Remote acquisition: processing and generation of digital signals for a reversible counter through LabView environment.
Rancea, Irina ; Sgarciu, Valentin ; Stamatescu, Grigore 等
1. INTRODUCTION
Technological process supervision involves acquisition and
monitoring of a large number of parameters. Using and Internet
connection one can store these parameters in high performance data bases
for future processing. This paper is focusing on a solution for
acquisition, processing and generation of digital signals using
reversible counters, designed for long distances.
2. SYSTEM ARCHITECTURE
2.1 Hardware Resources
The system uses a plug-in board for acquisition/generation of
analogical and digital signals, KPCI-3102 provided by Keithley. Its
schema (Fig. 1) contains:
* 16 Channel MUX--16 analogical inputs connected to the Gain Amp
(amplifier with programmable scale).
* ADC--analogical-digital convertor with controlling the frequency
of the conversion clock.
* Tri-state buffers--tri-state memories that allow selection of the
analogical channels or their equivalent as digital inputs on two ports
of 8 bits.
* Sample input FIFO--FIFO of 1k per each input sampling.
* Bidirectional 8-bit Latch--bidirectional programmable memories
for the digital inputs/outputs, ports A and B.
* Multiplying DAC--digital-analogical convertors.
* Trigger Clock Logic; A/D counter 24-bitsl TScan counter
24-bits--digital circuits for extern synchronization of the analogical
channels.
* CGL, Channel Parameter--registers.
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2.2 Application Architecture
The acquisition/generation system is installed and configured on a
local workspace; the access to the application server is done through an
Internet connection as in Fig.2, Fig.3 and Fig.4. (Shirer, 2001) (Ahmad,
2003) The application has a communication module that is responsible
with the remote data transmission. It was developed using NI DataSocket
Server-Client communication. (Vlad et. al., 2005)
3. CASE STUDY
3.1 Acquisition of digital signals from a reversible counter
For the acquisition of digital signals two test cases have been
taken into consideration--direct counting and reverse counting. The
assembly schema is shown in Fig. 5, where:
* GS--TTL rectangular signal generator.
* PCL--board with logical circuits where the counter, the decoder
for seven segments and the display with seven segments are mounted.
* SA--power supply 5 V and 1A.
* K--mono-polar switch for applying the TTL input to DC (direct
counting) and RC (reverse counting).
* STP-68--board for extern connections, bind through 1:1 CAB-305
cable to the KPCI-3102 connector.
* Sample input FIFO--FIFO of 1k per each input sampling.
* Bidirectional 8-bit Latch--bidirectional programmable memories
for the digital inputs/outputs, ports A and B.
The application's front panels are shown in Fig.6 and Fig.7.
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3.2 Processing and generation of digital signals for a numerical
display
The application consists in a structure of binary counter on four
ranks, a decoder for seven segments and a display on seven segments that
will command the seven segments display SN7545. The assembly schema is
shown in Fig. 8, where:
* PCL--board with logical circuits where the counter, the decoder
for seven segments and the display with seven segments are mounted.
* SA--power supply 5V and 1A.
* STP-68--board for extern connections, bind through 1:1 CAB-305
cable to the KPCI-3102 connector.
[FIGURE 8 OMITTED]
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The application front panel is shown in Fig. 9.
The application block diagram for generating digital commands on
B(1) port is shown in Fig. 10.
The both case studies presented are using the multifunctional board
of analogical and digital inputs-outputs KPCI-3102 provided by Keithley
compatible with the PC bus.
4. CONCLUSION
The applications were designed and developed to test the
possibility of adding remote monitoring. It was used for a series of
experiments between several laboratories. From one point of view one can
process the experimental data gathered from a real process, but can also
see the result of one remote command sent to industrial equipment in the
real time. The main part is, as we mentioned at the beginning, the
server with the KPCI-3102 board provided by Keithley. The server is able
to manipulate multiple applications in the same time.
5. REFERENCES
Adao, A.S. (2004). Highly Digital, Low-Cost Design of Statistic
Signal Acquisition in SoCs, Proceedings of Design Automation and Test in
Europe, Vol. 3, ISBN 0-7695-20855-3
Ahmad, M.R.; Khan, N.; Hooong, C.C.; Abas, N. (2003). Remote data
acquisition through Internet based telemetry, Research and Development.
2003. Scored 2003. Proceedings Student Conference, pp. 237-244, ISBN
07803-8173-4, August 2003
Thomson, E.A.; Acierto, J.; Chavis, A. (2003). Integration of data
acquisition hardware into an undergraduate digital signal processing course via the capstone senior design project, Frontiers in Education,
Vol. 2, November 2003, DOI 10.1109/FIE.2003.126493
Shirer, D. (2001). Labview 6i Adds Internet Features to Data
Acquisition Environment. Computing in Science and Engineering, Vol. 3,
No. 4, (July/August 2001), pp. 8-11, ISSN 152109615
Vlad, M.; Sgarciu, V.; Rancea, I. (2005). Acquisition and
monitoring of process parameters using Internet, CSCS15 15th
International Conference on Control Systems and Computer Science,
Politehnica University Bucharest, Vol. 1, pp. 8-14
