Randy:
Sorry my fault. You have to use the "RMATH" command to get the various
values stored in the registers. See the "RMATH" command in the User's Guide
for a list of what registers you can read.
I sure haven't found any other guides other than the 4 manuals. User's
Guide, Quick Reference Guide, Calibration Manual, and Assembly Level Repair.
It is just a matter of reading the guides and trying to remember what
commands are available. It took me a lot of time to figure out what
commands I use now. I am sure I am missing other commands that might be
useful.
Bill
----- Original Message -----
From: "Randy Evans" <randyevans2...@gmail.com>
To: "Discussion of precise voltage measurement" <volt-nuts@febo.com>
Sent: Sunday, August 24, 2014 6:04 PM
Subject: Re: [volt-nuts] 732A and Prologix received
> Bill,
>
> I am trying to figure out the MATH function without much success. I input
> the sequence you said (I looked up the instructions to understand what you
> did - seems logical), BLUE DEFKEY BLUE F1 MATH 14;NRDGS 40;TRIG 4;TRIG;
and
> it shows up on the display when I input BLUE F1. I hit ENTER and it takes
> the 40 measurements and the MATH symbol shows on the display during the
> measurements. After the SMPL symbol no longer blinks I hit MATH 2 and I
> get a MATH ERR symbol on the display. I tried it a couple of times and
the
> same result so I am doing something wrong. Is there a better source for
> explaining how to do front panel masurements than the User Guide, which
> seems oriented at programming automatic rather than manual measurements.
>
> Randy
>
>
>
> On Sun, Aug 24, 2014 at 4:46 PM, Bill Gold <wpgold3...@att.net> wrote:
>
> > Randy:
> >
> > The MATH function is accessible from the keypad. I don't have an
IEEE
> > interface right now that works. You can also program the numeric keypad
> > keys to have preprogrammed functions. DEFKEY
> >
> > I have made my own "low thermal" measurement leads from Pomona #4892
> > banana plugs and Belden #9272 wire. Why 9272, because it was handy at
the
> > time. It is tin plated copper, shielded twisted pair 20 ga. I have
plans
> > to do custom cables with 16 ga. bare copper wire that I will twist and
then
> > put a braided shield over it. I simply cannot find what I want so I
will
> > build my own cable. I have done something like this before and it
worked
> > fine. When I get a "round toit".
> >
> > I have 6 ea. Pomona 1756-48 spade lug low thermal leads that I have
> > used
> > in the past to verify my homemade "low thermal" leads as described
above.
> > Frankly I cannot see any difference between using the 1756 cables and my
> > homemade cables once I give them a few minutes for the thermals to go
away.
> > As far as I can tell and measure the differences, if any, are below 0.1
ppm
> > at 10 volts.
> >
> > Since the 10 volt, 1.0 volt and 1.018 volt outputs on the 732A are
all
> > adjustable you may be seeing a misadjusted 1 volt from the 732A. As far
as
> > the instability of the readings it is hard to determine which is causing
> > the
> > problem. I have programed (DEFKEY) a numeric keypad key #1 with the
> > following code. "MATH 14;NRDGS 40;TRIG 4;TRIG ;" So what this does is
> > set
> > the MATH to "Statistics" (store high reading/low reading/ and mean of
the
> > readings) in the registers, the number of readings to "40", the trigger
to
> > "hold" (which keeps the meter from triggering until I press "ENTER" and
> > then
> > trigger the sequence of 40 readings when I push the "ENTER" button. You
> > can
> > do all of this manually from the keypads but since I use this sequence a
> > lot
> > I have preprogrammed it. This is after I set digits to "8" and PLC to
100.
> > Once those 40 readings are finished then you can access the various MATH
> > statistic registers, using the menu, by entering "MATH" and then a 2 for
> > low, a 4 for mean, and 13 for high. Of course you could do all of this
> > through the IEEE also. The 3458A has a very rich set of measurement
> > commands. I am still learning all of them. It depends upon what I am
> > trying to accomplish.
> >
> > Since the 1.018 and 1.0 volt outputs are passive and derived from
> > resistive dividers from the 10 volt, I don't see how they could
contribute
> > to the varying readings you are measuring. I think I would put a short
on
> > the input of the 3458A and manually set the range to 1 volt and then
> > observe
> > the variations that way without the 732A involved. When I do this I see
a
> > variation from low reading to high reading of 0.125 uVolts and then
another
> > 40 I get 0.155 uVolts. This is without the GUARD connected to the low
side
> > of the measurment terminals, GUARD connected doesn't seem to affect the
> > readings. So that is the base noise of the 3458A without the 732A,
> > somewhere below .2uVolts. When hooked up to the 732A 1.0 volt output I
got
> > a variation of 0.159 uVolts using the same 40 reading method above. I
> > would
> > use this to determine where your problem might exist. Just having the
> > meter
> > input shorted will point you in the right direction. Meter, cables or
> > 732A.
