BERTHOLD TECHNOLOGIES LB 480, User Manual

Page: 362 / 450

54733-10BA2L
3 – 362
02.2017
Menu Structure Volume 3
2.34
HART Interface
Menu path: Device Config

Setup

I/O Setup

HART
Interface .
1 Poll Addr
Shows the current polling address. The address can be set with Set
Poll Address .
2 Set Poll Address
Allows you to set the polling address for multidrop operation.
Enter only a polling address > 0 if the multidrop mode is used to
operate several HART
®
devices at one current loop. Otherwise,
leave the value at 0, since with a polling address > 0 the current
output has no function anymore.
To use the multi-drop mode the current output must be passive
(sink mode).
Multidrop mode
The host terminal uses the multidrop mode to identify the field
device if more than one HART
®
device is connected to the same
HART
®
loop. From HART
®
6, up to 63 HART
®
devices can be inter-
connected in one HART
®
loop. Each device must have a different
polling address between 1 and 63.
If an address is set which is higher than 0, the Multidrop Mode is
selected automatically and the current output is switched to a fixed
current value of 4 mA. Then only the digital HART
®
communication
will be available.
IMPORTANT
For safe HART
®
communication, the current output must have a
minimum impedance of 250ohms and a maximum impedance of
500ohms.
3 Num Req Preams
Display of the requested preambles during communication between
detector and communicator to initiate the start of communication.
The value is set to 3 and cannot be changed.
4 Num Resp Preams
Number of returned preambles during communication between
detector and communicator to initiate the start of communication.
The default value is 5. At a higher number, the communication is
slowed down slightly. The setting range is 5 to 20.