Chapter 8. Servicing the PT878

8.10.3 Testing the Watchdog Timer Circuit

The PT878 includes a watchdog timer circuit. If a software error causes the meter to stop responding, this circuit automatically resets the meter. A properly functioning PT878 restarts if you run the Watchdog Test.

To start the Watchdog Test, scroll to the Watchdog Test option in the Test Menu and press [ENTER]. The screen appears similar to Figure 126 below.

 

Site Program Meter Logging

 

Service

 

 

 

 

 

 

 

Dew Point, Watchdog°C

TestReportsSignal,

dB

 

 

 

** WARNING **

 

Test

 

 

 

X

 

 

 

 

 

 

Refer

TestnceScreen

 

 

 

 

 

Units

 

MIS

32

 

 

 

 

 

 

 

 

ProbeTestKeys

 

 

 

 

 

This test should automatically

 

 

 

 

 

 

 

 

 

-52.0

 

Factory Defaults

 

 

 

 

 

restart your meter!

 

 

 

Watchdog Test

 

 

 

 

 

Flash Update

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Factory Calibration

 

 

 

 

 

 

Press ‘Yes’ to start the test.

 

 

 

 

 

 

 

 

 

Pressure, PSIg

Run Time, Hours

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Press ‘No’ to cancel the test.

10.0

 

 

 

 

 

 

 

 

 

 

 

 

55.00

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

6

 

 

12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

No

Yes

Figure 126: Watchdog Test Screen

Press [F2] (No) to cancel the test and return to the Menu screen, or press [F3] (Yes) to start the test. The PT878 should go blank for a few seconds, and then restart. If it does not follow this sequence, consult the factory.

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Transport® Model PT878 Portable Liquid Flowmeter User’s Manual

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Page 206
Image 206
GE PT878 Testing the Watchdog Timer Circuit, This test should automatically, Factory Defaults Restart your meter
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PT878 specifications

The GE PT878 is a state-of-the-art portable ultrasonic flow meter designed for the precise measurement of liquid flow in various applications. As part of General Electric’s renowned instrumentation lineup, the PT878 combines innovative technology with user-friendly features, making it an invaluable tool for engineers, technicians, and plant operators.

One of the standout characteristics of the PT878 is its non-invasive measurement capability. The meter utilizes clamp-on transducer technology, allowing it to be installed on the exterior of the pipe, eliminating the need for invasive procedures which can disrupt the system or require pipe cutting. This non-contact approach not only simplifies installation but also enhances the device’s versatility, as it can be applied to a wide range of pipe sizes and materials.

The PT878 leverages advanced digital signal processing and sophisticated algorithms to provide accurate and reliable flow measurements. It operates using the time-of-flight method, whereby ultrasonic signals are sent and received through the fluid in the pipeline to determine the flow rate. This technology allows for remarkable precision, ensuring that operational efficiency can be maintained.

Moreover, the PT878 is equipped with features such as a bright, easy-to-read display, intuitive navigation, and robustness against harsh environmental conditions. Its compact and lightweight design enhances portability, making it suitable for field applications. The meter operates on battery power, providing a long-lasting solution for remote monitoring and temporary installations.

Another impressive aspect of the PT878 is its ability to measure not only water but also a variety of liquids, from hydrocarbons to chemicals. It supports multiple measurement modes, including volumetric flow and velocity, offering a level of flexibility that caters to diverse industrial needs.

In addition to flow measurement, the PT878 offers data logging capabilities, allowing users to store and analyze flow data over time. This function is vital for understanding trends, diagnosing issues, and optimizing system performance. Users can easily transfer data to computers for comprehensive analysis, enhancing operational insights.

With its combination of innovative technology, user-friendliness, and robust measurements, the GE PT878 ultrasonic flow meter stands out as a comprehensive solution for industries requiring reliable liquid flow measurement. Whether in a manufacturing plant, a water treatment facility, or any application requiring fluid monitoring, the PT878 delivers exceptional performance and accuracy.
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