Hi

I'm also using the RCM6700 so this issue interests me.

I have a few thoughts....

1) There is an BAT54 Schottky diode inline with the Ext Bat signal on the RCM6700 board, so need to add your own external diode. This will give you some extra run time.

2) The Battery should only be supplying current when the main board has no power, so the battery life is based on how long the unit is unpowered (in my case, it will be powered most of the time)

3) There is an additional 100K series resistor on the RCM6700 for the 6000's VBATIO input. So you've really got 220K for the VBATIO. This may be too much.

4) The Ext Bat supply powers a 1.2V regulator for the RCM6000's VRAM input. So, any resistance you add is reducing the available supply to this chip. You really have 2V overhead in your scenario (3.6 - 0.4 - 1.2), so with a 150K resistor any current draw over 13.3uA will shut down the regulator.

I'd consider a smaller resistance, and then actually measure the current draw.

However, your tests have made me go back an re-evaluate my own battery supply :)

Phil.

--- In r..., Steve Trigero wrote:
>
> There is a known bug in the die of the R6000 cpu that causes the excessive current for
> the time-of-day clock. While 25ua is better, it will still kill your battery too soon for my
> taste.
>
> We remedied the problem by adding our own TOD clock chip to the motherboard.
> A PCF8563 from NXP. It draws about 650na over temperature. On bootup I read the
> PCF8563 and set the R6k's TOD clock to match it. Then I just use the built-in clock
> functions.
>
> Steve
>
>
> >________________________________
> > From: morton_street
> >To: r...
> >Sent: Tuesday, August 13, 2013 11:03 AM
> >Subject: [rabbit-semi] Re: Battery for RCM6700
> >
> >
> >
> >
> >
> >All,
> >
> >I have a RCM6700 Deluxe Develop Kit. The 120uA current drain for the bbram and rtc on the rcm6700 is not friendly. I have not found the source of the 120uA specification except in this forum. The docs I have say TBD. I ran some tests that show that the actual value is quite a bit lower; around 25uA @ room temperature. What is the original source for this number? Has anyone else run any empirical tests?
> >
> >My test for reference;
> >
> >* connect a 3.6V SAFT LS14250 battery thru a 1N4005 diode to a 120Kohm resistor. The negative battery terminal was connected to J4-2 on the proto board with the resistor connected to J4-1.
> >
> >* modified the samples\RTC_TEST.c program to also include a bbram variable. The bbram location was printed to the stdio window, then initialized and printed again.
> >
> >* 1st time running the program the bbram variable was un-initialized garbage. After init, it would retain the init value as long as the battery ciruit was in place. If battery circuit was removed, 1st print was garbage again. RTC values were retained/erased in same way.
> >
> >* The 120K resistor limited the current as follows:
> >NOTE: voltage drop across diode was 0.4V
> >
> >3.2V/120,000 = 27uA
