Pc Communication - Hanna Instruments HI 504 Instruction Manual

PC COMMUNICATION

RS485 standard is a digital transmission method that allows
long lines connections. Its current-loop system makes this
standard suitable for data transmission in noisy environments.
Data transmission from the instrument to the PC is possible
with the HI 92500 Windows
ware offered by Hanna Instruments and an RS232 to RS485
adapter with Send Data Control connected to the serial port
of your PC.
The user-friendly HI 92500 offers a variety of features such
as logging selected variables or plotting the recorded data. It
also has an on-line help feature to support you throughout
the operation.
The readings logged into the HI 504 internal memory can
be downloaded through HI 92500.
HI 92500 makes it possible for you to use the powerful means
of the most diffused spreadsheet programs. Simply run your
favorite spreadsheet program and open the file downloaded
by HI 92500. It is then possible to elaborate the data with
your software (e.g. graphics, statistical analysis).
To install HI 92500 you need a 3.5" drive and few minutes
to follow the instructions conveniently printed on the disk's
label.
Contact your Hanna Dealer to request a copy.
SPECIFICATIONS
The RS485 standard is implemented in HI 504 with the fol-
lowing characteristics:
Data rate:
Communication:
Line length:
Loads:
Internal termination: none
Windows ® registered Trademark of "Microsoft Co."
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®
compatible application soft-
up to 19200 bps (manually selected)
Bidirectional Half-Duplex
up to 1.2 Km typ. with 24AWG cable
up to 32 typ.
CONNECTIONS
The connections for the 6-pin RS485 terminal provided are
as follows:
There is an internal short between the two A pins and be-
tween the two B pins.
The instrument has no internal line termination. To terminate
the line, an external resistor equal to the characteristic line
impedance (typically 120
the line.
The RS485 can connect up to 31 HI 504 on the same physi-
cal network. All the units are slave devices and are monitored
and controlled by a single master station (typically an indus-
trial PLC or PC).
Each HI 504 unit is identified by its Process ID number,
included in the 00 to 99 interval, which corresponds to the
Process ID configured through the setup item G.11.
(If the instrument does not recognize the address within the
command string, then it discards all the following bytes).
As additional feature, the controller is also provided with two
pins (5V and GND) in order to apply the Fail Safe Open Line
protection method. To avoid erroneous readings in Open-
must be added at both ends of
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