Table of Contents
Advertisement
PRODUCT INSTALLATION MANUAL
3.5. M
O
ODES OF
PERATION
SCAN MODE - This command sent to the MUX 2700 from the software will instruct the MUX to periodically
scan each device automatically. Normally the MUX 2700 will only communicate with a device when
instructed by the software.
BURST MODE – This command instructs the field device to automatically send information without being
commanded to do so. This mode breaks from the normal master-slave relationship inherent in HART
communication, but the MUX 2700 will support it when burst mode is selected in the software.
3.6. S
O
YSTEM
PERATION
Referring to Figure 6, the heart of the MUX 2700 is the microprocessor. One serial port together with the
HART modem generates the physical layer of the HART protocol, while the channel select circuit together
with the channel multiplexer links one specific channel (device) at a time. An RS-485 circuit completes the
link between the maintenance workstation PC and the field devices. The switch selectable circuit provides
information required by the MUX 2700 for initialization and configuration; specifically, the baud rate for
communications to the maintenance workstation PC and the MUX 2700 address.
Channel 1
M
U
L
T
I
P
L
E
X
E
R
Channel 32
Figure 6 – MUX Operation
1700 MUX Block diagram
MUX 2700 Block
USER
SWITCHES
MICROPROCESSOR
CHANNEL
SELECT
HART
MODEM
SERIAL PORTS
DOCT-B3K7
From the
Maintenance
Workstation
RS-485
(Through the
CIRCUIT
RS-485/232
Converter)
P
18
21
AGE
OF
Advertisement
Table of Contents