> >
> >* memory & RTC operated correctly until resistance was raise to 150Kohm
> >
> >Dave
> >
> >--- In mailto:rabbit-semi%40yahoogroups.com, "seecwriter" wrote:
> >>
> >> Mario,
> >>
> >> We just did the same thing, we added a separate RTC chip to our
> >> motherboard that should last over 10-years on the battery. On boot-up
> >> I set the Rabbit clock from the off-board clock so I can continue to
> >> use the DC built-in features for time.
> >>
> >> Thanks,
> >> Steve
> >>
> >> --- In mailto:rabbit-semi%40yahoogroups.com, "mario_wtbbh" wrote:
> >> >
> >> > Hey Steve,
> >> >
> >> > I just noticed this post now.
> >> >
> >> > We raised the high RCM6700 VBat problem with Digi back in March and this was confirmed as a hardware problem. Initially the fix (new modules) was expected around July, but now they are saying "Christmas".
> >> >
> >> > As a back-stop, we added a separate SPI RTC chip that draws about 2uA and are using a 1000mAh battery (Renata CR2477) (with a jumper to VBat) on sites that are usually powered, with short periods on battery.
> >> >
> >> > I've had to convert all our data storage to flash, with ring buffers to avoid "wearing out" the flash.
> >> >
> >> > This itself has lots of side-issues (e.g. Needing to mount/dismount the flash to commit the flash table, which lives in battery-backed RAM).
> >> >
> >> > Regards,
> >> > Mario
> >> >
> >> >
> >> > --- In mailto:rabbit-semi%40yahoogroups.com, "seecwriter" wrote:
> >> > >
> >> > > That's not a bad choice. But it's half the capacity I need for a
> >> > > 5-year life, unless I'm over thinking this.
> >> > >
> >> > > We may have to go to a separate time-of-day clock device that uses
> >> > > far less current than the RCM6700's 120ua in order to get the life
> >> > > span we want with a reasonable size battery.
> >> > >
> >> > > Steve
> >> > >
> >> > > --- In mailto:rabbit-semi%40yahoogroups.com, "Moore, Robert" wrote:
> >> > > >
> >> > > > On the OP7200 I used a AA 3.6 VDC lithium battery (Saft LS14500CBA or
> >> > > > equivalent) accessible from the outside of the instrument case using a
> >> > > > Bulgin 122-BX0011/1 . . . I'm assuming the RCM6700 has the same pinout
> >> > > > for this. My biggest concern was to keep the end-user from opening the
> >> > > > instrument.
> >> > > >
> >> > > > bob
> >> > > > --
> >> > > > Robert K Moore, PhD
> >> > > > Designer, Macular Metrics
> >> > > > Robert_Moore@
> >> > > > 401-226-6888
> >> > > >
> >> > > >
> >> > > >
> >> > > >
> >> > > > On Thu, Aug 16, 2012 at 12:31 PM, seecwriter wrote:
> >> > > >
> >> > > > > The battery current draw for the RCM6700 seems rather high, requiring a
> >> > > > > large battery to maintain the clock for 5-years.
> >> > > > > Can anything be done to reduce the battery current? I'm just rying to
> >> > > > > maintain the time-of-clock.
> >> > > > > What have others done for a battery?
> >> > > > >
> >> > > > > Steve
> >> > > > >
> >> > > > >
> >> > > > >
> >> > > > >
> >> > > > >
> >> > > > >

