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(Reprint from Coast Writing press release 2005)
TAKING THE GAMBLE OUT OF EMBEDDED SYSTEMS DESIGN
Need an easy way to check new designs for faults and to monitor data and protocols?
There’s a practical little hand-held tool out called a DLM400 (Benedict
Computer, Menlo Park, CA), that does just that. This versatile device
tests, monitors, and analyzes transmissions, allowing instrumentation,
control, and automation design engineers to observe all traffic
between the host CPU and the device at the other end of the RS232 (or
similar) channel.
The DLM 400 is an RS232, RS422, RS485, RS530 or MIL-188C data
communications diagnostic and troubleshooting tool for designing
embedded serial devices and drivers into host processors. With it, the
developer views actual transmitted/received data along with associated
channel and control signals.
Easy to understand LCD prompts, and the supplied quick start set-up
guide, allow even a novice user to turn on the DLM400, view and set up
parameters, connect the unit to the channel for monitoring and display
transmitted/received data and protocols within a few minutes.
Design engineers find this device to be extremely useful during their
development phase. A case in point is Add-On Technologies
(Wingate, NC), builders of the DynaCash dispensing system -- a
PC-to-automated cash dispensing system (i.e. an indoor ATM for
improving security and productivity).
As depicted on the accompanying diagram, the standard system consists
of two Windows software front-end components (PCs) at a cashier or
teller station that perform text capture tasks and record the Cash Back
amount requested by the customers. Each PC then outputs the amount to
the LM-2000 router, via the PCs’ serial ports. The router box merges
the two serial port streams from the PCs into one stream for output to
the CC-1000, which drives the cash dispenser unit. The CC-1000 also
serves as a cash inventory control terminal, reporting to a journal
printer on a per-transaction basis. In addition, it manages security
(e.g., PIN numbers, cashier/teller numbers) for cash dispensing.
According to system designer Ray Van Vynckt, “The DLM 400 is employed
to monitor the complex protocols between our system and the cash
dispensers during development of the embedded dispenser driver.” The
diagram shows the insertion points where the DLM 400 is placed to
monitor channel protocol activity between hardware
units.
HOW IT WORKS
The unit’s operating panel consists of a full 64-key QWERTY keyboard
plus PC style directional keypad. Labels on the keys indicate the
operations to be performed. Three operating modes are available: Menu,
View and Execute.
The Menu mode provides the screen prompts to guide you through the
monitoring procedure, parameter settings and function selection. View
mode permits data and signal viewing. The data scrolls through the
display at one of four selectable viewing rates. An expanded view
option makes high-speed data transfers easier to see. The Execute mode
is the “do” (activate) mode; that’s all there is to it, -- “It’s pretty
simple to operate,” says Vynckt. .
With the DLM 400, Design Engineers perform fault checking of embedded
designs during the development phase, exercise hardware, and carry out
response-time monitoring of data communications between the host and
device. The unit is capable of observing transmitted and received data
flow over sync or async lines.
All prompts, menus, and configurable parameters are stored in a
nonvolatile memory; factory set defaults or the latest user-defined
selections are also safely stored for automatic recall. They can be
viewed on the unit’s LCD, consisting of eight rows of 30/40 characters
each.
Transmit and Receive buffers hold a total of 1MB of data (over 304,000
records). Data capture selection can be continuous (discarding the
oldest data or stopping when the buffers are full), or user-defined via
a selected character string acting as a trigger to start the
process. There are several modes and formats available for data
viewing, with transmitted and received data simultaneously displayed on
consecutive screen rows.
The DLM400 can transmit several different data patterns for continuous
output or BERT testing, and it utilizes any of five user-selected
protocols. Baud rates from 75 – 115,200 bps (230,400 bps
half-duplex) asynchronous and 75 to 64,000 bps synchronous are
supported. Transmit and receive data are displayed simultaneously in
various common formats, including the popular ASCII, EBCDIC, BAUDOT,
and IPARS.
This development tool weights only 23 ounces (including the battery)
and measures 9.25 x 5.50 x 1.37 inches. The hand-held device can be
operated from within its protective carrying case. Its nine-volt
alkaline battery provides 10 hours of power, eliminating the need to
locate an AC outlet, and makes the tool suitable for field use.
The DLM 400 provides engineers an in-depth look into the communications
line during embedded system development; all data transmissions and
protocol signals over an RS-232, RS422, RS485, or RS530 line are
observed. It is a developer’s tool for configuring new embedded
software designs, data line monitoring and testing, and for general
data communications troubleshooting and fault isolation.
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COMPUTER Homepage of
hand held RS232 / RS422 MONITORS
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