Brooks Instrument SLA5800 Series - Manual (Page 14)

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Brooks ® Digital MFC's & MFM's
Section 1 Introduction Installation and Operation Manual
X-TMF-SLA5800-MFC-eng
Part Number: 541B027AAG
April, 2013
RS-485 Communications
The Brooks Digital Series is equipped with RS-485 communication
capability. Refer to Table 1-3 (Analog I/O pin connections), that enables the
device to communicate via a personal computer for process control.
Baud rate selections for the Brooks Digital Series related to RS-485 are:
1200, 2400, 4800, 9600, 19200 and 38400 baud and can be selected via
the Brooks service Suite
TM .
The RS-485 is essentially a multidrop connection. It allows a maximum of
32 devices to be connected to a computer system. IBM-compatible PC's
are not equipped with RS-485 ports as standard. An RS-232 to RS-485
converter or RS-485 interface board is therefore required to connect an
RS-485 network to a standard pc. The RS-485 bus, a daisy chain network,
meaning that the wires are connected at the units as in Figure 1-2.
DEFAULT = CAL# 1 (External resistor not installed)
CAL Resistor Value (k ohms) CAL Resistor Value (k ohms)
1 Not Installed 6 124
2 Shorted 7 80.6
3 665 8 52.3
4 324 9 30.9
5 191 10 15
Table 1-3 Analog I/O Pin Connections:
Table 1-2 Calibration Select Signal.
Function PIN
Setpoint, Common Input (-) 1
Flow Signal, 0(1) -5 volt, Output (+) 2
TTL Alarm, open collector, Output (+) 3
Flow Signal, 0(4)-20 mA, Output (+) 4
Power Supply, +13.5 Vdc to +27 Vdc(+) 5
Not Connected 6
Setpoint, 0(4)-20 mA, Input (+) 7
Setpoint, 0(1)-5 Vdc, Input (+) 8
Power Supply, Common (-) 9
Flow Signal, Common, Output, (-) 10
Reference, +5 Vdc, Output (+) 11
Valve Override, Input 12
Calibration Select Input 13
RS-485 Common B (-) 14
RS-485 Common A (+) 15