How to hook up a Frequency Counter

[kayvee]

Hey everyone!

I have this machine that *should* be switching on and off at a
frequency of about 110-120HZ. It is powered by a 24DC power supply and
is controlled by a 12.5W, 100Ohm Rheostat placed in series with the
machine. It usually draws about 0.2A ~ 0.4A (fused at 0.5A).

As of now I have no way of telling what the frequency of the machine
(it is very important that it is accurate), and I plan on buying a
panel mounted frequency counter to rectify this problem... But looking
at the stats of the frequency counters I can afford out there they
don't like being given any more than 10-40mA.

Now the question is how do I hook up this frequency counter to measure
my machine without hooking it in a fashion which would give it the
full brutality of the current?

Once again, any input would be greatly appreciated and thanks again!

 

[John Fields]

On Mon, 22 Sep 2008 19:12:54 -0700 (PDT), kayvee <kmvgroups@gmail.com>
wrote:

Hey everyone!

I have this machine that *should* be switching on and off at a
frequency of about 110-120HZ. It is powered by a 24DC power supply and
is controlled by a 12.5W, 100Ohm Rheostat placed in series with the
machine. It usually draws about 0.2A ~ 0.4A (fused at 0.5A).

As of now I have no way of telling what the frequency of the machine
(it is very important that it is accurate), and I plan on buying a
panel mounted frequency counter to rectify this problem... But looking
at the stats of the frequency counters I can afford out there they
don't like being given any more than 10-40mA.

Now the question is how do I hook up this frequency counter to measure
my machine without hooking it in a fashion which would give it the
full brutality of the current?

---
If the counter is rated to draw 10-40mA at a particular supply voltage,
then, regardless of what the supply can deliver, that's what it'll use
and you needn't concern yourself with the "full brutality of the
current".

Your hookup will look something like this: (View in Courier)


+24V>-----+-----------[REGULATOR]-------+
| | |
[RHEOSTAT] | |
| | |
[YOUR MACHINE]---------|------->[COUNTER]
| | |
GND>------+----------------+------------+

If you can tell us more about the counter and the machine (Specifically,
what the counter wants to see in terms of supply and signal input
voltage and current, and what your machine can supply as a signal input
to the counter) we can supply you with more details re. the hookup.

JF