Section 3 Serial Interface; Optional Serial Interface Board; Data Communications Format/Setup; Print Format - Hach EC1000 Instruction Manual

SECTION 3 SERIAL INTERFACE

3.1 Optional Serial Interface Board

3.2 Data Communications Format/Setup

3.3 Print Format

A serial interface board (Cat. No. 46326-00) is available as a user-installed option for the
pH/ORP Meter. The board enables the analyzer to be connected to a printer or a computer
to provide a permanent record of pH/mV levels and the occurrence of any alarm
conditions. Connection with a computer allows the computer to compile and store sample
pH/mV data and to control analyzer programming and operation from a remote location.
The interface board was designed primarily to permit direct connection of the analyzer
data output to an external printer. Interface with an external computer requires computer
programming to permit communication with and control of the analyzer. Due to the
variety of computer equipment and programming formats in use, this manual is written
for an operator knowledgeable about digital interface protocols and programming
requirements. The interface board can be set for two serial interface configurations:
standard RS-232C format or a current loop format.
Data communication format selections of baud rate, parity, word length and stop bits, are
set in the serial [I/O] submenu of the setup menu. Refer to Section 2.2.5 Initial Setup. The
factory default settings are: 1200 baud, no parity, 8 bit word length, 2 stop bits.
The serial I/O operates without handshake, therefore care must be taken to prevent loss
of data. During data transmission from the instrument, each character is sent at 53 ms
intervals. At the end of each line a 1.5 second delay is added. This delay is required for use
with many printers that have a one line buffer. The delay allows the printer time to print
the line before the next line is started. If the printer delay is not required, it is disabled in
the serial I/O submenu of the setup menu. On the receive data, no delays are required
between characters, but the receive buffer only holds one line. Therefore if more than one
command is being sent, the response from the first command must be completed before
the next command is sent.
The data print format is set for a 40-column print width. On power-up, (unless print
interval is set to 0) or on command, a data header is output to the printer (Figure 7).
The data header contains information about the analyzer setup. The data header may be
printed at any time by selecting the print listings.
See Figure 7 for:
•
a system warning (*W9*11*)
•
normal sample measurement (pH, MV, TEMP)
•
an activated alarm lockout (*ALO*)
•
setpoint alarms (*A1*)
•
manual temperature compensation indicator (M)
•
making a user calibration (pH OFFSET CAL)
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