Pressure Systems 98RK-1 Functional Command Overview, Interpreting Engineering Units Output

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

user to make reasonableness checks on them. The Read Internal Coefficients ('u') command will return them on demand.

3.1.4.3Interpreting Engineering Units Output

All Model 9816 modules perform all internal pressure calculations in engineering units (EU) of pounds per square inch (psi). By default, all pressure data in responses and command parameters will also be in psi. A different engineering unit (e.g., kPa) may be obtained by changing an internal EU Pressure Conversion Scaler (normally 1.0). See the “Read/Download Internal Coefficients” ('u'/'v') commands (array 11, coefficient 01).

3.1.5Functional Command Overview

The various NetScanner™ System commands for 9816 modules are best introduced by classifying them into functional groups and then describing how each function is carried out in a typical system. The following functions are defined for this purpose:

●Start-up Initialization

●Scan List Definition for Acquisition

●Calibration Adjustment of Engineering Unit Correction Coefficients

●Acquisition/Delivery of Data to Host

●Network Query and Control

Please look ahead to Table 3.1, labeled 9816 NetScanner™ System Commands, in Section 3.2, for a quick-look summary of all commands available to the Model 9816 module. Each command may be referenced by both its functional title and by its command id in the functional discussion sub-sections below.

The Detailed Command Description Reference immediately follows the table in Section 3.2, with each command description occupying a page (or more if necessary). Command descriptions in this section (as in the table) are ordered first by type (TCP/IP then UDP/IP), then by “command id” in ASCII order (UPPERCASE letters (A .. Z) first, then lowercase letters (a .. z)).

3.1.5.1Start-up Initialization

Since power supplies may be distributed widely across a network of modules and host computer(s), it is not uncommon for modules (singly or together) and the host to lose power independently. Thus, their power may be restored at different times. Start-up initialization for every module must normally be performed when its power is restored, as each module enters default states after power-up, which may not be the state the host computer had previously been operating in. Any previous TCP/IP socket connection is also lost after power failure and must be re-established between host and module before any TCP/IP commands can be recognized by the module. These commands are generally used to detect that start-up initialization has occurred (or to force reset at other times), after which other commands may be used to restore the original operating condition.

In the NetScanner™ System (using the 98RK-1 Scanner Interface Rack), the Power-Up Clear ('A') command may be used as a simple command to elicit a known response from a module. Although this causes no internal function within the module, it will result in an acknowledgment being returned to the host computer to verify proper communications. The best way to detect

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