There is a known bug in the die of the R6000 cpu that causes the excessive current for
the time-of-day clock. While 25ua is better, it will still kill your battery too soon for my
taste.

We remedied the problem by adding our own TOD clock chip to the motherboard.
A PCF8563 from NXP. It draws about 650na over temperature. On bootup I read the
PCF8563 and set the R6k's TOD clock to match it. Then I just use the built-in clock
functions.

Steve
>________________________________
> From: morton_street
>To: r...
>Sent: Tuesday, August 13, 2013 11:03 AM
>Subject: [rabbit-semi] Re: Battery for RCM6700
>
>
>
>All,
>
>I have a RCM6700 Deluxe Develop Kit. The 120uA current drain for the bbram and rtc on the rcm6700 is not friendly. I have not found the source of the 120uA specification except in this forum. The docs I have say TBD. I ran some tests that show that the actual value is quite a bit lower; around 25uA @ room temperature. What is the original source for this number? Has anyone else run any empirical tests?
>
>My test for reference;
>
>* connect a 3.6V SAFT LS14250 battery thru a 1N4005 diode to a 120Kohm resistor. The negative battery terminal was connected to J4-2 on the proto board with the resistor connected to J4-1.
>
>* modified the samples\RTC_TEST.c program to also include a bbram variable. The bbram location was printed to the stdio window, then initialized and printed again.
>
>* 1st time running the program the bbram variable was un-initialized garbage. After init, it would retain the init value as long as the battery ciruit was in place. If battery circuit was removed, 1st print was garbage again. RTC values were retained/erased in same way.
>
>* The 120K resistor limited the current as follows:
>NOTE: voltage drop across diode was 0.4V
>
>3.2V/120,000 = 27uA
>
>* memory & RTC operated correctly until resistance was raise to 150Kohm
>
>Dave
>
>--- In mailto:rabbit-semi%40yahoogroups.com, "seecwriter" wrote:
>>
>> Mario,
>>
>> We just did the same thing, we added a separate RTC chip to our
>> motherboard that should last over 10-years on the battery. On boot-up
>> I set the Rabbit clock from the off-board clock so I can continue to
>> use the DC built-in features for time.
>>
>> Thanks,
>> Steve
>>
>> --- In mailto:rabbit-semi%40yahoogroups.com, "mario_wtbbh" wrote:
>> >
>> > Hey Steve,
>> >
>> > I just noticed this post now.
>> >
>> > We raised the high RCM6700 VBat problem with Digi back in March and this was confirmed as a hardware problem. Initially the fix (new modules) was expected around July, but now they are saying "Christmas".
>> >
>> > As a back-stop, we added a separate SPI RTC chip that draws about 2uA and are using a 1000mAh battery (Renata CR2477) (with a jumper to VBat) on sites that are usually powered, with short periods on battery.
>> >
>> > I've had to convert all our data storage to flash, with ring buffers to avoid "wearing out" the flash.
>> >
>> > This itself has lots of side-issues (e.g. Needing to mount/dismount the flash to commit the flash table, which lives in battery-backed RAM).
>> >
>> > Regards,
>> > Mario
>> >
>> >
>> > --- In mailto:rabbit-semi%40yahoogroups.com, "seecwriter" wrote:
>> > >
>> > > That's not a bad choice. But it's half the capacity I need for a
>> > > 5-year life, unless I'm over thinking this.
>> > >
>> > > We may have to go to a separate time-of-day clock device that uses
>> > > far less current than the RCM6700's 120ua in order to get the life
>> > > span we want with a reasonable size battery.
>> > >
>> > > Steve
>> > >
>> > > --- In mailto:rabbit-semi%40yahoogroups.com, "Moore, Robert" wrote:
>> > > >
>> > > > On the OP7200 I used a AA 3.6 VDC lithium battery (Saft LS14500CBA or
>> > > > equivalent) accessible from the outside of the instrument case using a
>> > > > Bulgin 122-BX0011/1 . . . I'm assuming the RCM6700 has the same pinout
>> > > > for this. My biggest concern was to keep the end-user from opening the
>> > > > instrument.
>> > > >
>> > > > bob
>> > > > --
>> > > > Robert K Moore, PhD
>> > > > Designer, Macular Metrics
>> > > > Robert_Moore@
>> > > > 401-226-6888
>> > > >
>> > > >
>> > > >
>> > > >
>> > > > On Thu, Aug 16, 2012 at 12:31 PM, seecwriter wrote:
>> > > >
>> > > > > The battery current draw for the RCM6700 seems rather high, requiring a
>> > > > > large battery to maintain the clock for 5-years.
>> > > > > Can anything be done to reduce the battery current? I'm just rying to
>> > > > > maintain the time-of-clock.
>> > > > > What have others done for a battery?
>> > > > >
>> > > > > Steve
>> > > > >
>> > > > >
>> > > > >
>> > > > >
>> > > > >
>> > > > > Yahoo! Groups Links
>> > > > >
>> > > > >
>> > > > >
>> > > > >
>> > > >
>> > >
>> >
>>
>

All,

I have a RCM6700 Deluxe Develop Kit. The 120uA current drain for the bbram and rtc on the rcm6700 is not friendly. I have not found the source of the 120uA specification except in this forum. The docs I have say TBD. I ran some tests that show that the actual value is quite a bit lower; around 25uA @ room temperature. What is the original source for this number? Has anyone else run any empirical tests?

My test for reference;

* connect a 3.6V SAFT LS14250 battery thru a 1N4005 diode to a 120Kohm resistor. The negative battery terminal was connected to J4-2 on the proto board with the resistor connected to J4-1.

* modified the samples\RTC_TEST.c program to also include a bbram variable. The bbram location was printed to the stdio window, then initialized and printed again.

* 1st time running the program the bbram variable was un-initialized garbage. After init, it would retain the init value as long as the battery ciruit was in place. If battery circuit was removed, 1st print was garbage again. RTC values were retained/erased in same way.

