Customer Solutions

PacBell Increases Remote Monitoring Capabilities with FieldPoint Technology

Author(s):

Tim Dense, Cal-Bay Systems, Inc

Industry:

Telecommunications

Product:

Compact FieldPoint, Distributed I/O, FieldPoint, LabVIEW, LabVIEW Real-Time

The Challenge:

Replacing and significantly updating an existing analyzer that monitors the status of telecom transmission signals.

The Solution:

Using National Instruments new FP-2015 and LabVIEW to replace PacBell’s traditional analyzer used to monitor telecom transmission signals with a more efficient stand-alone data acquisition instrument capable of monitoring remote microwave transmission statements for up to six months.

Upgrading an Outdated Analyzer
PacBell, a wholly owned subsidiary of SBC Communications, provides telecommunications services worldwide. Using microwave transmission towers, PacBell transmits voice and data information over the airwaves. Fine tuning the amplification of the microwave signal is important to ensure the quality of the transmission through changing environmental conditions, and it is imperative to acquire data to accurately determine where a failure occurred.

Since the mid-1980s, PacBell has used an Oi Electric Fade Analyzer to monitor voltage signals from the amplifiers of microwave transmission towers (up to 14 signals per station). The analyzer converts voltage signals to a microwave decibel scale and logs them for retrieval at a later date. For this conversion, the system uses a linear interpolation between calibrated data points, which an operator enters as a look-up table (LUT). Each signal has a different calibration curve, so the operator must enter an LUT for each transmission point the system is monitoring. Typically, the analyzer is left unattended in the field for up to two weeks. After monitoring, the operator returns the analyzer to the office to retrieve the data.

PacBell was ready to take advantage of the advances in technology during the last 15 years, so they contracted Cal-Bay Systems, Inc., a National Instruments Select Integrator, to develop a user-friendly instrument to duplicate the capabilities of the existing Fade Analyzer while adding several new features. The modifications included longer monitoring capability between downloads, local and remote communications, simplified data retrieval, enhanced LUT downloading, and the addition of environmental monitoring (temperature and humidity). The usability improvements included upgrading the existing 10-key LED user interface to a remote-control, menu-driven terminal program.

Creating a Smaller, More Powerful System
The instrument developed by Cal-Bay consists of the new FP-2015 module controller, two FP-AI-110 modules, a 33.6 Kbps modem and a 24V power supply. All these components are fully integrated into a stand-alone, compact NEMA-4 rated steel enclosure. Fourteen BNC connections on the front panel of the instrument (using BNC panelettes from National Instruments) provide a quick-connect interface for voltage gain signals. One four-wire, twistlock connection provides an interface for the two environmental sensors. Connections for power, communications, and environmental sensors are all in compliance with industry standards and fully removable for packaging and shipping.

A major goal of this project was to avoid the large footprint of a typical PC-based data acquisition system. We achieved this by using the FP-2015 controller. Using NI LabVIEW Real-Time as the development platform, we leveraged the FP-2015 module as an embedded system capable of operating remotely for long periods of time rather than a stand-alone controller. Because the FP-2015 uses LabVIEW Real-Time software, the system now can handle large data sets and remote data transfer via modem and serial port.
The long-term monitoring requirements of the PacBell application demanded the 512 MB of nonvolatile storage provided by the FP-2015. Cal-Bay Systems multiplexed the FP-2015 onboard serial port to interface with an industry-standard 56Kbps modem in addition to a local serial port. The system was unable to use both protocols at the same time, so we designed a port redirector into the instrument. With the flip of a switch, the operator now can alternate between local and remote modes to upload the LUT data directly from a laptop or download acquired data from a remote field location.

We chose NI LabVIEW Real-Time for this application because it provides stand-alone operation of the FP-2015 module. As a result, it collects and averages data over a period of one minute, and stores it in a circular database of 100,000 records. Once the database is full, the system overwrites old data with new data.
Cal-Bay developed a protocol based on the industry-standard Xmodem protocol. This facilitates the downloading of data and the uploading of LUT data via HyperTerminal (specifically requested by PacBell).

Meeting and Exceeding Expectations
We started the development of this project with the goal of replacing an outdated analyzer with a sophisticated, compact solution using NI products. By leveraging the capabilities of the new FP-2015 and the flexibility of LabVIEW Real-Time, we developed a data-logging instrument that is easy to use, compact, and capable of long-term operation in remote locations. The LabVIEW Real-Time/FieldPoint 2015 combination is a real asset to embedded systems developers.

For more information, contact:

Tim Dense

Cal-Bay Systems, Inc.

3070 Kerner Blvd., Suite B,

San Rafael, CA 94901

Tel: (415) 258-9400

Fax: (415) 258-9288

E-mail: info@calbay.com

tim_dense_pc_2002_communications.pdf

View the entire user solution in Adobe Acrobat PDF format.