# EFT Simulator Duration Time Setting / IEC 61000-4-4 / KeyTek CE 40

I've got an antique EFT simulator, it's a KeyTek CE-40. I'm debugging a device for EFT as per EN 61000-4-4. The manufacturer doesn't provide support for the device anymore and I don't have a product manual.

As per the standard, the burst duration should be 15 ms.

When I go to the device burst duration setting, I see some weird time symbol that is not in "ms" -- picture is attached.

Does anyone know what the time symbol they are showing there is? Is it a microsecond?

Anyone from the early 90s have any ideas?

• that may be 15 pulses – jsotola Jan 31 at 23:40
• @jsotola - I totally agree. This older device you can't change the waveform like later KeyTek devices, so it makes sense that you can just add or change the pulse parameters. I wish it said "pulse count" or something a bit more helpful. But this is how things go with old equipment with no manuals to be found. – Leroy105 Feb 3 at 21:02

Does anyone know what the time symbol they are showing there is?

I haven't used that equipment. However one guess is that 15 pls on the menu is 15 pulses (at the set period etc.).

To help to confirm/deny that guess, I would use a small voltage setting, configure an appropriate oscilloscope probing setup for that voltage, and I would view what simulated noise the device puts onto its output. Do you see 15 pulses?

Then see if changing that "pls" value on the menu does change the number of pulses - i.e. reverse-engineer the meaning of that menu setting, by fixing all values except that one, changing that one setting and observing the output.

• I don't have a voltage divider handy with the required connections, but I have to agree that is the pulses per time sequence. Thank you for your good sense. Later KeyTek devices let you modify the transient waveform. The standard calls for 75 pulses (with a duration of each pulse as 15ms) with a period of 300ms break in-between. The voltage setting is lowest at 200V, so theoretically I think my Rigol scope can handle that but I would rather not be running some unknown output into my scope! I may just send out the device for calibration, since it's definently EFT failing devices. – Leroy105 Feb 3 at 20:57

Looks like 15 PuLSes for 300 ms is 50 Hz rep rate.

Each pulse is likely as follows;

Pulse front time    1.2 us ± 30%
Pulse time to half value    50 us ± 20%
Current     Max. 2,500 A ± 10%
Pulse front time    8 us ± 20%
Pulse time to half value    20 us ± 20%
Polarity    Positive/negative/alternating