1-Wire ADC...

D

David Lesher

Guest
Was looking for a way to monitor a number of 12V deep cycle L-A batteries.
Since we have an installed 1-Wire network, it would be nice if we could
just add on to that.

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?


--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that\'s close..........................
Unless the host (that isn\'t close).........................pob 1433
is busy, hung or dead....................................20915-1433
 
On Mon, 20 Jul 2020 18:22:12 +0000 (UTC), David Lesher
<wb8foz@panix.com> wrote:

Was looking for a way to monitor a number of 12V deep cycle L-A batteries.
Since we have an installed 1-Wire network, it would be nice if we could
just add on to that.

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?

Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be
 
On Mon, 20 Jul 2020 18:22:12 +0000 (UTC), David Lesher
<wb8foz@panix.com> wrote:

Was looking for a way to monitor a number of 12V deep cycle L-A batteries.
Since we have an installed 1-Wire network, it would be nice if we could
just add on to that.

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?

Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be
 
boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?

Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....

Common grounds are another obstacle. Hard to measure batteries in series...

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that\'s close..........................
Unless the host (that isn\'t close).........................pob 1433
is busy, hung or dead....................................20915-1433
 
boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?

Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....

Common grounds are another obstacle. Hard to measure batteries in series...

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that\'s close..........................
Unless the host (that isn\'t close).........................pob 1433
is busy, hung or dead....................................20915-1433
 
On Monday, July 20, 2020 at 8:42:33 PM UTC-4, David Lesher wrote:
boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?


Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....
I know nothing of ADCs, but isn\'t this successive approximation?
maybe you have the wrong search term?
George H.

Common grounds are another obstacle. Hard to measure batteries in series...

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that\'s close..........................
Unless the host (that isn\'t close).........................pob 1433
is busy, hung or dead....................................20915-1433
 
On Monday, July 20, 2020 at 8:42:33 PM UTC-4, David Lesher wrote:
boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?


Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....
I know nothing of ADCs, but isn\'t this successive approximation?
maybe you have the wrong search term?
George H.

Common grounds are another obstacle. Hard to measure batteries in series...

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that\'s close..........................
Unless the host (that isn\'t close).........................pob 1433
is busy, hung or dead....................................20915-1433
 
On Monday, July 20, 2020 at 8:42:33 PM UTC-4, David Lesher wrote:
boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?


Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....
I know nothing of ADCs, but isn\'t this successive approximation?
maybe you have the wrong search term?
George H.

Common grounds are another obstacle. Hard to measure batteries in series...

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that\'s close..........................
Unless the host (that isn\'t close).........................pob 1433
is busy, hung or dead....................................20915-1433
 
On 21/07/2020 04:25, Ricketty C wrote:
On Monday, July 20, 2020 at 2:22:16 PM UTC-4, David Lesher wrote:
Was looking for a way to monitor a number of 12V deep cycle L-A
batteries. Since we have an installed 1-Wire network, it would be
nice if we could just add on to that.

But I notice a dearth of 1-Wire ADC\'s. Any idea why?

Any digital device can be a 1-wire device. I would just program up a
cheap MCU with a built in ADC to be controlled over 1-wire. It just
takes a resistor and a cap to power it. No?

Making a 1-wire slave can be a bit fiddly, but it\'s perfectly possible,
yes. And if you are monitoring the power in the battery, you can surely
use that to power the microcontroller (your microcontroller is mostly in
sleep mode, and a tiny device will have lower power requirements than
most batteries\' leakage current).

If you don\'t need to conform to the Dallas 1-wire protocol, but merely
need communication over one wire, then it gets a lot simpler. You can
use a standard UART, tie TX and RX together with the TX pin in open
drain mode, and you\'ve probably got a good enough solution.

The MCU itself will cost practically nothing. The real cost is that
you\'ll need to program them.
 
On 21/07/2020 04:25, Ricketty C wrote:
On Monday, July 20, 2020 at 2:22:16 PM UTC-4, David Lesher wrote:
Was looking for a way to monitor a number of 12V deep cycle L-A
batteries. Since we have an installed 1-Wire network, it would be
nice if we could just add on to that.

But I notice a dearth of 1-Wire ADC\'s. Any idea why?

Any digital device can be a 1-wire device. I would just program up a
cheap MCU with a built in ADC to be controlled over 1-wire. It just
takes a resistor and a cap to power it. No?

Making a 1-wire slave can be a bit fiddly, but it\'s perfectly possible,
yes. And if you are monitoring the power in the battery, you can surely
use that to power the microcontroller (your microcontroller is mostly in
sleep mode, and a tiny device will have lower power requirements than
most batteries\' leakage current).

If you don\'t need to conform to the Dallas 1-wire protocol, but merely
need communication over one wire, then it gets a lot simpler. You can
use a standard UART, tie TX and RX together with the TX pin in open
drain mode, and you\'ve probably got a good enough solution.

