Rockwell Automation MD60 Serial Converter Module - M/N MDCOMM 232 - Manual (Page 47)

Glossary Glossary-1
G
LOSSARY
application code - Code that runs in the module after the boot
code calls it. It performs the normal operations of the system.
block check character (BCC) - An error detection scheme where
the 2s complement of the 8-bit sum (modulo-256 arithmetic sum) of
all data bytes in a transmission block. It provides a means of
checking the accuracy of each message transmission.
boot code - Code that runs when the module first receives power. It
checks basic operations and then calls the application code.
cyclic redundancy check (CRC) - An error detection scheme
where all of the characters in a message are treated as a string of
bits representing a binary number. This number is divided by a
predetermined binary number (a polynomial) and the remainder is
appended to the message as a CRC character. A similar operation
occurs at the receiving end to prove transmission integrity.
DF1 protocol - A peer-to-peer link layer protocol that combines
features of ANSI X3.28-1976 specification subcategories D1 (data
transparency) and F1 (two-way simultaneous transmission with
embedded responses).
DF1 rate - A unit of signaling speed equal to the number of discrete
conditions or signal events per second. It is also called baud rate or
serial port rate.
EEPROM - See non-volatile storage.
Flash update - The process of updating firmware in a device.
hold last - When communications are disrupted (for example, a
serial cable is disconnected), the converter and product can
respond by holding last state. Hold last state results in the product
receiving the last data received via the DF1 connection before the
disruption. If the product was in RUN mode and using the reference
from the converter, it will continue to run at the same reference.
Master - The Master command is capable of asserting or controlling
an operation on a segment according to protocol.
non-volatile storage (NVS) - NVS is the permanent memory of a
device. Devices such as the converter store parameters and other
information in NVS so that they are not lost when the device loses
power. NVS is sometimes called EEPROM.