The time reference is provided by a 66 MHz counter. It is config-
ured using the
function. A period of 15.15 ns fol-
lows from this, and is defined as the smallest unit of time. It is re-
ferred to below as "1 tick". The resolution for T and t
1P
is therefore
1 tick (see also the specifications on page 38).
Note that the value of the maximum period T
max
. depends on the
duty cycle. A distinction is drawn between rectangular signals with
an asymmetrical duty cycle T
max. asym
. and a symmetrical duty cycle
T
max. sym
.
The figures for the ME-5810 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 21.
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 300 kHz. The resolution is 1 tick
= 15.15 ns. The measurement always starts at a rising edge. On
the ME-5810, all 4 frequency measuring channels (FI_A0…3) are
addressed as subdevices of type ME_TYPE_FI, subtype ME_SUB-
TYPE_SINGLE. Each channel can be programmed independently.
In combination with the plug-on board ME-5002, 4 additional fre-
quency measurement channels (FI_C0…3) are available which can
be addressed as one subdevice.
Note: If the frequency and duty cycle are the magnitudes you want,
these can easily be calculated from the values returned for
<pdTime>.
The formula is:
Frequency [Hz] = 1/period [s]
Duty cycle [%
] =
(„duration of the first phase of the period“[s]/ pe-
riod [s] x 100
4.1.2.2 Pulse Generator
In the pulse generator operating mode (FO = "Frequency Output")
you can output rectangular signals with a variable duty cycle at fre-
quencies of up to 3 kHz and with a resolution of 1 tick. On the ME-
5810, all 4 pulse generator channels (FO_B0…3) are addressed as
subdevices of type ME_TYPE_FO, subtype ME_SUBTYPE_SINGLE.
Each channel can be programmed independently.
