170
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
7 Basic Instruction
7.5 LDP, LDF, ANDP, ANDF, ORP, ORF
5. Differences in the operation caused by auxiliary relay (M) numbers
When an auxiliary relay (M) is specified as a device in LDP, LDF, ANDP, ANDF, ORP and ORF instructions,
the operation varies depending on the device number range as shown in the figure below.
<M0 to M2799, M3072 to M7679>
After M0 is driven by X000, all contacts [1] to [4] corresponding
to M0 are activated.
•The contacts [1] to [3] detect the rising edge of M0.
•Because of LD instruction, the contact [4] is conductive
while M0 is ON.
<M2800 to M3071>
From M2800 driven by X000, the program is divided into the
upper block (block A) and the lower block (block B). In each of
the blocks A and B, only the first contact which detects the
rising or falling edge is activated.
Because of LD instruction, the contact in the block C is
conductive while M2800 is ON.
By utilizing these characteristics, "transition of state by same
signal" in a step ladder circuit can be efficiently programmed.
M0
[1]
M0
M51
X000
M0
SET
[2]
M0
[4]
M0
M52
SET
[3]
M50
SET
M53
Block B
M2800
X000
M2800
M1
SET
M0
SET
M2800
M2800
M3
SET
M2
SET
M2800
M2800
M5
SET
M4
SET
M2800
M2800
M6
SET
Block A
M7
M2800
Block C