Converting 0-10 to 0-20mA
Converting 0-10 to 0-20mA
(OP)
Hi,
I need to convert a signal from 0-10V to 0-20mA.
Can somebody help please (schematic?)
Thanks in advance
Morcego
I need to convert a signal from 0-10V to 0-20mA.
Can somebody help please (schematic?)
Thanks in advance
Morcego





RE: Converting 0-10 to 0-20mA
TTFN
RE: Converting 0-10 to 0-20mA
A 500 ohm resistor used with 10V equals 20mA but doesn't take into account what you are driving. What it's compliance voltage is, etc.
It is much simpler to convert 0-20mA to 0-10V than what you want.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Converting 0-10 to 0-20mA
http:/
Quote: "Inputs accepted from most electrical sources, e.g. d.c. mV, V, mA, thermocouples, RTDs, resistance, potentiometers, strain gauges, frequency, a.c. voltage, a.c. current.
Outputs – the common d.c. mA, V ranges, and volt-free relay contacts are available"
Gunnar Englund
www.gke.org
RE: Converting 0-10 to 0-20mA
My first choice would be to check if the existing equipment can be reconfigured.
My second choice would be skogsgurra's suggestion.
My third choice would be a resistor to bring the total loop resistance to 500 ohms.
To say that the resistor nis the third choice is not to belittle it. There are circumstances where I would happily use the resistor.
respectfully
RE: Converting 0-10 to 0-20mA
Gunnar Englund
www.gke.org
RE: Converting 0-10 to 0-20mA
I've used both. I have serviced panels with 10 V components, but but I have never had to modify them.
Respectfully
RE: Converting 0-10 to 0-20mA
Wath I need is a driver. I want to use a microcontroller and a A/D converter to generate the output voltage. No problems here. My costumer wants also 0-20 mA output. I has thinking in use the voltage of the D/A to generate the current. The costumer wants a standard current loop device from 0-20mA.
Thanks
RE: Converting 0-10 to 0-20mA
There is a collection of design ideas on this address: http://www.discovercircuits.com/C/cur-loop.htm
You may need to think about galvanic isolation. Most customers expect that from their current loops.
Gunnar Englund
www.gke.org
RE: Converting 0-10 to 0-20mA
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Converting 0-10 to 0-20mA
I have designed stuff that probably is very close to what you want.
Assuming that what you have is a microprocessor, and you are already thinking of using a D/A converter (you wrote A/D, but I know you meant D/A), then you should look up the Analog Devices AD420.
It conects to the uP via an SPI interface, and includes internally: A/D converter, reference, voltage regulator, current driver. Handles loop compliance voltages up to 24V. It can be configured for 0-20 mA, 4-20 mA, and 0-24 mA.
Resolution is 16 bits, but that is very hard to achieve in any normal noisy digital environment. 12 bits is not too hard.
It can also do voltage output, or just stick a precision resistor in the loop.
Have fun.
Philip Freidin
RE: Converting 0-10 to 0-20mA
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Converting 0-10 to 0-20mA
http:/