> >
> > Sorry for the long dissertation. Friends get mad at me for being so
> > detailed sometimes.
> >
> > Bill
> >
> > ----- Original Message -----
> > From: "Randy Evans" <randyevans2...@gmail.com>
> > To: "Discussion of precise voltage measurement" <volt-nuts@febo.com>
> > Sent: Sunday, August 24, 2014 7:22 AM
> > Subject: Re: [volt-nuts] 732A and Prologix received
> >
> >
> > > Bill,
> > >
> > > I have convinced myself that the problem I an seeing is due to
thermals.
> > > If I move the cables (with gold-plated banana plugs) using a small
towel
> > > rather than letting my hand touch the plugs, it is much more stable.
If
> > I
> > > then hold the banana plug with my hand after the reading has
stabilized,
> > > the reading drifts rapidly upward. I am trying to check the stability
of
> > > the reading but I haven't figured out the MATH function yet. I assume
> > this
> > > is a programmed function using GPIB only?
> > >
> > > The stability I am seeing by manually recording readings (using NLPC
of
> > 100
> > > and 1000) is much greater than what you are measuring on your system.
> > Not
> > > sure how to ascertain if it's the 3458A or the 732. The value of the
> > > readings are very different between the two - the 3458 reads about 50
uV
> > > high on the 10 V output and about 12 uV low on the 1V output. Rather
> > large
> > > differences (this is after an ACAL). I need to find some better
cables
> > to
> > > make sure the errors are not due to thermals again.
> > >
> > > Randy
> > >
> > >
> > > On Sat, Aug 23, 2014 at 10:21 AM, Bill Gold <wpgold3...@att.net>
wrote:
> > >
> > > > Randy:
> > > >
> > > > I get 6 volt 4 amp/hr (or 4.5 amp/hr) batteries and they will
fit
> > > > perfect. Power Sonic PS-640, Genesis NP4-6, Panasonic LC-R064R5C
and
> > > > others
> > > > that are in this size and package. Order from one of the usual
> > electronics
> > > > distributors like Allied, Mouser, Digikey. This is a very common
> > battery
> > > > as
> > > > it is used in a lot of "EXIT" signs so they are lighted when the
power
> > goes
> > > > out. I don't see how the 12V 7AH will fit as they are too large. I
> > guess
> > > > you could use a 12V 5AH (PS1250) as it is the same size as 2 x 6
volt 4
> > AH
> > > > but the terminals are in the wrong place so you will have to
"nibble"
> > out
> > > > the aluminum plate that holds them in the 732A battery pack. You
have
> > to
> > > > be
> > > > careful if you use the 12v 5AH as you will have 4 extra battery
> > connection
> > > > leads to deal with and connect correctly. I would stick with the 6V
> > 4AH.
> > > > New batteries will last around 12 to 14 hours before the "CAL" light
> > goes
> > > > out when AC power is not applied. So shipping to Cal Lab can be a
> > problem
> > > > if it is a distance away, or you have to use a shipper like UPS or
> > FEDEX
> > > > and
> > > > you ship the night before and then use their "Morning delivery" and
the
> > Cal
> > > > Lab is expecting your 732A. Same on the way back to you. Of course
> > you
> > > > could always strap another battery on the 732A and hook it up to the
> > "ext
> > > > power" plug to last longer. I have seen it done. The issue is to
get
> > the
> > > > Cal Lab to charge the extra battery before they ship the 732A back
to
> > you.
> > > >
> > > > When you remove and work on the battery pack always have the AC
> > power
> > > > plugged in. The "CAL" led will stay on because the 18.6 v regulated
> > supply
> > > > is working.
> > > >
> > > > The "CAL" light is to indicate that power has not been lost to
the
> > > > Reference Amp or other associated circuits. When the raw supply
> > (battery)
> > > > voltage drops below about 21 volts the "CAL" light will go out.
Below
> > that
> > > > voltage the heater circuits will not work correctly and the 18.6
volt
> > > > regulated supply will not regulate. The requirement is that the
> > Reference
> > > > Amp be kept "alive" at all times to maintain the output voltage that
> > was
> > > > measured at the time of the most recent Calibration or
Certification.
> > When
> > > > the semiconductor junctions are unbiased and cool off when power is
> > lost,
> > > > and then power is restored the result will be a different 10 volts
than
> > > > before the power failure. My experience is that after all of the
years
> > > > that
> > > > these units have been powered up, this won't happen and when power
is
> > lost
> > > > and then restored, even months later, the 732A will come back to
almost
> > > > exactly the same 10 volts as when they lost power, usually with in
0.2
> > PPM
> > > > after 24 hours of "warm up".
> > > >
> > > > What type of hookup leads are you using when measuring the 1
volt
> > > > output? What is the PLC set to? I always use 100 PLC to measure
this.
