HP E1351A, User Manual

Page: 93 / 107

Register-Based Programming for Maximum Speed
This is an outline of the algorithm that needs to be followed to have the
HP E1326B 5
1
⁄
2
Digit Multimeter do high-speed scanning using the
HP E1351A 16-Channel FET Multiplexer. This procedure programs
the multimeter and downloads a scan list to the FET multiplexer so the
hardware controls the entire scanning process. The HP E1326B has several
things that should be understood when doing register programming.
1. Table B-1 on page 96 lists the multimeter’s commands. When doing
any of these commands, you are writing to registers which are read by the
multimeter’s voltmeter microprocessor. It is important to follow the
procedure in Figure B-3 on page 97 on how to send commands. This will
enable you to handshake with the E1326B microprocessor as you can easily
write commands faster than the processor can execute them.
2. In order to program the HP E1326B Multimeter to take readings with
the HP E1351A FET Multiplexer at its highest speed, do the commands
from Table B-1 on page 96. Note that all values in Table B-1 are specified
in decimal.
set the function dcv
set the range 1V
Note: You must have a fixed range to do 13k. Auto range will do 2.5k
.
set the aperture 10
µ
sec
Note: This will cause readings to be returned as 16 bits.
set the auto zero
off or once
set offset Compensation off
set trigger source Immediate
set trigger count 1
set trigger delay 0
set Sample Count 16
This should be the total number of A/D readings that you will take
(for example, once through a 16 channel list = 16, 10 times through
a 16 channel list = 160).
set sample Source
Timer
This is the time between A/D readings.
set sample Period
76
µ
s
76
µ
sec is the minimum or fastest A/D time.
set trigger arm armed
This arms the DVM to take all of the reading specified above.
Do not execute the next command yet. You still need to set the scan list in
the HP E1351A. Trigger immediate will start everything.
3. Now download the channel list to the HP E1351A
•
Set CLR SCN in Scan Control Register to one, then back to zero in
order to clear the previous scan list.
•
DIR in the Status/Control Register set to false.
Appendix B HP E1351A/53A Register-Based Programming 93