LS K7M-DR14UE Economical PLC

LS ELECTRIC (formerly LG Industrial Systems), K120SE series economical CPU module, end-of-life, only stock & second-hand spare parts available on the market.

✅ Model Definition

K7M: MASTER-K120S CPU series

DR: D = DC24V Input, R = Relay Output

14: Total I/O points =14 (8 Inputs + 6 Outputs)

UE: K120SE economical version (Compare with standard U series, program memory: 2K steps)

📋 Core Specifications

🧩 Typical Application Scenarios

Small standalone machine control: conveyors, small presses, packaging machines, simple HVAC, flameproof mining switches, control cabinet accessories. Suitable for digital logic plus limited high-speed counting.

Relay output cannot generate pulse for positioning (DT/DRT transistor model required for positioning)

⚠️ Important Notes

1. Relay output limitation: Mechanical contact, not suitable for frequent on/off operations; max ~1200 switching cycles/hour, frequent operation accelerates contact burnout.
2. Discontinued model: Not recommended for new projects. For replacement maintenance, verify program capacity first (UE=2K steps, standard DR14U=7K; program exceeding 2K cannot be downloaded directly).
3. Communication: RS485 uses LS proprietary Cnet protocol, compatible with SCADA & touchscreen.
4. Built-in DC24V sensor supply: The PLC provides 24VDC for sensors, limited capacity.

📌 K120SE Series Lineup

K7M-DR10UE: 6DI+4DO

K7M-DR14UE: 8DI+6DO

K7M-DR20UE:12DI+8DO

K7M-DR30UE:18DI+12DO

🔁 Alternative Selection

Domestic replacement: Inovance H1U-0806MR, Xinje XC2-08R-E;

LS upgraded platform: XBC series (XBC-DR14E)

🛠 Common Troubleshooting

1. PWR lamp off: AC power supply, blown internal 2A time-delay fuse
2. RUN lamp off: program error, STOP mode via switch/host PC, watchdog overflow
3. No output action: aged/burned relay contact (common on second-hand units), broken COM wiring
4. Communication failure: RS232/485 wiring polarity, station number, baud rate, terminating resistor

Programming Software for LS K7M-DR14UE (MASTER-K120S)

✅ Official programming software: KGLWIN

XG5000 mentioned before is for XGB/XGT series, not compatible with K120S K7M, do not install the wrong software.

Version Info

Common stable release: KGLWIN 3.62, also 3.5, 3.7 available. Originally designed for Win98/XP. Win10/Win11 requires compatibility mode.

Languages: Ladder LD, Instruction List IL

Functions: Program edit, online monitor, I/O force, upload/download, comment, fault diagnosis

Handheld programmer: KLD-150S (old portable unit for field commissioning)

Online Connection Method

Built-in RS232C programming port on PLC:

1. Legacy: PC DB9 serial direct cable
2. Modern PCs without native serial port: USB to RS232 adapter (CH340/PL2303 chip), select corresponding COM port inside KGLWIN

Note: Install driver for USB-serial adapter. Communication parameters: 9600 baud, no parity, 8 data bits,1 stop bit.

Software Comparison Table

Common Pitfalls

1. XG5000 cannot recognize K7M-DR14UE. Use XBC series if new replacement required.
2. Running KGLWIN on Win10/11: XP compatibility mode + run as administrator.
3. Communication failure: Check USB-serial driver, COM port number, baud rate, RS232 wiring.

Supported Operating Systems for KGLWIN (for K7M K120S PLC)

Officially supported OS (per manual): Windows 95, Windows 98, Windows 2000, Windows XP (32-bit)

✅ Practical field operation (not official native support, run via compatibility mode)

1. Windows7 (32bit /64bit) : Most stable modern OS, preferred for industrial commissioning
2. Windows10 (64bit) : Require XP compatibility mode + run as administrator. USB-RS232 driver is the main issue. LTSC version performs better than home edition.
3. Windows11 (64bit) : Operable but unstable, occasional crash & serial communication anomaly, not recommended for primary commissioning.

