Empathy List Archives

RE

Randy Evans

Fri, Feb 3, 2012 4:58 PM

I am planning on building an equivalent Fluke 731B transfer Standard using a VRE310 10V Precision reference and LTC5400 Quad resistor as a precision 10:1 divider, plus ancillary circuits. However, before starting the detailed design I modeled the Fluke 731B circuit in LTSpice. The 1V, 1.018V and 1.019V outputs are fine but the 0 to 999uV delta E adjustment circuit for the delta V, 1.018 + delta E and 1.019 + delta E outputs does not work per the circuit modeled from the schematic. I have double and triple checked my LTSpice schematic per the Fluke 731B schematic but I can't see any difference. Maybe I am just too close to the forest to see the trees.

Note: The Fluke 731B schematic from the manula I have does not show the value of the delta E adjustment pot but the parts list shows a value of 5K ohms.

Does anyone have any ideas? I can forward the LTSpice schematic I am using to anyone that might be interested, just send me your e-mail address.

Thanks,

Randy Evans

I am planning on building an equivalent Fluke 731B transfer Standard using a VRE310 10V Precision reference and LTC5400 Quad resistor as a precision 10:1 divider, plus ancillary circuits. However, before starting the detailed design I modeled the Fluke 731B circuit in LTSpice. The 1V, 1.018V and 1.019V outputs are fine but the 0 to 999uV delta E adjustment circuit for the delta V, 1.018 + delta E and 1.019 + delta E outputs does not work per the circuit modeled from the schematic. I have double and triple checked my LTSpice schematic per the Fluke 731B schematic but I can't see any difference. Maybe I am just too close to the forest to see the trees. Note: The Fluke 731B schematic from the manula I have does not show the value of the delta E adjustment pot but the parts list shows a value of 5K ohms. Does anyone have any ideas? I can forward the LTSpice schematic I am using to anyone that might be interested, just send me your e-mail address. Thanks, Randy Evans

RK

Rob Klein

Fri, Feb 3, 2012 5:55 PM

Hi Randy,
Send me the LTSpice file and I'll take a look at it for you.
Regards,
Rob Klein.
Op 3-2-2012 17:58, Randy Evans schreef:

I am planning on building an equivalent Fluke 731B transfer Standard using a VRE
310 10V Precision reference and LTC5400 Quad resistor as a precision 10:1 divide
r, plus ancillary circuits. However, before starting the detailed design I mode
led the Fluke 731B circuit in LTSpice. The 1V, 1.018V and 1.019V outputs are fi
ne but the 0 to 999uV delta E adjustment circuit for the delta V, 1.018 + delta
E and 1.019 + delta E outputs does not work per the circuit modeled from the sch
ematic. I have double and triple checked my LTSpice schematic per the Fluke 731
B schematic but I can't see any difference. Maybe I am just too close to the fo
rest to see the trees.

Note: The Fluke 731B schematic from the manula I have does not show the value of
the delta E adjustment pot but the parts list shows a value of 5K ohms.

Does anyone have any ideas? I can forward the LTSpice schematic I am using to a
nyone that might be interested, just send me your e-mail address.

Thanks,

Randy Evans

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References

Hi Randy, Send me the LTSpice file and I'll take a look at it for you. Regards, Rob Klein. Op 3-2-2012 17:58, Randy Evans schreef: I am planning on building an equivalent Fluke 731B transfer Standard using a VRE 310 10V Precision reference and LTC5400 Quad resistor as a precision 10:1 divide r, plus ancillary circuits. However, before starting the detailed design I mode led the Fluke 731B circuit in LTSpice. The 1V, 1.018V and 1.019V outputs are fi ne but the 0 to 999uV delta E adjustment circuit for the delta V, 1.018 + delta E and 1.019 + delta E outputs does not work per the circuit modeled from the sch ematic. I have double and triple checked my LTSpice schematic per the Fluke 731 B schematic but I can't see any difference. Maybe I am just too close to the fo rest to see the trees. Note: The Fluke 731B schematic from the manula I have does not show the value of the delta E adjustment pot but the parts list shows a value of 5K ohms. Does anyone have any ideas? I can forward the LTSpice schematic I am using to a nyone that might be interested, just send me your e-mail address. Thanks, Randy Evans _______________________________________________ volt-nuts mailing list -- [1]volt-nuts@febo.com To unsubscribe, go to [2]https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. References 1. mailto:volt-nuts@febo.com 2. https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts

AJ

Andreas Jahn

Fri, Feb 3, 2012 10:25 PM

Hello Randy,

is your VRE310 a "new" part (branded APEX) or is it a old "Thaler"
reference?

