Delta Electronics Programmable Logic Controller DVP-PLC - Manual (Page 10)

1 Basic Principles of PLC Ladder Diagram
DVP-PLC Application Manual 1-6
File register
The file register is used for storing the data or all kinds of parameters when the data registers
required for processing the data and value operations are insufficient. Every file register is able
to store a 16-bit word. Double words will occupy 2 adjacent file registers. In SA/SX/SC series
MPU, there are 1,600 file registers. In EH/EH2/SV series MPU, there are 10,000 file registers.
There is not an actual device No. for a file register. The reading and writing of file registers
should be executed by instructions API 148 MEMR, API 149 MEMW, or through the peripheral
device HPP02 and WPLSoft.
& Device indication: K0 ~ K9,999, numbered in decimal form.
Index register
E and F index registers are 16-bit data registers as other data registers. They can be read and
written and can be used in word devices, bit devices or as a constant for index indication.
& Device indication: E0 ~ E7, F0 ~ F7 are indicated as E and F and numbered in decimal
form.
The structure of a ladder diagram:
Structure Explanation Instruction Devices Used
Normally open, contact A LD X, Y, M, S, T, C
Normally closed, contact B LDI X, Y, M, S, T, C
Normally open in series
connection
AND X, Y, M, S, T, C
Normally closed in series
connection
ANI X, Y, M, S, T, C
Normally open in parallel
connection
OR X, Y, M, S, T, C
Normally closed in parallel
connection
ORI X, Y, M, S, T, C
Rising-edge trigger switch LDP X, Y, M, S, T, C
Falling-edge trigger switch LDF X, Y, M, S, T, C
Rising-edge trigger in series
connection
ANDP X, Y, M, S, T, C
Falling-edge trigger in series
connection
ANDF X, Y, M, S, T, C
Rising-edge trigger in parallel
connection
ORP X, Y, M, S, T, C
Falling-edge trigger in parallel
connection
ORF X, Y, M, S, T, C
Block in series connection ANB -
Block in parallel connection ORB -