The MCU itself will cost practically nothing. The real cost is that
you\'ll need to program them.
 
On 21/07/2020 04:25, Ricketty C wrote:
On Monday, July 20, 2020 at 2:22:16 PM UTC-4, David Lesher wrote:
Was looking for a way to monitor a number of 12V deep cycle L-A
batteries. Since we have an installed 1-Wire network, it would be
nice if we could just add on to that.

But I notice a dearth of 1-Wire ADC\'s. Any idea why?

Any digital device can be a 1-wire device. I would just program up a
cheap MCU with a built in ADC to be controlled over 1-wire. It just
takes a resistor and a cap to power it. No?

Making a 1-wire slave can be a bit fiddly, but it\'s perfectly possible,
yes. And if you are monitoring the power in the battery, you can surely
use that to power the microcontroller (your microcontroller is mostly in
sleep mode, and a tiny device will have lower power requirements than
most batteries\' leakage current).

If you don\'t need to conform to the Dallas 1-wire protocol, but merely
need communication over one wire, then it gets a lot simpler. You can
use a standard UART, tie TX and RX together with the TX pin in open
drain mode, and you\'ve probably got a good enough solution.

The MCU itself will cost practically nothing. The real cost is that
you\'ll need to program them.
 
On Tue, 21 Jul 2020 00:42:29 +0000 (UTC), David Lesher
<wb8foz@panix.com> wrote:

boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?


Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....

Common grounds are another obstacle. Hard to measure batteries in series...

Power each measuring unit locally from local battery and connect the
units in series into a single current loop using optoisolators. If
more or less standard UARTs are used, use two current loops. Connect a
scheduler transmitter to one loop and use it to address individual
measuring units (with Rx pins connected to the loop with
optoisolator). The addressed unit then sends measurement data by
interrupting the current flow in the other loop. A central monitor
then extract the data from that loop.

The drawback is that every unit must drive the Tx into Mark (20 mA)
Idle state to allow current pass from one station to the next. These
days with better optoisolators a much smaller loop current (say 2 mA)
could be used.

To get rid of the polling circuit, some CAN (Controller Area Network)
style current loop could be used (e.g. 2 mA recessive state and 0 V
dominant state) and let the nodes themselves handle the arbitration on
the same loop with both Tx and Rx isolators in the same loop for all
stations.
 
On Tue, 21 Jul 2020 00:42:29 +0000 (UTC), David Lesher
<wb8foz@panix.com> wrote:

boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?


Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....

Common grounds are another obstacle. Hard to measure batteries in series...

Power each measuring unit locally from local battery and connect the
units in series into a single current loop using optoisolators. If
more or less standard UARTs are used, use two current loops. Connect a
scheduler transmitter to one loop and use it to address individual
measuring units (with Rx pins connected to the loop with
optoisolator). The addressed unit then sends measurement data by
interrupting the current flow in the other loop. A central monitor
then extract the data from that loop.

The drawback is that every unit must drive the Tx into Mark (20 mA)
Idle state to allow current pass from one station to the next. These
days with better optoisolators a much smaller loop current (say 2 mA)
could be used.

To get rid of the polling circuit, some CAN (Controller Area Network)
style current loop could be used (e.g. 2 mA recessive state and 0 V
dominant state) and let the nodes themselves handle the arbitration on
the same loop with both Tx and Rx isolators in the same loop for all
stations.
 
On Tue, 21 Jul 2020 00:42:29 +0000 (UTC), David Lesher
<wb8foz@panix.com> wrote:

boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?


Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....

Common grounds are another obstacle. Hard to measure batteries in series...

I once invented a leapfrog matrix of current-limited SSRs to check a
series string of batteries. Odd/even nodes are switched to opposite
sides of a floating, bipolar ADC.

A couple more SSRs could make a flying-capacitor isolator.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On Tue, 21 Jul 2020 00:42:29 +0000 (UTC), David Lesher
<wb8foz@panix.com> wrote:

boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?


Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....

Common grounds are another obstacle. Hard to measure batteries in series...

I once invented a leapfrog matrix of current-limited SSRs to check a
series string of batteries. Odd/even nodes are switched to opposite
sides of a floating, bipolar ADC.

A couple more SSRs could make a flying-capacitor isolator.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On Tue, 21 Jul 2020 00:42:29 +0000 (UTC), David Lesher
<wb8foz@panix.com> wrote:

boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?


Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....

Common grounds are another obstacle. Hard to measure batteries in series...

I once invented a leapfrog matrix of current-limited SSRs to check a
series string of batteries. Odd/even nodes are switched to opposite
sides of a floating, bipolar ADC.

A couple more SSRs could make a flying-capacitor isolator.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On Tuesday, July 21, 2020 at 11:25:57 AM UTC-4, upsid...@downunder.com wrote:
On Tue, 21 Jul 2020 00:42:29 +0000 (UTC), David Lesher
wb8foz@panix.com> wrote:

boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?


Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....

Common grounds are another obstacle. Hard to measure batteries in series...

Power each measuring unit locally from local battery and connect the
units in series into a single current loop using optoisolators. If
more or less standard UARTs are used, use two current loops. Connect a
scheduler transmitter to one loop and use it to address individual
measuring units (with Rx pins connected to the loop with
optoisolator). The addressed unit then sends measurement data by
interrupting the current flow in the other loop. A central monitor
then extract the data from that loop.

The drawback is that every unit must drive the Tx into Mark (20 mA)
Idle state to allow current pass from one station to the next. These
days with better optoisolators a much smaller loop current (say 2 mA)
could be used.

To get rid of the polling circuit, some CAN (Controller Area Network)
style current loop could be used (e.g. 2 mA recessive state and 0 V
dominant state) and let the nodes themselves handle the arbitration on
the same loop with both Tx and Rx isolators in the same loop for all
stations.

You seem to be reinventing the telegraph. lol

No need for two loops unless you want redundancy.

--

Rick C.

+ Get 1,000 miles of free Supercharging
+ Tesla referral code - https://ts.la/richard11209
 
On Tuesday, July 21, 2020 at 11:25:57 AM UTC-4, upsid...@downunder.com wrote:
On Tue, 21 Jul 2020 00:42:29 +0000 (UTC), David Lesher
wb8foz@panix.com> wrote:

boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?


Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....

Common grounds are another obstacle. Hard to measure batteries in series...

Power each measuring unit locally from local battery and connect the
units in series into a single current loop using optoisolators. If
more or less standard UARTs are used, use two current loops. Connect a
scheduler transmitter to one loop and use it to address individual
measuring units (with Rx pins connected to the loop with
optoisolator). The addressed unit then sends measurement data by
interrupting the current flow in the other loop. A central monitor
then extract the data from that loop.

The drawback is that every unit must drive the Tx into Mark (20 mA)
Idle state to allow current pass from one station to the next. These
days with better optoisolators a much smaller loop current (say 2 mA)
could be used.

To get rid of the polling circuit, some CAN (Controller Area Network)
style current loop could be used (e.g. 2 mA recessive state and 0 V
dominant state) and let the nodes themselves handle the arbitration on
the same loop with both Tx and Rx isolators in the same loop for all
stations.

You seem to be reinventing the telegraph. lol

No need for two loops unless you want redundancy.

--

Rick C.

+ Get 1,000 miles of free Supercharging
+ Tesla referral code - https://ts.la/richard11209
 
On Tuesday, July 21, 2020 at 11:25:57 AM UTC-4, upsid...@downunder.com wrote:
On Tue, 21 Jul 2020 00:42:29 +0000 (UTC), David Lesher
wb8foz@panix.com> wrote:

boB <boB@K7IQ.com> writes:

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?


Not sure why there aren\'t any around ?

But we/I made our own for a battery shunt, in the negative lead A/D
monitor. Single wire is the power and two way data but only about 10
conversions per second in this case. The shunt is the second wire.

Used a 35 cent micro and I2C A/D. I don\'t see why you couldn\'t
address more than one of these on a single wire.

I suppose it all depends on how fast you need the data to be

Every few minutes will do.....

Common grounds are another obstacle. Hard to measure batteries in series...

Power each measuring unit locally from local battery and connect the
units in series into a single current loop using optoisolators. If
more or less standard UARTs are used, use two current loops. Connect a
scheduler transmitter to one loop and use it to address individual
measuring units (with Rx pins connected to the loop with
optoisolator). The addressed unit then sends measurement data by
interrupting the current flow in the other loop. A central monitor
then extract the data from that loop.

The drawback is that every unit must drive the Tx into Mark (20 mA)
Idle state to allow current pass from one station to the next. These
days with better optoisolators a much smaller loop current (say 2 mA)
could be used.

To get rid of the polling circuit, some CAN (Controller Area Network)
style current loop could be used (e.g. 2 mA recessive state and 0 V
dominant state) and let the nodes themselves handle the arbitration on
the same loop with both Tx and Rx isolators in the same loop for all
stations.

You seem to be reinventing the telegraph. lol

No need for two loops unless you want redundancy.

--

Rick C.

+ Get 1,000 miles of free Supercharging
+ Tesla referral code - https://ts.la/richard11209
 
On Monday, July 20, 2020 at 2:22:16 PM UTC-4, David Lesher wrote:
Was looking for a way to monitor a number of 12V deep cycle L-A batteries.
Since we have an installed 1-Wire network, it would be nice if we could
just add on to that.

But I notice a dearth of 1-Wire ADC\'s.
Any idea why?

Any digital device can be a 1-wire device. I would just program up a cheap MCU with a built in ADC to be controlled over 1-wire. It just takes a resistor and a cap to power it. No?

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
 

Welcome to EDABoard.com

Sponsor

Back
Top