* The 120K resistor limited the current as follows:
NOTE: voltage drop across diode was 0.4V

3.2V/120,000 = 27uA

* memory & RTC operated correctly until resistance was raise to 150Kohm

Dave

--- In r..., "seecwriter" wrote:
>
> Mario,
>
> We just did the same thing, we added a separate RTC chip to our
> motherboard that should last over 10-years on the battery. On boot-up
> I set the Rabbit clock from the off-board clock so I can continue to
> use the DC built-in features for time.
>
> Thanks,
> Steve
>
> --- In r..., "mario_wtbbh" wrote:
> >
> > Hey Steve,
> >
> > I just noticed this post now.
> >
> > We raised the high RCM6700 VBat problem with Digi back in March and this was confirmed as a hardware problem. Initially the fix (new modules) was expected around July, but now they are saying "Christmas".
> >
> > As a back-stop, we added a separate SPI RTC chip that draws about 2uA and are using a 1000mAh battery (Renata CR2477) (with a jumper to VBat) on sites that are usually powered, with short periods on battery.
> >
> > I've had to convert all our data storage to flash, with ring buffers to avoid "wearing out" the flash.
> >
> > This itself has lots of side-issues (e.g. Needing to mount/dismount the flash to commit the flash table, which lives in battery-backed RAM).
> >
> > Regards,
> > Mario
> >
> >
> > --- In r..., "seecwriter" wrote:
> > >
> > > That's not a bad choice. But it's half the capacity I need for a
> > > 5-year life, unless I'm over thinking this.
> > >
> > > We may have to go to a separate time-of-day clock device that uses
> > > far less current than the RCM6700's 120ua in order to get the life
> > > span we want with a reasonable size battery.
> > >
> > > Steve
> > >
> > > --- In r..., "Moore, Robert" wrote:
> > > >
> > > > On the OP7200 I used a AA 3.6 VDC lithium battery (Saft LS14500CBA or
> > > > equivalent) accessible from the outside of the instrument case using a
> > > > Bulgin 122-BX0011/1 . . . I'm assuming the RCM6700 has the same pinout
> > > > for this. My biggest concern was to keep the end-user from opening the
> > > > instrument.
> > > >
> > > > bob
> > > > --
> > > > Robert K Moore, PhD
> > > > Designer, Macular Metrics
> > > > Robert_Moore@
> > > > 401-226-6888
> > > >
> > > >
> > > >
> > > >
> > > > On Thu, Aug 16, 2012 at 12:31 PM, seecwriter wrote:
> > > >
> > > > > The battery current draw for the RCM6700 seems rather high, requiring a
> > > > > large battery to maintain the clock for 5-years.
> > > > > Can anything be done to reduce the battery current? I'm just rying to
> > > > > maintain the time-of-clock.
> > > > > What have others done for a battery?
> > > > >
> > > > > Steve
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >

Mario,

We just did the same thing, we added a separate RTC chip to our
motherboard that should last over 10-years on the battery. On boot-up
I set the Rabbit clock from the off-board clock so I can continue to
use the DC built-in features for time.

