I have a number of 4-20ma devices interfaced through 1wire. I simply use a
quad channel DS2450 with a precision 250 ohm resistor across the inputs.
4-20ma across 250 ohm = 1-5 VDC
Its very simple with 4-20ma, I see no point in paying any more than a DS2450
and 4 resistors. well the 250 ohm is expensive ($15.00 each) so I have used 4
x 1k in parallel in the past. I must admit though each of my devices has an
isolated 4-20 mA current loop.
cheers
rob
----- Original Message -----
From: Paul Alfille
To: [email protected]
Sent: Tuesday, January 29, 2008 7:46 AM
Subject: Re: [Owfs-developers] Fwd: CMC industrial Electronics Ltd
1-wiremodule
On Jan 28, 2008 12:54 PM, Doug Collinge <[EMAIL PROTECTED]> wrote:
Wire® - 8 bit CRC. The family code for the sensor is 178 decimal or B2 Hex.
The sensor
0xB2 is an alias of 0x32 -- the DS2780 (see
http://owfs.org/index.php?page=standard-devices)
which should be supported.
According to the datasheet, or
http://owfs.org/index.php?page=voltage-measurement, the DS2780 is essentially a
0-5V chip, suggesting there is some conditioning circuitry in the device.
Paul Alfille
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