Keithley 2601B Reference Manual page 221

Section 3: Functions and features
To write-protect specific digital I/O lines to prevent their values from being changed:
1. Press the MENU key, then select , and then press the ENTER key or the navigation wheel
2. Select WRITE-PROTECT, and then press the ENTER key or the navigation wheel
3. Set the decimal value as required to write-protect digital I/O lines within the range of 0 to 16,383
(see Digital I/O bit weighting
wheel
For example, to write-protect digital I/O lines 4 and 10, set the value to 520.
4. Press the EXIT (LOCAL) key as needed to return to the main menu.
To remove write protection, reset the decimal value to include only the lines that you want to write
protect. To remove write protection from all lines, set the value to 0.
Digital I/O bit weighting
Bit weighting for the digital I/O lines is shown in the following table.
Digital bit weight
Line # Bit
1 B1
2 B2
3 B3
4 B4
5 B5
6 B6
7 B7
8 B8
9 B9
10 B10
11 B11
12 B12
13 B13
14 B14
Remote digital I/O commands
Commands that control and access the digital I/O port are summarized in the following table. See the
TSP command reference
table for decimal and hexadecimal values used to control and access the digital I/O port and
individual lines. Use these commands to trigger the Series 2600B using external trigger pulses
applied to the digital I/O port, or to provide trigger pulses to external devices.
Use these commands to perform basic steady-state digital I/O operations such as reading and writing
to individual I/O lines or reading and writing to the entire port.
The digital I/O lines can be used for both input and output. You must write a 1 to all digital I/O lines
that are to be used as inputs.
3-86
(on page 3-86)), and then press the ENTER key or the navigation
.
Decimal weighting Hexadecimal weighting
1 0x0001
2 0x0002
4 0x0004
8 0x0008
16 0x0010
32 0x0020
64 0x0040
128 0x0080
256 0x0100
512 0x0200
1,024 0x0400
2,048 0x0800
4,096 0x1000
8,192 0x2000
(on page 7-1) for complete details on these commands. See the following
Series 2600B System SourceMeter® Instrument Reference Manual
.
2600BS-901-01 Rev. B / May 2013
.