Manual ME-5001
Rev. 1.1E
Meilhaus Electronic
Page 25
Programming
Diagram 8: Signal definition
The time reference is provided by a 66 MHz counter. It is configured
using the
meIOSingleConfig()
function. A period of 15.15ns 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
specifications on page 29).
Note
that the value of the maximum period T
max.
depends on the duty
cycle. A distinction is drawn between rectangular signals with an asym-
metrical duty cycle T
max. asym.
and a symmetrical duty cycle T
max. sym.
.
The figures for the ME-5001 are:
T
max. asym.
= 32.5 s (0.03 Hz); T
max. sym.
= 65 s (0.015 Hz)
The wiring of the frequency inputs/outputs can be found in chapter 3.4
on page 18.
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
rectangular signals up to about 5.5 MHz. The resolution is 1 tick =
15.15 ns. The measurement always starts at a rising edge. On the
ME-5001, all 8 frequency measuring channels (FI_0…7) are addressed
as subdevices of type ME_TYPE_FI, subtype ME_SUBTYPE_
SINGLE. Each channel can be programmed independently.
0
High
T
max. asym
= ½ T
max. sym
Low
50%
100%
Period
(ME_IO_SINGLE_TYPE_FIO_TICKS_TOTAL)
Pulse duration of the first phase of the period
(ME_IO_SINGLE_TYPE_FIO_TICKS_FIRST_PHASE)
„First phase“
T
t
1P
sym.
asym.
