Requirement Of Power Sequence In Cpu Module & Expansion Module - FATEK M Series User Manual

Chapter 4 Power Wiring, Power Consumption Calculation, and Power Sequence Requirements
4-4 Requirement of Power Sequence in CPU Module & Expansion
Module
When the power is on, the M-Series PLC first detects the type and number of expansion module
attached to its expansion interface and get the actual I/O configuration. Therefore, while the CPU module
performs detection, the power in expansion module should be already UP, otherwise, the detected I/O
configuration will not correct. Namely, the power of expansion module should be ON simultaneously or
even earlier. There will be no time sequence error when CPU module/expansion module are connected
together to one power. If the expansion module and CPU module powered by different powers (or the
same power but different switches), or external power supply is used for expansion modules, time sequence
of both powers should be considered. To solve the problem of the expansion module power not get ready
before CPU module power does, M-Series PLC provides a special R35367 register which can delay the
detection time of I/O configuration. The time base of R35367 is 0.01sec with a default value of 0, which can
be set from 0~1000 (0~10sec), as shown in the figure below. If the expansion module power cannot be UP
within 1sec after main unit power is ON, the R35367 time needs to be set longer to delay the detection by
CPU. It cannot exceed 10sec, however, otherwise the configuration of expansion interface cannot be
detected.
Power Timing Diagram
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M-Series PLC Expansion Module User Manual