A
amorphia
- Jan 1, 1970
- 0
Hi all,
I hoped someone might be able to give me some advice about how to
interface a pressure meter I have borrowed. It is a Hopkins Innovex
600D, I can't find a data sheet, but I don't think that matters as it
must operate according to some simple principles which someone here
will probably be able to tell me. It just has three wires, for output,
supply, and ground. The ratings written on it are: supply 12V, range
0-2 inches WC, and output 4-20 MA.
The bit I don't understand is this - when I have dealt with similar
sensors before, the output has been a voltage range, but I guess that
in this case MA means milliamps, i.e. a current. I connected 12V
across the ground and supply, and put my voltmeter across the ground
and the output. When I change the pressure a lot, the voltage only
changed between 6.13 and 6.15. That seems very insensitive, and given
that the output is given in current not volts, I wonder if I should be
using some other method to measure the output, i.e. one that lets
current flow, seeing as it output is given as a current. But I'm not
sure how.
If anyone can give me some advice I would very much appreciate it!
Cheers,
Ben
I hoped someone might be able to give me some advice about how to
interface a pressure meter I have borrowed. It is a Hopkins Innovex
600D, I can't find a data sheet, but I don't think that matters as it
must operate according to some simple principles which someone here
will probably be able to tell me. It just has three wires, for output,
supply, and ground. The ratings written on it are: supply 12V, range
0-2 inches WC, and output 4-20 MA.
The bit I don't understand is this - when I have dealt with similar
sensors before, the output has been a voltage range, but I guess that
in this case MA means milliamps, i.e. a current. I connected 12V
across the ground and supply, and put my voltmeter across the ground
and the output. When I change the pressure a lot, the voltage only
changed between 6.13 and 6.15. That seems very insensitive, and given
that the output is given in current not volts, I wonder if I should be
using some other method to measure the output, i.e. one that lets
current flow, seeing as it output is given as a current. But I'm not
sure how.
If anyone can give me some advice I would very much appreciate it!
Cheers,
Ben