National Instruments NI-488.2 ユーザーズマニュアル

© National Instruments Corporation

This chapter describes techniques for using some NI-488.2 calls in your 
application. 

For more information about each function, refer to the NI-488.2 online 
help. For instructions on accessing the online help, refer to the 

 section in 

GPIB data transfers are terminated either when the GPIB EOI line 
is asserted with the last byte of a transfer or when a preconfigured 
end-of-string (EOS) character is transmitted. By default, EOI is asserted 
with the last byte of writes and the EOS modes are disabled.

You can use the 

ibeot

 function to enable or disable the end of transmission 

(EOT) mode. If EOT mode is enabled, the GPIB EOI line is asserted when 
the last byte of a write is sent out on the GPIB. If it is disabled, the EOI line 
is not asserted with the last byte of a write.

You can use the 

ibeos

 function to enable, disable, or configure the EOS 

modes. EOS mode configuration includes the following information:

•

A 7-bit or 8-bit EOS byte.

•

EOS comparison method—This indicates whether the EOS byte has 
seven or eight significant bits. For a 7-bit EOS byte, the eighth bit of 
the EOS byte is ignored.

•

EOS write method—If this is enabled, the GPIB EOI line is 
automatically asserted when the EOS byte is written to the GPIB. If the 
buffer passed into an 

ibwrt

 call contains five occurrences of the EOS 

byte, the EOI line is asserted as each of the five EOS bytes are written 
to the GPIB. If an 

ibwrt

 buffer does not contain an occurrence of 

the EOS byte, the EOI line is not asserted (unless the EOT mode is 
enabled, in which case the EOI line is asserted with the last byte 
of the write).