Pressure Systems 9046 - Manual (Page 47)

Pressure Systems, Inc. Model 9046 User’s Manual
Page 41 www.PressureSystems.com
5.7 Define/Control Autonomous Host Streams (Command ’c’)
Purpose : Defines and controls the autonomous delivery of up to three concurrent high-speed
autonomous data streams to the host computer. Such data streams may be delivered
"continuously" (i.e., unbounded, until a command explicitly stops them), or be delivered in a
"limited" amount (i.e., bounded, by a pre-specified fixed number of data scans to be sent). Each
scan delivered may be synchronized by a user-supplied "hardware trigger" or each scan may
be delivered periodically as synchronized by an internal software clock. These concurrent host
streams are an alternate method of acquiring/delivering data rather than the host using the
many other special purpose "read" commands (’
V’, ’a’, ’b’, ’r’, ’t’, ’m’, and ’n’) for reading various
data values in various formats.
Host data streams, once activated in a module, normally deliver a sequence of TCP/IP
(optionally UDP/IP) data scans autonomously to the host (i.e., without the host sending any
particular command to the module to request each scan).
Note
If data streams are defined to occur at high scan rates, then each
data scan received by the host must be processed and disposed of
in a timely manner. Model 9046 modules are capable of generating
autonomous data streams faster than some "slow" hosts (or limited
software, including NUSS) can absorb.
Various sub-commands (described on the following pages) are used to identify the various
definition and control options of the following general ’c’ command.
Command "c ii[ dddd] ... "
’c’ is the operation code
’ ii’ is a space followed by a sub-command index
(augment code).
’ dddd’ are one or more optional datum fields, each
preceded by a space character; These
parameters differ for each sub-command.
NOTE: all parameters are preceded by a space,
including the first hex parameter (ii) - which is
unlike most other commands which attach the first
parameter(s) to the operation code.
Response Depends upon particular sub-command (’ ii’) sent.
See below.
Autonomous
Packet Depends upon the particular sub-command (’ ii’)
sent. See below.