Is there any way to tell when the function key routine is complete? In the case of taking multiple readings using the DEFKEY and MATH function, I don't see any indication when the routine is complete. In one particular case, I am taking a 100 readings with NLPC set for 1000 so its a long while before it's complete, but i have to guess when it's done.
Thanks, Randy On Sun, Aug 24, 2014 at 6:04 PM, Randy Evans <[email protected]> wrote: > 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 <[email protected]> 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" <[email protected]> >> To: "Discussion of precise voltage measurement" <[email protected]> >> 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 <[email protected]> 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" <[email protected]> >> > > To: "Discussion of precise voltage measurement" <[email protected]> >> > > 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 <[email protected] >> > >> > > 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 < >> > > [email protected]> >> > > > > 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 -- [email protected] >> > > > > > To unsubscribe, go to >> > > > > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >> > > > > > and follow the instructions there. >> > > > > > >> > > > > _______________________________________________ >> > > > > volt-nuts mailing list -- [email protected] >> > > > > To unsubscribe, go to >> > > > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >> > > > > and follow the instructions there. >> > > > > >> > > > _______________________________________________ >> > > > volt-nuts mailing list -- [email protected] >> > > > To unsubscribe, go to >> > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >> > > > and follow the instructions there. >> > > >> > > _______________________________________________ >> > > volt-nuts mailing list -- [email protected] >> > > To unsubscribe, go to >> > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >> > > and follow the instructions there. >> > > >> > _______________________________________________ >> > volt-nuts mailing list -- [email protected] >> > To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >> > and follow the instructions there. >> >> _______________________________________________ >> volt-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >> and follow the instructions there. >> > > _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