> > If
> > > > you don't have "low thermal" connection leads you can experience uV
> > changes
> > > > for a minute or more after plugging in the leads due to the
"thermals"
> > > > generated because of the difference in temperature between the
banana
> > jacks
> > > > on the 732A and the banana plugs of the leads. I have found that
even
> > just
> > > > plugging in the lead will generate a thermal difference because of
> > > > difference of temps and some heating due to the physical act of just
> > > > inserting the plug because of friction between the jack and plug (my
> > theory
> > > > at any rate). You have to allow at least a minute or more before
being
> > > > able
> > > > to make a measurement after plugging in the leads. I just measured
the
> > > > variation of the 1 volt output of my 732A and using my 3458A and I
got
> > a
> > > > total difference of 0.159 uV over 40 measurements using 100 PLC on
the
> > 1
> > > > volt range of the 3458A. Using the MATH function and all of the
data
> > you
> > > > can collect. That was after waiting for several minutes after
plugging
> > in
> > > > the leads.
> > > >
> > > > I hope all of this helps.
> > > >
> > > > Bill
> > > >
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: "Randy Evans" <randyevans2...@gmail.com>
> > > > To: "Discussion of precise voltage measurement" <volt-nuts@febo.com>
> > > > Sent: Friday, August 22, 2014 9:03 PM
> > > > Subject: Re: [volt-nuts] 732A and Prologix received
> > > >
> > > >
> > > > > Todd,
> > > > >
> > > > > Thanks for the info. I have several Panasonic 12V 7 AH batteries
> > that
> > I
> > > > > keep topped off and they have very low current draw (~2 to 3 mA at
> > 13.5
> > > > > VDC) when charged and at their float voltage, so I am pretty sure
> > they
> > > > are
> > > > > in good condition. I will look at getting those in the units
after I
> > > > > ascertain the condition of the 732.
> > > > >
> > > > > So now I have a what appears to be a functioning 3458A and a 732A
but
> > > > they
> > > > > slightly disagree. I am like the man with two watches that
disagree
> > on
> > > > the
> > > > > time - which is correct? For the moment, i am only concerned
with
> > > > > stability. The need for absolute accuracy will come later.
> > > > >
> > > > > Randy
> > > > >
> > > > >
> > > > > On Fri, Aug 22, 2014 at 8:06 PM, Todd Micallef
<tmical...@gmail.com>
> > > > wrote:
> > > > >
> > > > > > Randy,
> > > > > >
> > > > > > You have two possible choices. It can be configured with 4 x 6v
4Ah
> > > > > > batteries or 2 x 12v 7Ah batteries. Hopefully the previous owner
> > has
> > > > > > modified the battery pack already. A couple of mine needed a
> > nibbler
> > > > tool
> > > > > > to remove enough of the aluminum cover that fits over the tops
of
> > the
> > > > > > batteries. The original cover will short out to the battery tabs
> > > > regardless
> > > > > > of the battery configuration if this is not done.
> > > > > >
> > > > > > You can find larger capacity batteries that will give you
slightly
> > more
> > > > > > battery life. I lost a couple sets of mail-order batteries after
a
> > few
> > > > > > extended outages. I would recommend going with locally bought
> > batteries
> > > > > > instead of the cheaper mail order. My local Batteries Plus will
> > > > typically
> > > > > > have some warranty if I remember correctly. Moving forward I
will
> > only
> > > > use
> > > > > > 2 12v batteries and pre-charge them on a battery charger to
> > equalize
> > > > them
> > > > > > before putting them in the 732A. I think the cheap batteries did
> > not
> > > > > > discharge equally, and would not recover when power was applied.
> > > > > >
> > > > > > Inspect the back plane for damaged traces and look at the
> > capacitors. I
> > > > had
> > > > > > a few that looked questionable. So far, I have replaced all the
big
> > > > caps
> > > > on
> > > > > > the pre-regulator and regulator boards. My feeling is that once
> > these
> > > > go
> > > > > > online, they should run as long as possible between repairs.
> > > > > >
> > > > > > The battery charger circuit may need adjusting. I tweaked mine
and
> > it
> > > > > > seemed to work fine.
> > > > > >
> > > > > > Todd
> > > > > >
> > > > > >
> > > > > > On Fri, Aug 22, 2014 at 10:42 PM, Randy Evans <
> > > > randyevans2...@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > > > I received my Fluke 732A today. Just powered it up but it
needs
> > new
> > > > > > > batteries. Any suggestions for sources (I haven't opened up
the
> > unit
> > > > > > yet -
> > > > > > > I want to make sure it works before doing that). Also
received
> > the
> > > > > > > ProLogix USB-GPIB adapter. I plan on using Mark Sims' CAL ran
> > data
> > > > > > dumper
> > > > > > > program to get the CAL data from my 3458A. Should be a busy
> > weekend.
> > > > > > >
> > > > > > > Randy
> > > > > > > _______________________________________________
> > > > > > > volt-nuts mailing list -- volt-nuts@febo.com
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> > > > > > > and follow the instructions there.
> > > > > > >
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