3-6
Brooks
®
Model SLA5840
Section 3 Operation
Installation and Operation Manual
X-PR-SLA5840-Series-RevB-RT-eng
Part Number: 541B201AAG
October, 2017
This will result in calibration inaccuracy during normal operation.
Once zero differential pressure is established and verified, press the
recessed, momentary push-button (self-zero button) located on the side of
the device
(See Figure 3-5) to start the self-zero function. The zeroing process
requires approximately 200 mseconds.
3-5 Communications Features
3-5-1 Analog/RS485 Communications Features
Digital communication, designed to emulate the Brooks S-series "S-
protocol" or pseudo-HART communications is available on the Brooks
Digital Series via RS485. This form of multi-drop capable communication
provides access to many of the Brooks Digital Series functions for "control
and monitor" operations, including:
•
Accurate setpoint adjustment flow output measurement
(including units of measure selection)
•
Valve Override (controller only)
•
Flow Totalizer
•
Alarm status and settings
•
Soft Start Control (controller only)
RS485 equipped units support the following baud rates. Please specify the
desired baud rate when ordering (default is 19200 baud). Alternately, baud
rate may be changed using the Brooks Expert Support Tool (BEST).
Baud Rates: 1200, 2400, 4800, 9600,
19200
and 38400
Reference the Brooks document "Supplemental Manual for RS485
Communications for Brooks
®
MFCs/MFMs/PCs/RTs for SLA5800/SLAMf
Revsion B Series" (X-DPT-RS485-SLA5800-SLAMf-Series-RevB-MFC-
PC-RT-eng) for more details regarding the capabilities of this
communication interface.
3-5-2 Profibus Communications Features
The Brooks SLA5840 is now equipped to support the Profibus
communication protocol.
The communication electronics allows for automatic baud rate detection
ranging from 9600 baud to 12 Mbaud, thus making the need for any
hardware baud rate selection methods not required. For selecting the
device address, which must be unique on the network, two rotary switches
are provided. This allows a user to easily select any address number
ranging from 0 to 126. This can provide fast device replacement without
complex network configurations. The device is equipped with a zero
command pushbutton, allowing the user to give a manual command to the
device to (re)balance the flow sensor electronics. This command can also
be issued through the protocol.
