OMRON K-type PLC Maintenance Guide

The TR area provides 8 bits from TR0 to TR7 for temporarily storing execution conditions at the branch points of the ladder diagram. Only used in conjunction with LD and OUT instructions, the same TR bit cannot be reused for OUT in the same instruction block, but can be used multiple times for LD.

2.7 Program Memory (UM)

UM has a capacity of 1194 words and stores user programs. The program starts at address 0000 and ends with the END (01) instruction. Each instruction occupies 1-4 words.

Chapter 3: Fundamentals of Ladder Diagram Programming

3.1 Basic Instructions

The ladder diagram consists of a left bus, a condition (normally open/normally closed), and a right output command.

Command symbol function

LD normally open contact starts the logic block in the state of pointing position

LD NOT normally closed contact starts the logic block with the reverse state of the pointing position

AND concatenates normally open and current execution condition logic and

AND NOT concatenates normally closed and current execution condition logic with non

OR parallel normally open and current execution condition logic or

OR NOT parallel normally closed and current execution condition logic OR NOT

OUT coil outputs the execution condition to the designated location

OUT NOT inverting coil will execute condition inversion and output

END (01) The program ends and must be placed at the end

3.2 Logical Block Instructions (AND LD/OR LD)

When there are complex series parallel combinations in a ladder diagram, the circuit needs to be decomposed into logic blocks and then combined with AND LD (series block) or OR LD (parallel block). For example, when two parallel branches are connected in series, start each branch separately with LD, and then combine them with AND LD. When programming, you can choose to combine the first two blocks first and then combine the subsequent blocks one by one, or list all blocks first and then combine them in reverse order using AND LD (up to 8 blocks).

3.3 Branches and Temporary Storage (TR Bit)

When there is still a serial condition in the first branch after the branch point of the ladder diagram, the execution condition after the branch point may be lost, and TR bits need to be temporarily stored. Method: Use OUT TR0 to save execution conditions at branch points, and then use LD TR0 to restore them at each branch. If there is no serial condition after the branch point (direct output), there is no need for TR bit.

3.4 Interlocking (IL/ILC) and Jumping (JMP/JME)

Interlock (IL (02)/ILC (03)): When the IL execution condition is OFF, the OUT bit between IL and ILC is forcibly OFF, the timer is reset, the counter is held, and other instructions are not executed. Suitable for situations where safe shutdown of output is required.

Jump (JMP (04)/JME (05)): Jump numbers 01~08 can only be used once. When the JMP condition is OFF, all intermediate instructions are skipped without changing any state. The jump number 00 can be used multiple times to jump to the next JME (00). Jump is suitable for situations where output status needs to be maintained (such as hydraulic and pneumatic equipment).

Chapter 4: Programmer Operation - Essential for On site Debugging

The most commonly used programming device for K-type PLCs is the Programming Console, which comes in vertical models (3G2A5-PRO13-E) and handheld models (C200H-PRO27-E).

4.1 Enter programming mode

After power on, the programmer displays "Password!". Press CLR, then press MONTR, and then press CLR to clear the display and enter. The mode switches include:

Program: Program input/modification/clearing, do not execute the program

MONITOR: Program runs to monitor and modify data

RUN: Normal execution, can only monitor

4.2 Clear Memory

Clear memory before new programming: Press CLR → Press SHIFT+CLR (MONTR display) → Press RESET (display "0000MEM CLR?") → Press MONTR. HR, TC, and DM areas can also be selectively retained.

4.3 Input Program

Taking "LD 0000" as an example:

Clear display by CLR

Enter the address (e.g. 0000) and press the down arrow key

Press the LD key, then press 0, 0, 0, 0

Press Write

Continue to input the next instruction

For function code commands (such as TIMH (15)): press FUN, enter 15, press WRITE, then enter TC number, press WRITE, enter SV, press WRITE.

4.4 Inspection Procedure

Press CLR → SRCH → SRCH, and the program will automatically check for syntax errors. If an error is found, it will stop and display an error code, press SRCH to continue. Common errors:

NO END INST: Missing END instruction

CIRCUIT ERR: Number of logical blocks does not match

COIL DUPL: The same output bit is controlled by multiple instructions

IL ILC ERR: IL/ILC mismatch

4.5 Surveillance and Enforcement

Bit/word monitoring: Enter the address to be monitored and press MONTR. Up to 6 addresses can be monitored simultaneously (3 displayed). In MONITOR/RUN mode, ON/OFF status will be displayed.

Force Set/Reset: In monitoring mode, press PLAY/SET to force ON and REC/RESET to force OFF (for only one scan cycle).

Modify PV/SV: While in monitoring mode, press CHG, enter the new value, and press WRITE.

4.6 Tape Drive Backup