Technical equipment of TC600 PLC
81
TXV 138 08.02
Admeasured
value
Zero IRC pulse
Pre-selection for the
descending direction
Pre-selection for the
descending direction
Fig.10.9 Time diagram of admeasuring using incremental encoder
10.5.11 Measurement of the Signal Period and Phase Shift
The function declaration is performed by the directive
#unit
with general
structure according to item 10.5.2.
#unit 0, 0, Period_600, Xn, X_On ;measurement of the TC600
;period and phase shift
Parameter
TYP, POC_IN, POC_OUT
of directive
#unit
is input symboli-
cally as
Period_600
or numerically
$50, 2, 0
.
Placement of the function output (parameter
Xn
) depends on the pro-
grammable controller type (occupation of the scratchpad by images of in-
puts and outputs).
Both measurement modes occupy in the image of inputs of the PLC
scratchpad memory 2 bytes at address defined by the parameter
Xn
of di-
rective
#unit
. A content of the image is updated in the user program cycle
loop.
In measurement of the signal period, these 2 bytes have the meaning of
the number of cycles of the internal clock signal per 1 period of the meas-
ured signal. In measurement of the phase shift, they have the meaning of
the number of cycles of the internal clock signal between two descending
edges of the measured signals.
Function declaration
Declaration example
Servicing of the
function
