Siemens S7 300 CPU Status and LED Errors Explanation

In Siemens S7 300 CPUs, there is a series of LED lights with different colors which shows us the modes, status, and errors of the PLC.

S7 300 LED Errors

System fault: it indicates there is an error in the system, this error could be software error like an error in programming or hardware error like a power loss of one of the input modules

Color: Steady Red

Bus Fault: it indicates that there is an error in the system network, like a bad contact in one of the communication connectors, or there is an overlap between the addresses in the network

Color: Steady Red

MAINT

Maintenance: where ever this indicator energized this means that the CPU is not working anymore and needs a service, but this is rarely happening.

Color: Steady yellow

DC5V

This led indicates that there is a 24 Volt DC provided to the CPU.

Color: Steady Green

FRCE

Force: it indicates that at least one of the PLC inputs or outputs is forced to on or off.

Color: Steady yellow

Run

Run mode is on whenever the CPU is working properly without any troubles, and flashes in the startup of the CPU.

Color: Steady Green

STOP

When the CPU is in STOP mode or there is a software/hardware error.

Color: Steady yellow

For a memory reset request when inserting the memory card.

Color: Yellow flashes slowly

When the memory reset is being carried out.

Color: Yellow flashes quickly

END

Comments

Ferrules and Cross Ferruling

Ferrules are identification labels provided for every wire terminations in an instrument, equipment, or electrical/instrumentation control panels. These tube-shaped sleeves can be inserted easily on each individual wire in a multi-core cable. In earlier days fixed digits/letters are used as ferrules, but now Instrumentation engineers/technicians prints out desired ferrules by using a ferrule printing machine. Typical Ferrule The numbers/ letters on the ferrules will be given as per the approved electrical hook up or loop diagrams. This helps technicians to easily identify a particular loop/wiring from a series of terminal blocks and to troubleshoot the desired terminal connection. Separate numbers on the ferrules distinguish the positive and negative polarities of wires, thus ensure the polarity protection of the instrument. Cross Ferruling As a wire is connected on its both ends, it is quite useful to use a cross reference method for wire identification. Unlike normal ferru...

PLC Program for Mixing Tank

Create a ladder diagram for controlling a batch mixing process. Implement a PLC program for mixing tank or Mixing Process using PLC Ladder Logic. PLC Program for Mixing Tank Fig : Mixing tank A tank is used to mix two liquids. The required control circuit operates as follows: A. When the START button is pressed, solenoids A and B energize. This permits the two liquids to begin ﬁlling the tank. B. When the tank is ﬁlled, the ﬂoat switch trips. This de-energizes solenoids A and B and starts the motor used to mix the liquids together. C. The motor is permitted to run for 1 minute. After 1 minute has elapsed, the motor turns off and solenoid C energizes to drain the tank. D. When the tank is empty, the ﬂoat switch de- energizes solenoid C. E. A STOP button can be used to stop the process at any point. F. If the motor becomes overloaded, the action of the entire circuit will stop. G. Once the circuit has been energized, it will continue to operate until it is manually stopped. Solution...

What is a Torbar? – Averaging Pitot Tubes

The Torbar is employed for flow measurement of liquids, gases, or steam in circular, square, or rectangular section ducts for large flow rates. The Torbar is an insertion type multi-port self-averaging primary sensor for flow measurement. Torbar TORBAR is a set of Pitot tubes mounted on a bar across the pipeline with no moving parts. An averaging Pitot tube is a technology, while TORBAR is a manufacturing brand name. There are several brands available in the market with VERABAR, ANNUBAR, etc. Averaging Pitot Tube Principle Purpose Averaging Pitot tube can be employed when the average velocity of the flow profile, rather than the velocity in a specific point in the cross-section is desired. Averaging Pitot Tubes Principle It measures the differential pressure between the static pressure tap and the tap of full pressure of a stream. Thus such magnitude of differential pressure is directly proportional to the square of the flow rate. Working The TORBAR is designed in such a way that ...

TILI Automation

Search This Blog