Keithley 7707, User Manual

Page: 43 / 59

40
:DWORd? <clist> Read input double-word pattern
Use to read a 32-bit input pattern (double-word) present on the four input ports. Input channel 11 is read to return the 32-bit
pattern. Channel 11 is combined with channels 12, 13, and 14 to form one 32-bit pattern.
NOTE
Only channel 11 is valid with the :DWORd command. Using any other channel with the command
generates error -221 (settings conflict).
When reading a double-word bit pattern, all I/O channels (11, 12, 13, and 14) must be configured
as input ports. Otherwise, error -221 (settings conflict) will occur when the :DWOR command is
sent.
When channel 11 is read as a double-word, Bit 0 (B0) of channel 11 will be the LSB, and Bit 7 (B31) of channel 14 will be the
MSB. Bit positions for a double-word are shown in
Figure 18 .
An input pattern can be returned in the decimal, binary, hexadecimal, or octal format. For non-decimal formats, one of the
following headers will accompany the returned value to identify which format is selected:
#B = Header for binary values
#H = Header for hexadecimal values
#Q = Header for octal values
Use the :FORMat command to select the format for reading input patterns.
Example: Assume bit pattern “00000001 00110010 00001001 00010101” is present on channels 11, 12, 13, and 14. The
following commands will read the double-word input pattern using the binary format:
OUTP:DIG:STAT 0,(111:114)
' Set channels 11, 12, 13, and 14 as input ports.
SENS:DIG:FORM BIN,0
' Select binary format (no leading zeroes).
SENS:DIG:WORD? @111)
' Read word bit pattern.
The returned response message will be “#B1001100100000100 00010101” to indicate that Bits B0, B2, B4, B8, B11, B17,
B20, B21, and B24 are set to TTL high (logic ‘1’). The rest of the byte bits are set low (logic ‘0’).
ROUTe:SCAN <clist> Specify scan list
ROUTe:SCAN? Query scan list
Use the ROUTe:SCAN <clist> command to add digital channels to a scan list. However, the digital channel must first be
configured as an input channel. If you send this command to add a channel that is presently configured as an output channel,
error -221 (settings conflict) will occur.
The following command sequence shows how to set channel 112 as an input channel and then add it to a scan list that already
contain channels 101 through 110:
OUTPut:DIGital:STATe 0,(@111)
‘ Set channel 111 as an input channel.
ROUTe:SCAN (@101:110,111)
‘ Add channel 111 to scan list.
A digital input channel cannot be included in a range of scan channels when configuring a list. Digital input channels must be
listed individually. The following examples show the right and wrong ways to add a digital input channel to a scan list.
ROUTe:SCAN (@101:110,111)
‘ Correct way to add channel 111 to scan list.
ROUTe:SCAN (@101:111)
‘ INVALID – Error -222 (Parameter data out of range).
NOTE For details on scanning, see Section 7 of the Model 27xx User’s Manual.