Basics Of S7-400

• Above Picture is basically of CPU41x-1. In this one port X1 is present and accordingly LEDs are present. X1 port is of MPI/DP.Near to MPI/DP serial number of CPU is present which in further helps in getting manufacturing data.
• Mode selector switch is used to change CPU mode manually. We can make it either RUN/Stop/MRES.
•  LED indications help in determine the status of CPU, fault diagnosis at glance. Details diagnosis can be done through CPU Module information option available in PG step 7.
•  Memory card slot is used to insert memory card of two type:
  a.    FLASH card.
              b.   RAM card.
•  External Battery connector is used to supply voltage to CPU through external supply range from 5 V-15 V in case of change of power card. This is used to maintain the program in the RAM and also to maintain values at counter, timer etc. It requires 2.5 mm Jack and to check the polarity as shown below.

a

• It’s similar to CPU 41x-1 but it has basically three port so called CPU 41x-3. It has

a.    MPI/DP

b.    DP

c.    Extra slot.

• LED indications also increased which includes Bus1F, Bus2F and IFM1F. CPU 41x-4 also comes which has two extra slot.
• LED of CPU:

LED	COLOR	MEANING
INTF	Red	Internal Error
EXTF	Red	Hardware Error
Run	Green	CPU in run mode
Stop	Yellow	CPU in stop mode
BUS1F	Red	Bus error at MPI/DP
BUS2F	Red	Bus error at DP
IFM1F	Red	Error at Interface sub module 1
IFM2F	Red	Error at Interface sub module 2

•  Depending on CPU41x-y. LED indications are valid on y.

LED		MEANING
RUN	STOP
H	D	CPU is in run mode.
D	H	CPU is in stop mode. If went due to error then ExtF and IntF will also blink.
B 2 Hz	B 2 Hz	Its CPU hardware error, generally with this all other LED also flashes.
B 0.5 Hz	H	CPU hold was triggered by a test function.
B 2 Hz	H	A warm restart / cold restart / hot restart was triggered. It can take a minute or longer to execute these functions, based on the length of the OB called. If the CPU still does not go into RUN, there might be an error in the system configuration.
x	B 0.5 Hz	CPU request memory reset.
x	B 2 Hz	Memory Reset of CPU is active.

SERVICE DATA

Select the “PLC –> Save service data” menu command to read this information, then save the data to two files and send these to your Customer Support Center.

Please note:

You should save all service data immediately after the CPU has changed to STOP, or when a                redundant system has lost its synchronization.

        Always save the service data of both CPUs in the redundant system, that is, including the data of the CPU which is still in RUN after synchronization is lost.

The service data are written to the file <filename.ext> in the <pathname> path.

Multi-Computing

It basically refers to concurrent operation of several maximum 4 CPU. Participating CPU automatically changes their status in synchronism. That is, all CPUs are in synchronism during startup and transitions to STOP. Every CPU executes its own user program, irrespective of the user programs in the other CPUs. This feature facilitates the execution of control tasks in parallel. Some data can be share with each on same k bus.

  Rack UR1 and UR2 can generally be used. CR3 has four slots so only two CPU multi-computing can be used. Segment rack such as CR2 (10 +8) cannot be used as it allows only one CPU in a segment in software. Two CPU in different segment is not multi-computing as they work independent and not share logical address space.

In the following situations it is of advantage to use multi-computing:
The size of your user program exceeds the capacity of a single CPU and you run out of storage space: distribute program execution to several CPUs.
A certain part of your system requires high-speed processing: cut the relevant program section from the program and process it on a separate “high-speed” CPU.
Your system consists of several units which can be easily partitioned and controlled independently: Execute system partition 1 on CPU 1, system partition 2 on CPU 2, etc.