Somebody knows the RFL/Clarke HESS 828 Calibrator?

[max]

Hi,

is it normal that in a 828 RFL/Clarke HEss calibrator if i set
140mV(as example) at the output i have a tension that is instable :
140.20 to 139.80 all time? What can be?

In the range of 10 volt and 100 Volt the things are better?

Thanks

 

[john jardine]

"max" <ciulandro@yahoo.com> wrote in message
news:1178378120.419086.228310@y80g2000hsf.googlegroups.com...

Hi,

is it normal that in a 828 RFL/Clarke HEss calibrator if i set
140mV(as example) at the output i have a tension that is instable :
140.20 to 139.80 all time? What can be?

In the range of 10 volt and 100 Volt the things are better?

Thanks

Marvellous bit of kit!.

Over a 1 minute period I saw 139.88mV to 140.19mV. This ties in with what
you see. Even by itself, +/- 0.1% is not bad for the 3.5 digit setting
thumbwheels.
But ... the noise is not from the RFL but due to low level AC and RF pickup
on the leads from the RFL to the DVM.
A filter of say 1kohm and 1000uF across the DVM input and (my) display is
rock solid at 140.02mV for minutes on end.

Got a 828 manual you could share?.







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[maxi]

Hi,

Yes i've manual that i've download from the site of Clarke Hess.If you want
i can email to you.
The problem is that if i set 100 mV,all time my DMM read a instable value
that oscillate continuosly from 100 to 99.5 to 101 to 99.3 etc.
In the other range the last digits are more stable.
I've tried to put the filter acrossss the input of dmm but nothing the value
is always oscillating,in a second it's change 3,4,5 times!!!!
"john jardine" <john@jjdesigns.fsnet.co.uk> ha scritto nel messaggio
news:463cc3ff$0$2297$88260bb3@free.teranews.com...

"max" <ciulandro@yahoo.com> wrote in message
news:1178378120.419086.228310@y80g2000hsf.googlegroups.com...
Hi,

is it normal that in a 828 RFL/Clarke HEss calibrator if i set
140mV(as example) at the output i have a tension that is instable :
140.20 to 139.80 all time? What can be?

In the range of 10 volt and 100 Volt the things are better?

Thanks


Marvellous bit of kit!.

Over a 1 minute period I saw 139.88mV to 140.19mV. This ties in with what
you see. Even by itself, +/- 0.1% is not bad for the 3.5 digit setting
thumbwheels.
But ... the noise is not from the RFL but due to low level AC and RF
pickup
on the leads from the RFL to the DVM.
A filter of say 1kohm and 1000uF across the DVM input and (my) display is
rock solid at 140.02mV for minutes on end.

Got a 828 manual you could share?.







--
Posted via a free Usenet account from http://www.teranews.com

 

[john jardine]

"maxi" <maxitubo@virgilio.it> wrote in message
news:qfo%h.26547$R_5.855456@twister1.libero.it...

Hi,

Yes i've manual that i've download from the site of Clarke Hess.If you
want
i can email to you.
The problem is that if i set 100 mV,all time my DMM read a instable value
that oscillate continuosly from 100 to 99.5 to 101 to 99.3 etc.
In the other range the last digits are more stable.
I've tried to put the filter acrossss the input of dmm but nothing the
value
is always oscillating,in a second it's change 3,4,5 times!!!!

Yes. I'd be very pleased if you could email it!. My address is ...
john.jardine [@ sign] idnet.co.uk

Sounds like the voltage 828 control loop itself is a bit unstable. Maybe a
capacitor failing.
My unit has some internal noise that is coming in from the 240Vac power
inlet (LO-GND connecting link 'on' or 'off' it's still the same) but not
the amount you are noticing.

PS: Just confirming my filter was wired as this ...

.---------. .---------.
| CLARKE | | DMM |
| HESS | | |
| | | |
| | ___ | |
| POS o-----|___|--o----o POS |
| | 1k | | |
| | ---+ | |
| | --- | |
| | 1000u| | |
| NEG o------------o----o NEG |
'---------' '---------'



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