❌ Unsupported

MacOS, Linux (no native release; can run via virtual machine with XP/Win7)

Windows ARM edition (Surface ARM laptops, abnormal execution)

Windows S mode

⚙️ Configuration Steps for Win10/11

1. Right-click KGLWIN.exe → Properties → Compatibility
2. Check: Run this program in compatibility mode for: Windows XP (Service Pack3)
3. Check: Run this program as an administrator
4. Disable antivirus/Defender real-time protection to avoid serial port driver interception
5. Communication depends on USB to RS232 (CH340/PL2303). Industrial-grade serial converter is preferred.

💡 Practical Engineering Suggestion

Maintenance for legacy K120S (K7M-DR14UE): Prepare Win7 32-bit industrial PC, highest online success rate.

If only Win10/11 available: Install XP on virtual machine, pass-through USB serial adapter to VM; much more stable than running KGLWIN directly on host OS.

Full Model List for LS MASTER-K120S (K7M) CPU

Series Description:

UE = economical type (2K program steps, AC220V power). K7M-DR14UE belongs to this group

U = standard type (7K program steps, AC220V)

U/DC = standard type DC24V power supply

DR: Relay Output; DT: NPN Transistor Output; DRT: Mixed Relay + Transistor Output

1. UE Economical Series (AC220V, 2K steps)

2. U Standard Series (AC220V,7K steps)

3. U/DC Standard DC Power Series (DC24V power,7K steps)

K7M-DR10U/DC, K7M-DR14U/DC, K7M-DT10U/DC, K7M-DT14U/DC

K7M-DR20U/DC, K7M-DT20U/DC, K7M-DRT20U/DC

K7M-DR30U/DC, K7M-DT30U/DC, K7M-DRT30U/DC

K7M-DR40U/DC, K7M-DT40U/DC, K7M-DRT40U/DC

K7M-DR60U/DC, K7M-DT60U/DC, K7M-DRT60U/DC

4. Special Models

K7M-EL60A: Elevation dedicated K120S CPU

5. K120S Expansion Modules G7E Series (matched with above CPU)

Digital Modules

G7E-DR10A (6DI+4DO Relay), G7E-DR20A (12DI+8DO Relay)

G7E-TR10A (10-point transistor output), G7E-RY08A (8-point relay output)

G7E-DC08A (8-point DC input), G7E-DR08A (4DI+4DO Relay)

Analog Modules

G7F-AD2A 2-channel AI; G7F-DA2I 2-channel AO; G7F-ADHB 4-channel high-speed AD

G7F-RD2A RTD PT100; G7F-TC2A Thermocouple module

Communication Special Modules

G7L-CUEB, G7L-CUEC C-net communication module

⚠️ Replacement Reminder

1. UE economical model only has 2K program steps, cannot directly replace U standard model (7K). Download error occurs when program exceeds 2K steps.
2. DR relay output cannot send pulse for positioning; DT transistor model for pulse output; DRT mixed model handles both switch signal & pulse.
3. All K120S (K7M) discontinued. Programming software is KGLWIN, XG5000 not supported.

Engineering Application Cases for K7M-DR14UE

Precondition: Pure digital logic, limited high-speed counting; relay output without high-frequency positioning pulse; program capacity limit 2K steps. Suitable for small standalone machines & legacy equipment retrofit.

