Rockwell Automation 20-COMM-S RS-485 DF1 Adapter - Manual (Page 51)

Glossary
A
Adapter
Devices such as drives, controllers, and computers usually require an
adapter to provide a communication interface between them and a
network such as RS-485 DF1. An adapter reads data on the network and
transmits it to the connected device. It also reads data in the device and
transmits it to the network.
The 20-COMM-S adapter is an adapter that connects, PowerFlex drives
to a RS-485 DF1 network. Adapters are sometimes also called “cards,”
“embedded communication options,” “gateways,” “modules,” and
“peripherals.”
B Block Check Character (BCC)
A technique for error detection in data communications. A character is
added to a transmission block, which is compared with a second BCC
computed by the receiver to determine if the transmission is error free.
C
Controller
A controller, also called programmable logic controller, is a solid-state
control system that has a user-programmable memory for storage of
instructions to implement specific functions such as I/O control, logic,
timing, counting, report generation, communication, arithmetic, and data
file manipulation. A controller consists of a central processor, input/
output interface, and memory. See also Scanner.
Cyclic Redundancy Check (CRC)
A commonly used technique for error detection in data communications.
A polynomial algorith is performed on the data, and the resultant
checksum is appended at the end of the frame. The receiving device
performs a similar algorithm.
D
Data Rate
The data rate is the speed at which data is transferred on the RS-485 DF1
network.
Each device on a RS-485 DF1 network must be set for the same data
rate. You can set the RS-485 DF1 adapter to 1200, 2400, 4800, 9600,
19.2K, or 38.4 kbps.