Rockwell-automation 1799-DASCII DeviceNet Serial Interface Manuale Utente Scaricare il pdf (Pagina 30)

30 DeviceNet Serial Interface Module

Publication 1799-IN012B-EN-P - July 2008

Transmit Serial Data to the ASCII Device

Read this section for information about transmitting serial data to the ASCII device.

Set Up the Transmit-character Buffer Length (parameter 19)

The Transmit-character buffer length is the number of characters that the

1799-DASCII module can receive in its transmit buffer from the DeviceNet system.

This size contributes to the I/O's Consume Size. This size can be found in the

Parameter object.

Set Up and Use the Transmit Delimiter (parameters 20 and 21)

The transmit delimiter is an end-of-string character that is used by the 1799-DASCII

module to determine how many bytes to transmit over the serial link to the

1799-DASCII device. This transmit delimiter is used if the Transmit Buffer Length

equals 0. If the buffer length is not 0, the 1799-DASCII module ignores the transmit

delimiter.

The 1799-DASCII module transmits up to and including the delimiter when the

above condition is met. The transmit delimiter can be set to any valid I/O character

that can be received over the link (parameter 21). Be careful not to set the

delimiter to a value outside of the valid range for the number of data bits. (Note

that a data bit size setting of 7 lets a delimiter range of 0…127 dec., 00…7Fhex). If

the delimiter is not valid, or the delimiter is never received, the device updates the

output buffer on detection of a buffer filled condition. These values can be set and

retrieved by using the standard set/get services in the Transmit Record Class 0x71.

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Rockwell-automation 1799-DASCII DeviceNet Serial Interface Manuale Utente Pagina 30