Thanks,
Steve

--- In r..., "mario_wtbbh" wrote:
>
> Hey Steve,
>
> I just noticed this post now.
>
> We raised the high RCM6700 VBat problem with Digi back in March and this was confirmed as a hardware problem. Initially the fix (new modules) was expected around July, but now they are saying "Christmas".
>
> As a back-stop, we added a separate SPI RTC chip that draws about 2uA and are using a 1000mAh battery (Renata CR2477) (with a jumper to VBat) on sites that are usually powered, with short periods on battery.
>
> I've had to convert all our data storage to flash, with ring buffers to avoid "wearing out" the flash.
>
> This itself has lots of side-issues (e.g. Needing to mount/dismount the flash to commit the flash table, which lives in battery-backed RAM).
>
> Regards,
> Mario
> --- In r..., "seecwriter" wrote:
> >
> > That's not a bad choice. But it's half the capacity I need for a
> > 5-year life, unless I'm over thinking this.
> >
> > We may have to go to a separate time-of-day clock device that uses
> > far less current than the RCM6700's 120ua in order to get the life
> > span we want with a reasonable size battery.
> >
> > Steve
> >
> > --- In r..., "Moore, Robert" wrote:
> > >
> > > On the OP7200 I used a AA 3.6 VDC lithium battery (Saft LS14500CBA or
> > > equivalent) accessible from the outside of the instrument case using a
> > > Bulgin 122-BX0011/1 . . . I'm assuming the RCM6700 has the same pinout
> > > for this. My biggest concern was to keep the end-user from opening the
> > > instrument.
> > >
> > > bob
> > > --
> > > Robert K Moore, PhD
> > > Designer, Macular Metrics
> > > Robert_Moore@
> > > 401-226-6888
> > >
> > >
> > >
> > >
> > > On Thu, Aug 16, 2012 at 12:31 PM, seecwriter wrote:
> > >
> > > > The battery current draw for the RCM6700 seems rather high, requiring a
> > > > large battery to maintain the clock for 5-years.
> > > > Can anything be done to reduce the battery current? I'm just rying to
> > > > maintain the time-of-clock.
> > > > What have others done for a battery?
> > > >
> > > > Steve
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >

Hey Steve,

I just noticed this post now.

We raised the high RCM6700 VBat problem with Digi back in March and this was confirmed as a hardware problem. Initially the fix (new modules) was expected around July, but now they are saying "Christmas".

As a back-stop, we added a separate SPI RTC chip that draws about 2uA and are using a 1000mAh battery (Renata CR2477) (with a jumper to VBat) on sites that are usually powered, with short periods on battery.

I've had to convert all our data storage to flash, with ring buffers to avoid "wearing out" the flash.

This itself has lots of side-issues (e.g. Needing to mount/dismount the flash to commit the flash table, which lives in battery-backed RAM).

Regards,
Mario
--- In r..., "seecwriter" wrote:
>
> That's not a bad choice. But it's half the capacity I need for a
> 5-year life, unless I'm over thinking this.
>
> We may have to go to a separate time-of-day clock device that uses
> far less current than the RCM6700's 120ua in order to get the life
> span we want with a reasonable size battery.
>
> Steve
>
> --- In r..., "Moore, Robert" wrote:
> >
> > On the OP7200 I used a AA 3.6 VDC lithium battery (Saft LS14500CBA or
> > equivalent) accessible from the outside of the instrument case using a
> > Bulgin 122-BX0011/1 . . . I'm assuming the RCM6700 has the same pinout
> > for this. My biggest concern was to keep the end-user from opening the
> > instrument.
> >
> > bob
> > --
> > Robert K Moore, PhD
> > Designer, Macular Metrics
> > Robert_Moore@
> > 401-226-6888
> >
> >
> >
> >
> > On Thu, Aug 16, 2012 at 12:31 PM, seecwriter wrote:
> >
> > > The battery current draw for the RCM6700 seems rather high, requiring a
> > > large battery to maintain the clock for 5-years.
> > > Can anything be done to reduce the battery current? I'm just rying to
> > > maintain the time-of-clock.
> > > What have others done for a battery?
> > >
> > > Steve
> > >
> > >
> > >
> > >
> > >
> > >

5-years is not that long. How long does the battery in your PC last?
If you had to replace the battery in your PC every 3-months or so,
would that be a problem? Besides, our products are sealed and not
meant to be opened by customers. Like Apple products. Open it and
your warranty is void.

The Rabbit is Ethernet enabled, but our customers keep our products
on private networks that have no access to the outside world. You
wouldn't want some hacker shutting down your satellite TV broadcast
would you? People get real upset when their TV goes off the air.

Rechargeable is also not an option. One, you have to open the box,
which is a no-no. Two, our customers fear the possibility of
explosion.

Accurate time and date is important for the logs we maintain.

It's looking more and more like we are going to have to use a separate
clock device to get reasonable battery life. Something like a PCF8563.
It uses 400na over a temperature range of -40C to +85C. Using a .4AH
lithium coin battery, we can get better than 10-years of life.

