Automatic Self-Test In The Background; Selt-Test Called Externally By The User - holthausen elektronik ESW-small-Compact User Manual

Electronic Vibration monitoring Unit
ESW ® -small-Compact

17.1 Automatic self-test in the background

If an error occurs, the green LED flashes one to three times depending on the type of the
error, the pre and main contact trips and a fault current of 22mA can be measured at the
analog output. Items that are monitored include:

Operating voltage (Error code: LED flashes twice)

Temperature (Error code: LED flashes twice)

Threshold value potentiometers (must be changed in the set mode only)
(Error code: LED flashes once)

Sensor (Error code: LED flashes thrice)
If the cause of the error is remedied, the device goes back to its normal operation.

17.2 Selt-test called externally by the user

The test called by the user consists of 2 parts. The device cannot resume normal
measuring operation during the test.
The sensitivity of the analog part is checked first. For this purpose, in place of the
sensor signal a test signal is fed internally and the measured values are outputted at
the analog output. In the event of an error an alarm is outputted at the pre and main
contact. Subsequently, the on and release delay times for the pre and main contact
are outputted.

The self-test is activated by means of switch (S1) in the device (ON) and is visually
indicated by the flashing green LED. The entire test takes a few seconds.

Next, a current of exactly 4 mA must be measurable for 2 s at the analog output.

Later the sensor is disconnected internally and the following analog levels are
checked using a test signal. The values measured by the processor are outputted at
the analog output. If sensitivity is set to 10mm/s, a current of approx. 16 mA must be
outputted for 2 s. If sensitivity is set to 20mm/s, it should be possible to measure
approx. 8mA for 2 s followed by 16mA for another 2s at the analog output. If the
measuring range is set to 50mm/s, currents of 3.2mA followed by 6.4mA and 16mA
are expected at the analog output. If the deviation in the 16mA value is more than
20%, an alarm is outputted.

This is followed by the test for the delay and release periods for the relay. In this test,
a current of 22 mA is outputted at the analog output.

Afterwards the two delay periods of the relays expire, which is indicated by the
flashing of LEDs (yellow for threshold value 1, red for threshold value 2).

After the expiry of response delay 1 for threshold value 1, relay 1 responds and the
yellow diode lights for a time period equal to release delay 1. Then the relay releases
again and the LED goes out.
13
holthausen
elektronik GmbH