Some months ago I bougth 2 VRE3050A but the measured noise is well above the
typical value in the data sheet.
So if you have a APEX part it would be interesting for me wether the VRE310
is more quiet in low frequency noise (0.1 .. 10Hz).
For a 10V part it should be about 6uVpp typical.

Do you plan to heat the reference? Or how do you intend to get near to the
731B specs?

With best regards

Andreas Jahn

----- Original Message -----
From: "Randy Evans" randallgrayevans@yahoo.com
To: volt-nuts@febo.com
Sent: Friday, February 03, 2012 5:58 PM
Subject: [volt-nuts] Fluke 731B replacement

I am planning on building an equivalent Fluke 731B transfer Standard using a
VRE310 10V Precision reference and LTC5400 Quad resistor as a precision 10:1
divider, plus ancillary circuits. However, before starting the detailed
design I modeled the Fluke 731B circuit in LTSpice. The 1V, 1.018V and
1.019V outputs are fine but the 0 to 999uV delta E adjustment circuit for
the delta V, 1.018 + delta E and 1.019 + delta E outputs does not work per
the circuit modeled from the schematic. I have double and triple checked my
LTSpice schematic per the Fluke 731B schematic but I can't see any
difference. Maybe I am just too close to the forest to see the trees.

Note: The Fluke 731B schematic from the manula I have does not show the
value of the delta E adjustment pot but the parts list shows a value of 5K
ohms.

Does anyone have any ideas? I can forward the LTSpice schematic I am using
to anyone that might be interested, just send me your e-mail address.

Thanks,

Randy Evans

volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.

Hello Randy, is your VRE310 a "new" part (branded APEX) or is it a old "Thaler" reference? Some months ago I bougth 2 VRE3050A but the measured noise is well above the typical value in the data sheet. So if you have a APEX part it would be interesting for me wether the VRE310 is more quiet in low frequency noise (0.1 .. 10Hz). For a 10V part it should be about 6uVpp typical. Do you plan to heat the reference? Or how do you intend to get near to the 731B specs? With best regards Andreas Jahn ----- Original Message ----- From: "Randy Evans" <randallgrayevans@yahoo.com> To: <volt-nuts@febo.com> Sent: Friday, February 03, 2012 5:58 PM Subject: [volt-nuts] Fluke 731B replacement I am planning on building an equivalent Fluke 731B transfer Standard using a VRE310 10V Precision reference and LTC5400 Quad resistor as a precision 10:1 divider, plus ancillary circuits. However, before starting the detailed design I modeled the Fluke 731B circuit in LTSpice. The 1V, 1.018V and 1.019V outputs are fine but the 0 to 999uV delta E adjustment circuit for the delta V, 1.018 + delta E and 1.019 + delta E outputs does not work per the circuit modeled from the schematic. I have double and triple checked my LTSpice schematic per the Fluke 731B schematic but I can't see any difference. Maybe I am just too close to the forest to see the trees. Note: The Fluke 731B schematic from the manula I have does not show the value of the delta E adjustment pot but the parts list shows a value of 5K ohms. Does anyone have any ideas? I can forward the LTSpice schematic I am using to anyone that might be interested, just send me your e-mail address. Thanks, Randy Evans _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.

R

Randy

Sat, Feb 4, 2012 3:17 AM

It is the "Thaler" unit. I got it from a cancelled project. Do you have an easy test to check the noise level? The Linear Tech app note by Jim Williams is too expensive for me ($400 input cap).

Randy

Sent from my iPhone

On Feb 3, 2012, at 2:25 PM, "Andreas Jahn" Andreas_-_Jahn@t-online.de wrote:

Hello Randy,

is your VRE310 a "new" part (branded APEX) or is it a old "Thaler" reference?

Some months ago I bougth 2 VRE3050A but the measured noise is well above the typical value in the data sheet.
So if you have a APEX part it would be interesting for me wether the VRE310 is more quiet in low frequency noise (0.1 .. 10Hz).
For a 10V part it should be about 6uVpp typical.