--- In r..., Phil D wrote:
>
> I do recall the manual saying something about cycling the power to get
> better RTC current draw performance,
> 5 years is a long time to want the RTC to survive is a rechargeable 3V not
> an option is it realistic that the product will be un-powered for this
> period and require the correct time? as this is a network device NTC may be
> a possibility to explore
> I use a 3V lithium ion that i calculated as 72 days RTC time which is
> suitable for my application as real time isn't essential
>
> Phil
>
> On 16 August 2012 20:39, Moore, Robert wrote:
>
> > **
> >
> >
> > I noticed somewhere in the 6700 manual a REQUIREMENT that you cycle power
> > to the 6700 AFTER attaching the battery. This affects the drain on the
> > battery . . .
> >
> > bob
> >
> > On Thu, Aug 16, 2012 at 1:45 PM, seecwriter wrote:
> >
> >> That's not a bad choice. But it's half the capacity I need for a
> >> 5-year life, unless I'm over thinking this.
> >>
> >> We may have to go to a separate time-of-day clock device that uses
> >> far less current than the RCM6700's 120ua in order to get the life
> >> span we want with a reasonable size battery.
> >>
> >> Steve
> >>
> >> --- In r..., "Moore, Robert"
> >> wrote:
> >> >
> >> > On the OP7200 I used a AA 3.6 VDC lithium battery (Saft LS14500CBA or
> >> > equivalent) accessible from the outside of the instrument case using a
> >> > Bulgin 122-BX0011/1 . . . I'm assuming the RCM6700 has the same pinout
> >> > for this. My biggest concern was to keep the end-user from opening the
> >> > instrument.
> >> >
> >> > bob
> >> > --
> >> > Robert K Moore, PhD
> >> > Designer, Macular Metrics
> >> > Robert_Moore@
> >> > 401-226-6888
> >> >
> >> >
> >> >
> >> >
> >> > On Thu, Aug 16, 2012 at 12:31 PM, seecwriter wrote:
> >> >
> >> > > The battery current draw for the RCM6700 seems rather high, requiring
> >> a
> >> > > large battery to maintain the clock for 5-years.
> >> > > Can anything be done to reduce the battery current? I'm just rying to
> >> > > maintain the time-of-clock.
> >> > > What have others done for a battery?
> >> > >
> >> > > Steve
> >> > >
> >> > >
> >> > >
> >> > >
> >> > >
> >> > >

We use a super capacitor to provide the clock battery voltage, it is
recharged when the unit is powered up and saves us having to worry about
battery replacements.

Brian

From: r... [mailto:r...] On
Behalf Of Moore, Robert
Sent: Thursday, August 16, 2012 5:13 PM
To: r...
Subject: Re: [rabbit-semi] Re: Battery for RCM6700

I haven't calculated the life for your hardware. In my app using the OP7200
and the battery I mentioned I calculated the life at > 15 years. My real
intent was to keep the end user from ever opening the instrument.

bob

On Thu, Aug 16, 2012 at 7:45 PM, Phil D wrote:

I do recall the manual saying something about cycling the power to get
better RTC current draw performance,

5 years is a long time to want the RTC to survive is a rechargeable 3V not
an option is it realistic that the product will be un-powered for this
period and require the correct time? as this is a network device NTC may be
a possibility to explore

I use a 3V lithium ion that i calculated as 72 days RTC time which is
suitable for my application as real time isn't essential

Phil

On 16 August 2012 20:39, Moore, Robert wrote:

I noticed somewhere in the 6700 manual a REQUIREMENT that you cycle power to
the 6700 AFTER attaching the battery. This affects the drain on the battery
. . .

bob

On Thu, Aug 16, 2012 at 1:45 PM, seecwriter wrote:

That's not a bad choice. But it's half the capacity I need for a
5-year life, unless I'm over thinking this.

We may have to go to a separate time-of-day clock device that uses
far less current than the RCM6700's 120ua in order to get the life
span we want with a reasonable size battery.

