Agilent Technologies 34970A, User Manual, Page: 151 / 356

151
Chapter 4 Features and Functions
Digital Input Operations
4
Digital Input Operations
The multifunction module (34907A) has two non-isolated 8-bit input/
output ports which you can use for reading digital patterns. You can read
the live status of the bits on the port or you can configure a scan to
include a digital read.
• The digital input channels are numbered “ s 01” (lower byte) and “ s 02”
(upper byte), where s represents the slot number.
• You can generate an alarm when a specific bit pattern or bit pattern
change is detected on an input channel. With the multifunction
module, the channels do not have to be part of the scan list to
generate an alarm. For more information, see “Using Alarms With the
Multifunction Module” on page 148.
• When you add a digital read to a scan list, that port is dedicated to
the scan. The instrument issues a Card Reset to make that port an
input port (the other port is not affected). While included in the scan
list, you can still perform low-level read operations on the port, but
you cannot perform write operations on the port.
• From the front panel, you can read data from only one 8-bit input port
at a time. From the remote interface, you can read both ports
simultaneously as a 16-bit word only if neither port is in the scan list.
If one or both ports are included in the scan list, you can read only one
8-bit port at a time. However, if you have included both ports in the
scan list, the data will be read from both ports simultaneously and
will have the same time stamp. Therefore, you can externally
combine the two 8-bit quantities into a 16-bit quantity.
• From the front-panel only, you can specify whether you want to use
binary or decimal format (readings are always stored in memory in
decimal format). Once you have selected the number base, it is used
for all input or output operations on the same port.
• You can monitor a digital input channel even if the channel is not
part of the scan list (the internal DMM is not required either).
34970A Refresh UG.book Page 151 Wednesday, February 17, 2010 12:34 PM