Keithley 6485 User Manual

10-6 Status Structure Model 6485 Picoammeter Instruction Manual
Figure 10-2
16-bit status register
Reading registers
Any register in the status structure can be read by using the appropriate query (?) com-
mand. The following explains how to interpret the returned value (response message). The
actual query commands are covered later in this section (Table 10-3 through Table 10-6).
The response message will be a value that indicates which bits in the register are set. That
value (if not already binary) will have to be converted to its binary equivalent. For exam-
ple, for a binary value of 100101, bits B5, B2, and B0 are set.
The returned value can be in the binary, decimal, hexadecimal, or octal format. The FOR-
Mat:SREGister command is used to select the data format for the returned value
(Table 10-2).
For non-decimal formats, one of the following headers will accompany the returned value
to indicate which format is selected:
#B = Header for binary values,
#H = Header for hexadecimal values,
#Q = Header for octal values
B7
B15
B6 B5
B4
B3
B2 B1
B0
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
128
(2 )
7
32768
(2 )
15
64
(2 )
6
16384
(2 )
14
32
(2 )
5
8192
(2 )
13
16
(2 )
4
4096
(2 )
12
8
(2 )
3
2048
(2 )
11
4
(2 )
2
1024
(2 )
10
2
(2 )
1
512
(2 )
9
1
(2 )
0
256
(2 )
8
Bit Position
Bit Position
Binary Value
Binary Value
Decimal Weights
Decimal Weights
A. Bits 0 through 7
B. Bits 8 through 15
B14 B13 B12 B11 B10 B9 B8

Keithley 6485 Specifications

General

Model	Keithley 6485
Category	Picoammeter
Input Impedance	>10^14 Ohms
Voltage Burden	<200µV
Accuracy	0.4% of reading
Voltage Source Range	Not Applicable
Voltage Source Resolution	Not Applicable
Voltage Source Accuracy	Not Applicable
Interface	IEEE-488
Power Requirements	100V to 240V AC, 50/60Hz
Dimensions	89 mm high x 214 mm wide x 369 mm deep (3.5 in x 8.4 in x 14.5 in)