Datexel DAT 6000 SERIES, Руководство пользователя

Страница: 16 / 20

DAT 6000
16
PRELIMINARY
EXAMPLE n°1 : 2 or 4 channels reading
The procedure is fast and with few instructions because there are not
synchronism controls. However, if the synchronism is lost (i.e. for a noise), the
reading will be wrong. To avoid that, it is advisable to use the ENABLE signal to
synchronize the procedure at the reading start.
The following two examples, each one toghether with its flow-graph, illustrate
the procedure to be followed for writing the PLC’s instructions.
START
ENABLE HIGH
DELAY
n = n - 1 n = 0 ?
READ BIT
REGISTER [n] = y
CHANNAEL (a) =
REGISTER
n = 15
a = a + 1
a = 2 ?
(NOTE 1)
DELAY
CLK LOW
DELAY
CLK HIGH
y = DATA
READ BIT
a = 0
end of channels reading
YES
NO
YES NO
read next channel
end of channel reading
read next bit
read input bit
READ BIT
The first bit is the
most significant
ENABLE LOW
DELAY
NOTE 1 : to be modified following the number of channels to be read ( write " a = 4 ? " for the 4 channels reading )
NOTE 2 : follow the (A) option to reset the device or for not reading the unused channels
A
NOTE 2
Definitions:
ENABLE, CLK and DATA = interface signals
SYNC = synchronism bit
REGISTER = data reading buffer
n = a bit of REGISTER buffer (0..15)
CHANNEL = digital channel measurement value
a = channel number (1,2,3 or 4)
x, y = bits
DELAY = delay function (ms). The delay time must be
higher than the setting of the digital filter