MSI-9000 CellScale
®
System • 3750CS User Guide Page 59
MEASUREMENT SYSTEMS INTERNATIONAL
Software V1-15 to 1-20
SECTION 9 – COMMUNICATION PORTS
INTRODUCTION
• The MSI 3750CS is equipped with a single RS-232 serial input/output and a Real Time Clock/Calendar. The
Comm Port is intended for interfacing printers, data loggers, scoreboards, and computers to the 3750CS Meter.
The real-time clock allows the user to time and/or date stamp any data obtained from the 3750CS.
• The data output is fully format able. The 3750CS, under menu control will print control characters for
easy interfacing to any label printer. An initialize string combined with start string, product labels, user
programmable data, weight data, and end strings, provides complete control over printed data.
• Many scales and weigh meters suspend weighing operation while printing and will not function until a print
job is completed. The MSI 3750CS RS-232 output uses advanced DMA (direct memory access) techniques for
transmitting the print strings. This prevents long print jobs from interfering with scale operation.
Comm Port Function
The RS-232 output is used in conjunction with the PRINT key to output weight and total data to a printer
or can be used for bi-directional communications with a computer, allowing full computer control of scale
functions. In addition there are several automatic print modes including print on Total, when there is a weight
change, or when a set point is reached. Interval and continuous printing is available for data logging or
interfacing Scoreboard displays.
Comm Port 2 is dedicated to RF Communications and not accessible for user programming. However, Modem
parameters and diagnostic menus are available.
ELECTRICAL CONFORMANCE
The electrical characteristics of the serial input/output conform to the EIA Standard EIA-232-D (downward
compatible with RS-232C). Comm Port 1 is configured as DCE. Cable connections include RXD (input), TXD
(output), Ground, CTS (input), RTS (output), and Shield Ground (also known as Frame Ground). CTS/RTS
handshaking is optional and the lines do not need to be connected
COMM PORT CABLING
3750CS units have a water-proof connector on the rear panel. This connector mates with MSI P/N 12023
which provide unterminated wires, or MSI P/N 501705-0001 which provides a standard 9 pin “D” connector
termination.
Unterminated wire assignments are: Brown – TXD (output), Black – RXD (input), White – CTS (input), Grey
– RTS (output), and Blue is Signal Ground.
DATA CONFIGURATION
The 3750CS serial port options are configured with the “COMPORT” Menus. Standard data configuration is:
Data String Buffers
A Data String is simply a collection of characters stored in memory, that are used to format the Comm
Port output. Data Strings are defined by the user. The length of the formatting strings are limited to 255
characters.. However, since 3 or 4 character commands can cause an output of up to 99 characters in length,
the 255 limit does not represent the maximum size of the data output. The 3750CS offers the programmer
the ability to print any and all weight data, time and date stamp, and formatting controls suitable for even
the most complex bar code printer.
Data Format
Each transmitted reading consists of a number of programmable character strings. Data is completely user
programmable and can include formatting characters and text in addition to all weight parameters. The
End-of-Line string is used for Carriage Return or other end-of-line control characters. These are easily entered
through the Comm Port menu or downloaded through a computer.
OUTPUT CONTROL
The MSI 3750CS serial port functions in any of 10 modes:
1) Front Panel Print Key:
This is a print on command mode which works when the print button on the front panel is pushed. The Print