Case 1: Flameproof Distribution Switch Control for Underground Mining (Classic Real Project)

I/O Assignment: 8DI: Overload, leakage, door interlock, emergency stop, test button, status feedback; 6DO: Close command, trip command, fault alarm, run indicator, test output

System Architecture: K7M-DR14UE本体, RS485 upload signal to surface HMI/host, remote collection & alarm for switch status

Logic: Leakage lockout, overload time-delay trip, door interlock (closing prohibited with cabinet open), fault latch; high-speed counter for pulse current signal

Selection reason: AC wide voltage 85~264V, noise immunity input filter; built-in RS485, compact size for flameproof enclosure; relay output drives intermediate relay for main circuit

Limitation: Only protection logic, no complex calculation, short program well within 2K step limit

Case 2: Small Belt Conveyor / Assembly Line Standalone Control

I/O Assignment: DI: Start button, stop, emergency stop, belt deviation sensor, material level, block feedback; DO: Main contactor, buzzer alarm, run lamp, fault lamp, belt cleaner solenoid valve

Process: Sequential belt start/stop, delay start/stop, fault shutdown + audible & visual alarm, deviation protection, auto start/stop based on material level; manual / auto mode switch

Optional accessories: Touch screen via RS232/485 for fault code viewing; multi-conveyor 1:N interlock via RS485 network

Important: Relay output suitable for contactor coil; Do NOT drive high-power load directly with PLC relay, add intermediate relay for isolation.

Case3: Auxiliary Packaging Machine (Discharging, Material stopper, Cylinder sequence action)

Usage: Small packaging auxiliary station, material stopper cylinder, material detection, counting, auto stop when bin full

DI: Photoelectric sensor, low material detection, cylinder position magnetic switch, start/reset; DO: Solenoid valve, indicator lamp, alarm

Process: Material detected → stopper cylinder extend → discharge → delay retract, finished product counting, auto stop at full bin; high-speed counter for product count

Limitation: Cannot control servo/stepper positioning (DR relay no pulse output); replace with DT transistor version if positioning required.

Case4: Small HVAC / Air Handling Unit (Fresh air unit, simple constant temperature cabinet logic)

DI: Differential pressure switch, freeze protection switch, fan overload, manual-auto selector; DO: Fan contactor, motorized damper, alarm

Solution: CPU only for digital interlock; external G7F-RD2A/TC2A analog module for PT100 / thermocouple temperature sampling if PID needed

Logic: Fan & damper interlock, freeze protection, differential pressure alarm, fault shutdown; RS485 connect to building SCADA for remote monitoring

Case5: LV Cabinet / Control Cabinet Logic Monitoring Unit (Switchgear status acquisition)

DI: Circuit breaker on/off feedback, spring charged status, cabinet door limit, fault signal; DO: Close circuit, fault alarm, indicator lamp

Function: Switchgear status collection, fault latch, remote upload. Widely used in legacy cabinet retrofit project, low-cost replacement for old relay logic

Advantage: AC220V power supply taken directly from cabinet control circuit, no extra DC supply required.

Case6: Simple Elevating Platform / Material Hoist (Safety interlock control)

DI: Upper/lower limit, ultimate limit, emergency stop, door interlock, manual button; DO: Up contactor, down contactor, alarm

Process: Limit protection, emergency stop latch, lifting prohibited with door open; electrical interlock to prevent simultaneous activation of up & down contactor

⚠️Safety Notice: Lifting equipment requires independent safety relay. PLC logic only acts as auxiliary control and cannot serve as sole safety circuit.

K7M-DR14UE Specific Pitfalls & Selection Tips

1. 2K step limitation: Complex process, many comments, multi-sequence steps may exceed capacity and cause download failure. Use K7M-DR14U (7K standard version) for complex projects.
2. Relay output: Not suitable for frequent switching; select DT transistor model for high-speed solenoid valves.
3. Communication: RS485 Cnet protocol for HMI & SCADA; KGLWIN software, XG5000 incompatible.
4. Expansion: Add G7E digital modules, G7F analog modules if insufficient I/O points.

Not Recommended Applications

Servo / stepper motor positioning (no pulse output)

High-frequency solenoid valves (fast contact wear)

Mass analog signal + heavy PID calculation (easy program overflow under 2K steps)

New greenfield projects (discontinued, LS XBC series preferred)