Pressure Systems 98RK DEFINE/CONTROL Autonomous Host Streams Command c, Command Ii dddd, Packet

Pressure Systems, Inc. 98RK-1 & 9816 User’s Manual©

DEFINE/CONTROL AUTONOMOUS HOST STREAMS (Command 'c')

Purpose: Defines and controls the autonomous delivery of any of up to three concurrent high-speed data streams to the host computer. Such data streams may be delivered “continuously” without bound (until a command explicitly stops them), or be delivered in a “limited” amount (until a pre-specified fixed number of data packets have been sent). Each packet delivered may be synchronized by a “hardware trigger” or each packet may be delivered periodically as controlled by an internal software clock. These concurrent host streams are an alternate method of acquiring/delivering data rather than using the Read High-Precision Data ('r') command or the Read High-Speed Data ('b') command.

Host data streams, once activated in a module, deliver a sequence of TCP/IP data packets autonomously to the host (i.e., without host sending any particular command to the module to request each packet). WARNING: If these data streams are defined to occur at high rates, then each data packet received by the host must be processed and disposed of in a timely manner.

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 command letter.

‘ii’ is a sub-commandindex (augment code) preceded by a space character.

‘dddd’ are one or more optional datum fields, each preceded by a space character, which are parameters that differ per augment code ii.

	NOTE: all parameters are separated by a space.
Response	Depends upon particular sub-command (ii) sent. See below.
Autonomous	Depends upon particular sub-command (ii) sent. See below.
Packet

Description: The firmware of a Model 9816 module, once fully initialized, continuously scans and converts data for all internal pressure channels at the highest possible speed. The result of such scanning is a continuously-updated EU data buffer, available to three concurrent host data delivery tasks, or available to other standard data acquisition commands of the module. Each host delivery task can grab engineering-unit data values from the EU data buffer and deliver them to the host in its own programmable data stream (a sequence of TCP/IP packets that autonomously arrive in the host, as long as the host has enough TCP/IP buffering space to hold them).

Special augments of this command (using the first parameter, ii) can configure each data stream with the particular channels whose data are delivered, the datum format, the delivery rate, and other characteristics. It can also start, stop, or un-define a single stream or all defined streams.

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