The maintenance crew or process operator often require access to real time data residing in the process control system to help them diagnose operation problems or simply to track the process behavior while walking on the plant floor, the system gives realtime information on process variables actual values, machinery status, etc.
The system has a process variables database editor and maintenance tool to manage which PALM users have access to the plant information database (see database.jpg file) this application is written in VB 6.0 and creates and downloads a pdb file to the target user PDA when hotsync. This data can also be imported from the control system database so no data capture is required, the database contains key information like instrumentation physical connection point, engineering units, calibration range, etc. to quickly help diagnose and solve the operation problem. The attached data base is just a small fragment of total database.
This software module also handles the data acquisition requests sent by the wireless PALM devices network by accessing the real time data on the process control system via OPC (OLE for Process Control) (see server.jpg). The server software verifies the PALM RF link data integrity via CRC calculations, gets the data from the control system network, formats the information packets and send data back to the PDA via the 900 Mhz. ISM band RF link (http://www.datahunter.com/).
The system uses PALM processors as wireless process control system data access terminals using a tiny RF modem powered from the RS232 PDA serial port, so no external power is required, there is a number of remote antennas to ensure system area coverage, all the RF link protocol CRC error checking and packet formatting is handled by a shared library (SLExample.prc, I forgot to change the name!!)and NSBASIC provides the graphic interfase capabilities and database handling.
The system utilization resulted on the following benefits:
a) The AIRLINX concept is an integrated information support system for field force operations. It assists maintenance crew to reduce equipment failure diagnostic and maintenance time, increasing operational readiness, usage significantly reduced the typical plant shutdown problem diagnose time to less than 5 minutes.
b) Eliminates Process Control Operators distractions caused by maintenance crew information requests, focusing their attention to process control, operation and optimization.
c) Plant management instantaneous access to key operation and quality control process variables.
d) Integrates off the shelf, hardware and software components into an open architecture system, than can be interfaced to any Process Control System.