Automation Direct D0-DCM, Руководство пользователя

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Getting Started
User Application
Guidelines
RLL
Programming
for Communications
4–16
RLL Programming for Communications
DL05/06 Data Communications Module, 1st Edition, 08/05
The Shift Register can be used for creating interlocks, as an alternative to using
control relays. For a complete explanation of the function of the Shift Register, see
the User Manual for your PLC. If you have more than a few RX/WX instructions,
using control relays can become cumbersome. The Shift Register allows a single
contact to be used in each communication rung as an interlock.
SR
SP1
The data input to the Shift Register
(SR) is Special Relay SP1. SP1 is the
always-on bit. Combined with a
normally closed contact it sends zeros
to the Shift Register data input.
The clock input to the Shift Register is
SP122, the communication busy bit.
Each time one of the RX/WX
instructions executes, the Shift
Register moves the set bit over one
place.
C63 is used in this example to reset the
Shift Register to all zeros.
C60
C77
SP122
C63
Shift Register after first RX/WX.
C74 C73 C72 C71 C70 C67 C66 C65 C64 C63 C62 C61 C60 C75 C76 C77
Shift Register after first scan.
C74 C73 C72 C71 C70 C67 C66 C65 C64 C63 C62 C61 C60 C75 C76 C77
C74 C73 C72 C71 C70 C67 C66 C65 C64 C63 C62 C61 C60 C75 C76 C77
C74 C73 C72 C71 C70 C67 C66 C65 C64 C63 C62 C61 C60 C75 C76 C77
C74 C73 C72 C71 C70 C67 C66 C65 C64 C63 C62 C61 C60 C75 C76 C77
Shift Register after second RX/WX.
Shift Register after second scan.
C74 C73 C72 C71 C70 C67 C66 C65 C64 C63 C62 C61 C60 C75 C76 C77
Shift Register after third RX/WX.
Shift Register after third RX/WX plus one scan.
V40603
The Store If Equal instruction detects
when the Shift Register is reset to
zeros. When that condition is true the
C60 bit is SET by this rung. The C60 bit
becomes the high bit shifted by the
Shift Register until each RX/WX
instruction is executed in turn.
SET
=
K0
C60
Shift Register
Store If Equal