Communicating with Devices on a Serial Link

10-13

 

 

This field

Specifies

Configure by Doing the Following

User mode char.

The character for the mode attention

 

character (above)

Enter a valid attention character. If the attention character you want to use is a control character, specify the ASCII equivalent.

When the controller encounters the attention character and the user mode character, the controller sets channel 0 communication to user mode. Note that the remote mode change option must be ENABLED.

Serial Settings

Baud rate

Communication rate for channel 0

Select 110, 300, 600, 1200, 2400, 4800, 9600, or 19.2k bps.

 

Configure all devices in the system for

 

 

the same communication rate

 

 

 

 

Parity

Parity setting for channel 0

Select NONE or EVEN.

 

Parity provides additional message

 

 

packet error detection.

 

 

 

 

Bits per character

Select the number of bits that make up

Select 7 or 8.

 

a transmitted character.

 

 

 

 

Error detect

Whether you want error detection set

Select one of the following:

 

to BCC or CRC

BCC: the controller sends and accepts messages that end with a BCC byte

 

 

 

 

for error checking. BCC is quicker and easier to implement in a computer

 

 

driver.

 

 

CRC: the controller sends and accepts messages with a 2-byte CRC for

 

 

error checking. CRC is more complete checking

 

 

Configure both stations to use the same type of error checking.

 

 

 

Stop bits

Match the number of stop bits to the

Select 1, 1.5, or 2.

 

device with which you are

 

 

communicating

 

 

 

 

Control line

Select the mode in which the driver

 

operates.

Select a method appropriate for your system’s configuration:

If you are not using a modem, choose NO HANDSHAKING.

If you are using a full-duplex modem, choose FULL-DUPLEX.

Option Settings

Station address

The node’s address on the DF1 link

Enter a valid DF1 station address. Valid station addresses are: 0-376

 

 

octal

 

 

 

DF1 retries

The number of times a message is

 

retried before being declared

 

undeliverable

Enter a valid value 0-255.

RTS send delay

The time delay between the time the

 

RTS is asserted and the beginning of

 

the message transmission

 

This time allows the modem to

 

prepare to transmit the message.

Enter a value 0-255. Limits are defined in 20 ms intervals. For example to wait 40 ms, type 2. The recommended time elapse is 0, unless you are using a modem that automatically returns the CTS as soon as it receives the RTS. If this is the case, enter a delay time to make sure the modem is able to transmit before it attempts to send the message.

Publication 1785-UM012D-EN-P - July 2005

Page 163
Image 163
Bradley Smoker PLC-5 user manual Octal, Retried before being declared, Enter a valid value RTS send delay