moeller easy plc and proxy freq connection
moeller easy plc and proxy freq connection
(OP)
I need to connect a proxy reading freq. between 2000 and 5000hz which is on a diesel loco engine fly wheel. all this does is it converted to rpm but I need to shut dowm the engine when it over revs.I have a moeller 512 rc dc plc.(12vdc unit)
will i need to convert the proxy signal to an 4-20 ma signal or a voltage signal?I have never done this before and need to know what to do and buy.Someone said i could use a high speed counter if the plc is fitted with it.How do i do this?
will i need to convert the proxy signal to an 4-20 ma signal or a voltage signal?I have never done this before and need to know what to do and buy.Someone said i could use a high speed counter if the plc is fitted with it.How do i do this?





RE: moeller easy plc and proxy freq connection
The speed of the engine is usually in the 2000 - 5000 RPM range and that means that your frequency is more likely to be in the 33 - 83 Hz range. There is a fair chance to count that low frequency in the PLC program itself. Some PLCs have count instructions that makes the task even simpler.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: moeller easy plc and proxy freq connection
Cheers Niallnz
RE: moeller easy plc and proxy freq connection
RE: moeller easy plc and proxy freq connection
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: moeller easy plc and proxy freq connection
RE: moeller easy plc and proxy freq connection
so how do you determine this above?
guide to go by in calculating this is
calculate the diameter of the flywheel
calculate circumference
calculate inches/pulse = circumference/dia
convert to your range of speeds you are testing for
then do a table on inches/milliseconds to MPH in same table
What is the known scan time? 10 milliseconds for example
calculate
inches/process scan = (inches/millisecond)*scantime
now compare this to your calculation on inches/pulse
inches/process scan < inches/pulse
if true then your plc will be able to handle that speed.
remember if you keep adding more stuff in your program this will change your scan time if the scan is continuous. Thats why people invented high speed counters, event driven scans, periodic scans, etc... as stated above