Allen-Bradley 825-P, User Manual

Page: 164 / 266

164 Rockwell Automation Publication 825-UM004D-EN-P - November 2012
Chapter 12 ASCII Serial Communications
The 825-P front-panel serial port supports EIA-232 communication of ASCII
text data. Table 97 shows relay serial port settings for the front-panel port. Set the
Baud Rate, Data Bits, Parity, and Stop Bits settings to match the serial port
configuration of the equipment that is communicating with the serial port.
After Port Timeout minutes of inactivity on a serial port at Access Level 2, the
port automatically returns to Access Level 1. This security feature helps prevent
unauthorized access to the relay settings if the relay is accidentally left in Access
Level 2. If you do not want the port to time out, set Timeout equal to 0 minutes.
The relay EIA-232 serial ports support software (XON/XOFF) flow control. If
you want to enable support for hardware (RTS/CTS) flow control, set the Enable
Hardware Handshaking setting equal to Y.
Using Terminal Commands
When you type commands at the terminal emulation window, type either the
entire command or just use the first three letters (e.g., the following commands
instruct the relay to display metering data):
Type
METER
(or
MET
)
and press Enter.
Use upper- or lower-case characters when typing commands; however, password
entry is case sensitive. Table 99 lists user commands that the relay accepts at the
EIA-232 serial port.
The relay serial port uses software flow control, meaning that character
transmission is controlled by receipt of XON and XOFF characters. When the
relay receives the XOFF character during transmission, it pauses until it receives
an XON character. If a message is not in progress when the relay receives the
XOFF character, it blocks transmission of a message presented to its buffer.
Messages are transmitted after the relay receives the XON character.
You can send control characters from most keyboards using the keystrokes listed
in Table 98.
Table 97 - Front Panel Serial Port Settings
Setting Prompt Setting Range Factory Default
SPEED 300–38400 bps 9600
DATA BITS 7, 8 bits 8
PARITY O, E, N N
STOP BITS 1, 2 bits 1
PORT TIMEOUT 0–30 min 15
HDWR HANDSHAKING Y, N N