Do you plan to heat the reference? Or how do you intend to get near to the 731B specs?

With best regards

Andreas Jahn

----- Original Message ----- From: "Randy Evans" randallgrayevans@yahoo.com
To: volt-nuts@febo.com
Sent: Friday, February 03, 2012 5:58 PM
Subject: [volt-nuts] Fluke 731B replacement

I am planning on building an equivalent Fluke 731B transfer Standard using a VRE310 10V Precision reference and LTC5400 Quad resistor as a precision 10:1 divider, plus ancillary circuits. However, before starting the detailed design I modeled the Fluke 731B circuit in LTSpice. The 1V, 1.018V and 1.019V outputs are fine but the 0 to 999uV delta E adjustment circuit for the delta V, 1.018 + delta E and 1.019 + delta E outputs does not work per the circuit modeled from the schematic. I have double and triple checked my LTSpice schematic per the Fluke 731B schematic but I can't see any difference. Maybe I am just too close to the forest to see the trees.

Note: The Fluke 731B schematic from the manula I have does not show the value of the delta E adjustment pot but the parts list shows a value of 5K ohms.

Does anyone have any ideas? I can forward the LTSpice schematic I am using to anyone that might be interested, just send me your e-mail address.

Thanks,

Randy Evans

volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.

It is the "Thaler" unit. I got it from a cancelled project. Do you have an easy test to check the noise level? The Linear Tech app note by Jim Williams is too expensive for me ($400 input cap). Randy Sent from my iPhone On Feb 3, 2012, at 2:25 PM, "Andreas Jahn" <Andreas_-_Jahn@t-online.de> wrote: > Hello Randy, > > is your VRE310 a "new" part (branded APEX) or is it a old "Thaler" reference? > > Some months ago I bougth 2 VRE3050A but the measured noise is well above the typical value in the data sheet. > So if you have a APEX part it would be interesting for me wether the VRE310 is more quiet in low frequency noise (0.1 .. 10Hz). > For a 10V part it should be about 6uVpp typical. > > Do you plan to heat the reference? Or how do you intend to get near to the 731B specs? > > With best regards > > Andreas Jahn > > ----- Original Message ----- From: "Randy Evans" <randallgrayevans@yahoo.com> > To: <volt-nuts@febo.com> > Sent: Friday, February 03, 2012 5:58 PM > Subject: [volt-nuts] Fluke 731B replacement > > > I am planning on building an equivalent Fluke 731B transfer Standard using a VRE310 10V Precision reference and LTC5400 Quad resistor as a precision 10:1 divider, plus ancillary circuits. However, before starting the detailed design I modeled the Fluke 731B circuit in LTSpice. The 1V, 1.018V and 1.019V outputs are fine but the 0 to 999uV delta E adjustment circuit for the delta V, 1.018 + delta E and 1.019 + delta E outputs does not work per the circuit modeled from the schematic. I have double and triple checked my LTSpice schematic per the Fluke 731B schematic but I can't see any difference. Maybe I am just too close to the forest to see the trees. > > Note: The Fluke 731B schematic from the manula I have does not show the value of the delta E adjustment pot but the parts list shows a value of 5K ohms. > > Does anyone have any ideas? I can forward the LTSpice schematic I am using to anyone that might be interested, just send me your e-mail address. > > Thanks, > > Randy Evans > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there.

RK

Rob Klein

Mon, Feb 6, 2012 12:46 PM

Randy,
I looked at those LT5400 parts and they look very promising. However,
unless you are planning on a negative 1V output, I don't quite
see how you are going to make a precision 10:1 divider with them.

Rob.
Op 3-2-2012 17:58, Randy Evans schreef:

I am planning on building an equivalent Fluke 731B transfer Standard using a VRE
310 10V Precision reference and LTC5400 Quad resistor as a precision 10:1 divide
r, plus ancillary circuits.

Randy, I looked at those LT5400 parts and they look very promising. However, unless you are planning on a negative 1V output, I don't quite see how you are going to make a precision 10:1 divider with them. - Rob. Op 3-2-2012 17:58, Randy Evans schreef: I am planning on building an equivalent Fluke 731B transfer Standard using a VRE 310 10V Precision reference and LTC5400 Quad resistor as a precision 10:1 divide r, plus ancillary circuits.

volt-nuts@lists.febo.com

Fluke 731B replacement