HF scientific Micro200BW Turbidimeter - 0-100 NTU - Manual (Page 52)

MICRO 200 BW 0-10 & 0-100 NTU (05/05)
Rev. 3.4
8.0 OPTIONS - Continued
SERIAL INTERFACES
8.6 SERIAL INTERFACES
Each of these options maybe installed by removing the
rear cover of the analyzer as shown in figure 8 on page
10 and plugging in the interface as shown in figure 23.
Figure 23
Serial Interface Installation
These options may be used to connect to a serial printer,
a data logger or as a direct interface to a computer. The
serial port will report each reading that is seen on the
analyzer digital display. The protocol is 8 bits, no parity,
1 stop bit. The baud rate is screen selectable. The report
is in ASCII format and is concluded with a carriage
return and line feed.
As an example, if the display of the MICRO 200 BW
reads 0.1234 NTU, the serial port decimal string would
be:
Decimal
48 46 49 50 51 52 78 84 85 13 12
0 . 1 2 3 4 N T U (CR) (LF)
ASCII
(SP) = Space; (CR) = Carriage Return; (LF) = Line Feed
If the display reads 098.7 % T, the serial port decimal
string would be:
Decimal
48 57 56 46 55 0 37 84 13 12
0 9 8 . 7 (SP) % T (CR) (LF)
ASCII
By selecting “Printer on” via the Main Menu, Utility
Menu and the COMM Port menu, the MICRO 200 BW
will transmit each reading, in real time. This mode is
used to drive a printer for raw data collection.
By selecting “Printer Off” the MICRO 200 BW will
only transmit its reading by command. Up to 16 MICRO
200 BW units may be simultaneously connected to one
serial port of a host computer. An address may be
assigned to a particular unit by operating F2 in the
Comm Port Menu. It will serially cycle through ad-
dresses 0 through F (Hexadecimal). Obviously, no two
units, which are on the same host computer port, should
have the same address.
If the host computer transmits the ASCII character “@”
(decimal 64) followed by the ASCII character address,
for instance, 64, F, only the unit assigned address “F”
will respond with its reading. This allows data logging
for a non-dedicated host computer for up to 16 MICRO
200 BW units on only one of its serial ports. Both the
MICRO 200 BW and the host computer must be set at
the same baud rate. The host computer requires soft-
ware to handle the data storage.
8.6.1 RS-232C Standard Voltage Mode Interface
(Catalog # 19861)
This configuration is the standard serial port format
(RS-232C). It is suitable where the cable length be-
tween the most remote MICRO 200 BW analyzer and
the host computer does not exceed 50 feet (16.4 m.).
Due to it’s “tri-state transmitter” design, the companion
MICRO 200 BW units, which are on the same serial port
at the host computer, may be “hubbed” or connected
each one to the next as long as the total cable length from
each MICRO 200 BW to the host computer does no
exceed 50 feet (16.4 m.). See figure 24 on page 42.
TXD = Pin #1; Transmitted data out; Data to computer
or printer
GRD = Pin #5; ground; digital common
RXD = Pin #8; received data in; data from computer to
MICRO 200 BW
Please consult HF scientific, inc. for more detailed
instructions.
8.6.2 RS-485 Half Duplex Interface
(Catalog # 19851)
This option may be used where the distance from the
host computer to the most remote MICRO 200 BW
analyzer is, in extreme cases, up to 10,000 feet (3.28
km), depending on the site noise conditions. It is similar
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