Technical equipment of TC600 PLC
79
TXV 138 08.02
10.5.10 Incremental Encoder Servicing
Declaration of admeasuring is performed by the directive
#unit
with
general structure according to item 10.5.2.
#unit 0, 0, IRC_600, Xn, Yn, On
Parameter
TYP, POC_IN, POC_OUT
of directive
#unit
is input symboli-
cally as
IRC_600
or numerically
$40, 5, 9.
Placement of the state and
control word (parameters
Xn, Yn
) depends on the BM type (on occupation
of the scratchpad by images of inputs and outputs).
Admeasuring occupies the total of 14 bytes in the PLC scratchpad mem-
ory, 5 bytes in the image of inputs and 9 bytes in the image of outputs.
In the image inputs, the STAT state word is stored and the actual state of
the admeasured value. If interrupt is allowed, image of inputs is updated
before the start of the P44 process, or in the cycle loop if interrupt is prohib-
ited. Zone with the initial address defined by the parameter
Z_IN
of directive
#unit
has the following structure:
STAT
.7
STAT
.6
STAT
.5
STAT
.4
STAT
.3
STAT
.2
STAT
.1
STAT
.0
Z_IN
Least significant byte of the admeasured value
Z_IN+1
Z_IN+2
Z_IN+3
Most significant byte of the admeasured value
Z_IN+4
STAT.0 = 1 - overflow of the maximum admeasurement range in this cy-
cle (values 7FFF FFFFh)
STAT.1 = 1 - underflow of the minimum admeasurement range in this cy-
cle (values 8000 0000h)
STAT.2 = 1 - reaching of pre-selection for the ascending direction in this
cycle
STAT.3 = 1 - reaching of pre-selection for the descending direction in this
cycle
STAT.4
- immediate movement direction
0 = ascending (from lower values to the higher ones)
1 = descending (from higher values to the lower ones)
STAT.5
- flag of the mode of the reference point look up
0 = passive mode
1 = active mode
STAT.6
- reaching of pre-selection for the ascending direction
0 = admeasured value below pre-selection
1 = admeasured value above pre-selection
The bit is set to zero at overflow of the maximum admeas-
urement range.
STAT.7 =
- reaching of pre-selection for the descending direction
0 = admeasured value above pre-selection
1 = admeasured value below pre-selection
The bit is set to zero at underflow of the minimum admeas-
urement range.
Admeasurement registers every edge of the phase-shifted incremental
encoder signals, that means that the admeasured value is the quadruple
of the number of pulses of the generated incremental encoder's. For
example, in one incremental encoder loop with division into 1250 scale divi-
sions, addition of the admeasured value is 5000.
Declaration of
admeasuring
Declaration example
Servicing of
admeasurement
Image of inputs
The state word
The admeasured
value
