User`s manual

Western Reserve Controls, Inc. 1782-JDC User’s Manual

5.1.10 Transmitting Serial Data

The use of a delimiter in transmitting data to a serial device from the JDC is determined by

the Max_Number_of_Transmit_Chars parameter. The operation is defined below.

If Max_Number_of_Transmit_Chars = 0 (Param. 5),

The JDC receives data sent from the DeviceNet Master and uses the delimiter to

determine how much data is sent to the serial device.

If a delimiter is contained within the string, then

 all characters up to and including the defined delimiter are sent to the ASCII

device

If no delimiter is contained within the string, then

 the JDC will send data received from the DeviceNet I/O command message to

the ASCII device

Note: If Max_Number_of_Transmit_Chars is zero, Byte-Swapping will not work.

If Max_Number_of_Transmit_Chars > 0 (Param. 5),

The JDC receives data sent from the DeviceNet Master ignoring any embedded

terminator. It will send the number of characters defined in

Max_Number_of_Transmit_Chars, or the total sent by the Master, whichever is less.

Note: Pad Mode is irrelevant to the ASCII transmit operation.

5.1.11 ASCII Receive Data and Pad Mode

The selection of Pad Mode is valid only for the ASCII receive and DeviceNet I/O Response

operation. It has no effect on DeviceNet I/O Command strings and ASCII transmit data to your

ASCII device.

The number of bytes returned to the DeviceNet Master in a Poll Response is as follows:

If Max_Number_of_Receive_Chars = 0 (Param. 5),

The expected operation is that the JDC receives characters (data bytes) until the

delimiter character is received

If a delimiter is received, then

 all characters up to and including the defined delimiter are sent to the DeviceNet

master

If no delimiter is received, then

 the JDC will receive data until the quantity of received bytes fills up its internal

buffer (124 bytes), and then sends the entire string to DeviceNet with an overflow

error

In this situation, the Pad Mode selection is irrelevant and no pad characters are added to the

data returned.

Note: If Max_Number_of_Receive_Chars is zero, Byte-Swapping will not work.