Steve

--- In r..., "Moore, Robert"
wrote:
>
> On the OP7200 I used a AA 3.6 VDC lithium battery (Saft LS14500CBA or
> equivalent) accessible from the outside of the instrument case using a
> Bulgin 122-BX0011/1 . . . I'm assuming the RCM6700 has the same pinout
> for this. My biggest concern was to keep the end-user from opening the
> instrument.
>
> bob
> --
> Robert K Moore, PhD
> Designer, Macular Metrics
> Robert_Moore@...
> 401-226-6888
> On Thu, Aug 16, 2012 at 12:31 PM, seecwriter wrote:
>
> > The battery current draw for the RCM6700 seems rather high, requiring a
> > large battery to maintain the clock for 5-years.
> > Can anything be done to reduce the battery current? I'm just rying to
> > maintain the time-of-clock.
> > What have others done for a battery?
> >
> > Steve
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
>

Yahoo! Groups Links

--
Robert K Moore, PhD
Designer, Macular Metrics

R...@brown.edu
401-226-6888

--
Robert K Moore, PhD
Designer, Macular Metrics
R...@brown.edu
401-226-6888

I haven't calculated the life for your hardware. In my app using the OP7200
and the battery I mentioned I calculated the life at > 15 years. My real
intent was to keep the end user from ever opening the instrument.

bob

On Thu, Aug 16, 2012 at 7:45 PM, Phil D wrote:

> I do recall the manual saying something about cycling the power to get
> better RTC current draw performance,
> 5 years is a long time to want the RTC to survive is a rechargeable 3V not
> an option is it realistic that the product will be un-powered for this
> period and require the correct time? as this is a network device NTC may be
> a possibility to explore
> I use a 3V lithium ion that i calculated as 72 days RTC time which is
> suitable for my application as real time isn't essential
>
> Phil
>
> On 16 August 2012 20:39, Moore, Robert wrote:
>
>> **
>> I noticed somewhere in the 6700 manual a REQUIREMENT that you cycle power
>> to the 6700 AFTER attaching the battery. This affects the drain on the
>> battery . . .
>>
>> bob
>>
>> On Thu, Aug 16, 2012 at 1:45 PM, seecwriter wrote:
>>
>>> That's not a bad choice. But it's half the capacity I need for a
>>> 5-year life, unless I'm over thinking this.
>>>
>>> We may have to go to a separate time-of-day clock device that uses
>>> far less current than the RCM6700's 120ua in order to get the life
>>> span we want with a reasonable size battery.
>>>
>>> Steve
>>>
>>> --- In r..., "Moore, Robert"
>>> wrote:
>>> >
>>> > On the OP7200 I used a AA 3.6 VDC lithium battery (Saft LS14500CBA or
>>> > equivalent) accessible from the outside of the instrument case using a
>>> > Bulgin 122-BX0011/1 . . . I'm assuming the RCM6700 has the same
>>> pinout
>>> > for this. My biggest concern was to keep the end-user from opening the
>>> > instrument.
>>> >
>>> > bob
>>> > --
>>> > Robert K Moore, PhD
>>> > Designer, Macular Metrics
>>> > Robert_Moore@...
>>> > 401-226-6888
>>> >
>>> >
>>> >
>>> >
>>> > On Thu, Aug 16, 2012 at 12:31 PM, seecwriter wrote:
>>> >
>>> > > The battery current draw for the RCM6700 seems rather high,
>>> requiring a
>>> > > large battery to maintain the clock for 5-years.
>>> > > Can anything be done to reduce the battery current? I'm just rying to
>>> > > maintain the time-of-clock.
>>> > > What have others done for a battery?
>>> > >
>>> > > Steve
>>> > >
>>> > >
>>> > >
>>> > >
>>> > >
>>> > > Yahoo! Groups Links
>>> > >
>>> > >
>>> > >
>>> > >
>>> >
>>>
>>>
>>>
>>>
>>>
>>>
>>> Yahoo! Groups Links
>>>
>>>
>>>
>>>
>> --
>> Robert K Moore, PhD
>> Designer, Macular Metrics
>> R...@brown.edu
>> 401-226-6888
>>
>

