Chapter 5 Relay Ladder Logic Programming
67
-
Auxiliary Coils ( M )
Auxiliary Coils are the virtual coils inside the SG2 unit; they are not the real physically inputs or outputs that
can be wired to any external devices, switches, sensors, etc. The number of Auxiliary Relays M is 63. Since auxiliary
relays are internal elements within the CPU, they can be programmed as digital inputs (contacts) or digital outputs
(coils). In the first rung of this example, auxiliary relay M01 is being used as an output coil and will energize when
input I02 turns on. In the second rung auxiliary relay M01 is being used as an input and when energized, will turn on
outputs Q02 and Q03.
※
The state of auxiliary relays “M01~M3F” will be kept when the smart powers down if “M Keep” is active. “M
Keep” can be set by the two ways below.
Special Auxiliary Relays: M31~M3F
Code Signification
Description
M31
User program upstart flag Outputting ON during the first scanning period; and used as
normal auxiliary relay at other scan period.
M32
1second blinking output
0.5s ON, 0.5s OFF
M33
Summer/Winter output
Summer time turn ON, winter time turn OFF, used as normal
auxiliary relay.
M34
AT01 flag
Output ON when the first channel of SG2-4PT is error
M35
AT02 flag
Output ON when the second channel of SG2-4PT is error
M36
AT03 flag
Output ON when the third channel of SG2-4PT is error
M37
AT04 flag
Output ON when the fourth channel of SG2-4PT is error
M38
RS485 received flag
Output ON when the RS485 port has received data.
M39
RS232 received flag
Output ON when the RS232 port has received data.
M3A~M3C Reserved
M3D Received
flag
M3E Error
flag
M3F
Time out flag
MODBUS function using
(MU instruction)
PDF compression, OCR, web optimization using a watermarked evaluation copy of CVISION PDFCompressor