 70 A/P is connected to the KROHNE
Tank Inventory System. For further information, please
ask for the "BM70A/P PC Communication" description.
MODBUS:
(not yet included in V. 3.00/3.01/4.00)
The Modbus protocol constitutes a quasi-standard for
linking to progra mmable logic controls (PLC) and other
systems. The BM 70 A/P uses the Modbus RTU Protocol
with extended facilities to permit access to all dynamic
values and setting parameters. For further information,
please ask for the "BM70A/P Modbus" description.
PROFIBUS-PA:
(special signal output required)
The PROFIBUS-PA is defined and standardized in DIN
19245, Parts 1 and 2. A large number of devices with
PROFIBUS-PA capability are available on the market. The
BM 70 A/P is easy to connect to such bus systems; it has
a purely slave function and allows access to all dynamic
values and to setting parameters. The hardware interface
we use is the intrinsically safe bus interface.
For further information, please ask for the "BM70A/P
PROFIBUS-PA" description.
F.FOUND.:
(special signal output required)
Bus interface in conformity with the "Foundation Fieldbus"
(FF). For further information, please ask for the "BM70A/P
Foundation Fieldbus " description.
- in preparation -