Question

We have several Endevco® model 4416B IEPE power supply units that are of unknown working condition. Can you provide instructions on the best means of performing a go-no-go test on these units?

Answer

For customers who may not already be familiar, the Endevco® model 4416B is a small, battery-operated, low-noise power supply and amplifier, designed for compatibility with Isotron® (IEPE-type) transducers. They are designed to supply power to the transducer from a constant current source with a selectable gain of 1 or 10. The conditioner is powered by rechargeable NiCad batteries, which offer eight hours of continuous use. Units are also fully operational during a typical battery recharging cycle. An LED status indicator notifies the user of short, open or normal operating conditions. In addition, the Endevco® model 4416B contains internal automatic power shutdown circuitry to protect the rechargeable batteries from deep discharge damage.

The following test procedure is a general guideline for performing a go-no-go test on the Endevco® model 4416B power supply/amplifier. It is important to note that this is a general and informal guideline, created to support urgent field requests, and is not a formally published instruction document. To successfully conduct a go-no-go test, the following steps are recommended:

Figure 1

Status LED test

1. Make sure the battery of the Endevco® model 4416B is fully charged.


2. Hook up the test setup, as shown in Figure 1.


3. Turn the signal generator output all the way down and do not turn power on.


4. Power up the 4416B and set the gain to 1. The status LED of 4416B should indicate green if the circuit in Figure 1 is properly connected.


5. Momentarily connect the Vin line to ground (short input to ground). The status LED should indicate RED. The LED will turn off if the input line to the 4416B is disconnected (simulating transducer is removed or input line is open).

Gain 1 test

1. Restore the hook up as shown in Figure 1.


2. Turn the signal generator output all the way down and turn power on.


3. Power up the 4416B and set the gain to 1. The status LED should indicate green.


4. Set the signal generator output to sine and set the frequency to 1 kHz. Raise the input voltage Vin to 1 Vac pk.


5. Monitor the output Vout with an oscilloscope, in anticipation of a clean sinusoidal waveform at 1 Vac pk at 1 kHz.

Maximum output swing test at Gain = 1

1. Set the signal generator output to sine and set the frequency to 1 kHz. Raise the input voltage Vin to 5 Vac pk.


2. Monitor the output Vout with an oscilloscope expecting a clean sinusoidal waveform at 5 Vac pk at 1 kHz.

Gain 10 test

1. Turn the signal generator output all the way down and turn power on.


2. Power up the 4416B and set the gain to 10. The status LED should indicate green.


3. Set the signal generator output to sine and set the frequency to 1 kHz. Raise the input voltage Vin to 0.1 Vac pk.


4. Monitor the output Vout with an oscilloscope expecting a clean sinusoidal waveform at 1 Vac pk at 1 kHz.

Maximum output swing test @ Gain =10

1. Set the signal generator output to sine and set the frequency to 1 kHz. Raise the input voltage Vin to 0.5 Vac pk.


2. Monitor the output Vout with an oscilloscope expecting a clean sinusoidal wave form at 5 Vac pk at 1 kHz.