Rs 485 Communication - Hanna Instruments mV 602 Series Instruction Manual

RS 485 COMMUNICATION

pH502XY2, pH502XY3, mV602XY2 and mV602XY3 are pro-
vided with an RS485 port.
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.
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.
HI 92500 makes it possible for you to use the powerful means
of the most diffused spreadsheet programs (Excel
1-2-3 © etc.). Simply run your favorite spread sheet and open
the file downloaded by HI 92500. It is then possible to elabo-
rate 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 pH502/mV602 with
the following characteristics:
Data rate:
Communication:
Line length:
Loads:
Internal termination: none
Excel © Copyright of "Microsoft Co."
©
Lotus 1-2-3 Copyright of "Lotus Co."
®
Windows registered Trademark of "Microsoft Co."
28
® compatible application soft-
©
, Lotus
up to 9600 bps
Bi-directional 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 (#1
on page 7) 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.
Up to 32 units can be connected to the same RS485 line,
with a total line length of up to 1.2 Km using 24AWG cable.
To minimize electromagnetic interferences, use shielded or
twisted pair cable to connect the units.
Each pH502/mV602 unit is identified by its process ID num-
ber (setup item "01").
The pH502/mV602 controller acts as a "slave" device: it
only answers to commands received from a "master" device
(e.g. an industrial PC) connected to the line.
must be added at both ends of
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