--
Robert K Moore, PhD
Designer, Macular Metrics
R...@brown.edu
401-226-6888

I do recall the manual saying something about cycling the power to get
better RTC current draw performance,
5 years is a long time to want the RTC to survive is a rechargeable 3V not
an option is it realistic that the product will be un-powered for this
period and require the correct time? as this is a network device NTC may be
a possibility to explore
I use a 3V lithium ion that i calculated as 72 days RTC time which is
suitable for my application as real time isn't essential

Phil

On 16 August 2012 20:39, Moore, Robert wrote:

> **
> I noticed somewhere in the 6700 manual a REQUIREMENT that you cycle power
> to the 6700 AFTER attaching the battery. This affects the drain on the
> battery . . .
>
> bob
>
> On Thu, Aug 16, 2012 at 1:45 PM, seecwriter wrote:
>
>> That's not a bad choice. But it's half the capacity I need for a
>> 5-year life, unless I'm over thinking this.
>>
>> We may have to go to a separate time-of-day clock device that uses
>> far less current than the RCM6700's 120ua in order to get the life
>> span we want with a reasonable size battery.
>>
>> Steve
>>
>> --- In r..., "Moore, Robert"
>> wrote:
>> >
>> > On the OP7200 I used a AA 3.6 VDC lithium battery (Saft LS14500CBA or
>> > equivalent) accessible from the outside of the instrument case using a
>> > Bulgin 122-BX0011/1 . . . I'm assuming the RCM6700 has the same pinout
>> > for this. My biggest concern was to keep the end-user from opening the
>> > instrument.
>> >
>> > bob
>> > --
>> > Robert K Moore, PhD
>> > Designer, Macular Metrics
>> > Robert_Moore@...
>> > 401-226-6888
>> >
>> >
>> >
>> >
>> > On Thu, Aug 16, 2012 at 12:31 PM, seecwriter wrote:
>> >
>> > > The battery current draw for the RCM6700 seems rather high, requiring
>> a
>> > > large battery to maintain the clock for 5-years.
>> > > Can anything be done to reduce the battery current? I'm just rying to
>> > > maintain the time-of-clock.
>> > > What have others done for a battery?
>> > >
>> > > Steve
>> > >
>> > >
>> > >
>> > >
>> > >
>> > > Yahoo! Groups Links
>> > >
>> > >
>> > >
>> > >
>> >
>>
>>
>> Yahoo! Groups Links
> --
> Robert K Moore, PhD
> Designer, Macular Metrics
> R...@brown.edu
> 401-226-6888
>
>
>

I noticed somewhere in the 6700 manual a REQUIREMENT that you cycle power
to the 6700 AFTER attaching the battery. This affects the drain on the
battery . . .

bob

On Thu, Aug 16, 2012 at 1:45 PM, seecwriter wrote:

> That's not a bad choice. But it's half the capacity I need for a
> 5-year life, unless I'm over thinking this.
>
> We may have to go to a separate time-of-day clock device that uses
> far less current than the RCM6700's 120ua in order to get the life
> span we want with a reasonable size battery.
>
> Steve
>
> --- In r..., "Moore, Robert"
> wrote:
> >
> > On the OP7200 I used a AA 3.6 VDC lithium battery (Saft LS14500CBA or
> > equivalent) accessible from the outside of the instrument case using a
> > Bulgin 122-BX0011/1 . . . I'm assuming the RCM6700 has the same pinout
> > for this. My biggest concern was to keep the end-user from opening the
> > instrument.
> >
> > bob
> > --
> > Robert K Moore, PhD
> > Designer, Macular Metrics
> > Robert_Moore@...
> > 401-226-6888
> >
> >
> >
> >
> > On Thu, Aug 16, 2012 at 12:31 PM, seecwriter wrote:
> >
> > > The battery current draw for the RCM6700 seems rather high, requiring a
> > > large battery to maintain the clock for 5-years.
> > > Can anything be done to reduce the battery current? I'm just rying to
> > > maintain the time-of-clock.
> > > What have others done for a battery?
> > >
> > > Steve
> > >
> > >
> > >
> > >
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> >
>
>
> Yahoo! Groups Links
--
Robert K Moore, PhD
Designer, Macular Metrics
R...@brown.edu
401-226-6888