Manual ME-582x Series
Revision 0.9
4 Programming
page 24
Meilhaus Electronic
Please read the ME-iDS manual and the ME-iDS help file (*.chm) care-
fully prior to programming.
You can open both of these documents
through the "ME-iDS Control Center" or through the Windows Start menu.
Two variables are introduced to describe the rectangular signal, and apply
equally to input and output. One value indicates the period T, while the
other value provides the duration of the pulse of the first phase of the pe-
riod t
1P
. For frequency measurement, the measurement starts with the first
rising edge, and finishes with the next rising edge. The falling edge that
lies between them defines the end of the first phase. In pulse generator
mode, output normally starts with a high level, changing to the low level
when the first phase has elapsed.
Picture 133: Signal definition
The time reference is provided by a 66 MHz counter. It is configured using
the
meIOSingleConfig()
function. A period of 15.15 ns follows from this,
and is defined as the smallest unit of time. It is referred to below as "1
tick". The resolution for T and t
1P
is therefore 1 tick (see also the specifica-
tions on page 29).
Note
that the value of the maximum period T
max
. depends on the duty cy-
cle. A distinction is drawn between rectangular signals with an asymmet-
rical duty cycle T
max. asym
. and a symmetrical duty cycle T
max. sym
.
The figures for the ME-5820 series are:
T
max. asym.
= 16.25
s (0.06
Hz); T
max. sym.
= 32.5
s (0.03
Hz)
The wiring of the frequency inputs/outputs can be found in chapter 3.6 on
page 16.
4.1.2.1
Frequency Measurement
With the frequency measurement operating mode (FI= "Frequency In-put")
you can determine the period or frequency, and the duty cycle of rectangu-
lar signals up to 300 kHz. The resolution is 1 tick = 15.15 ns. The meas-
urement always starts at a rising edge. On the ME-5820, all 4 frequency
measuring c
hannels (FI_A0…3) are addressed as subdevices of type
