TO MITSUBISHI FX5U: I/O MAP (PNP SOURCE, X0/X1/X2)
ENGINEER-READY. Standardize how a safety light curtain’s OSSD1/OSSD2, EDM, and RESET are mapped to MITSUBISHI FX5U digital inputs (PNP sourcing example). Includes a copy-ready I/O list, naming rules, sample program (ST/Ladder-style), and commissioning checklist.
NAMING CONVENTION
| TAG | MEANING | NOTES |
|---|---|---|
LC_OSSD_CH_A | LIGHT CURTAIN OSSD CHANNEL A | MAP → X0 (PNP) |
LC_OSSD_CH_B | LIGHT CURTAIN OSSD CHANNEL B | MAP → X1 (PNP) |
LC_EDM_FB | EDM FEEDBACK FROM K1/K2 NC | MAP → X2 (PNP) |
LC_RST_BTN | MANUAL RESET PUSHBUTTON | MAP → X3 (RISING-EDGE) |
LC_STATUS_OK | DERIVED “OK” STATE | INTERNAL BIT M100 |
LC_INTERLOCK | ENABLE-TO-START INTERLOCK | INTERNAL BIT M101 |
POLARITY RULE: FOR PNP SOURCING, THE FX5U INPUT COMMON COM = 0V, AND SENSOR OUTPUTS SOURCE +24V INTO X-INPUTS.
PNP WIRING OVERVIEW (TEXT DIAGRAM)
LIGHT CURTAIN (TX/RX)
OSSD1 ─────────────► X0 (FX5U)
OSSD2 ─────────────► X1 (FX5U)
EDM FB (K1 NC ─┐
├──────► X2 (FX5U)
K2 NC ─┘
RESET PB ──────► X3 (FX5U, RISING EDGE)
0V (COM) ──────► FX5U COM (TIED TO 0V FOR PNP)
+24V SUPPLY ───► SENSOR & RELAY (SEPARATE BREAKER)
SAFETY RELAY
OUT 13-14 ───► CONTACTOR K1 COIL
OUT 23-24 ───► CONTACTOR K2 COIL
AUX 41-42 ───► PLC DIAGNOSTIC INPUT (OPTIONAL)- SEPARATE OSSD1/OSSD2 HARNESSES & PROTECTION — NO SHARED FUSE.
- EDM USES SERIES NC CONTACTS OF K1/K2 BACK TO PLC/RELAY INPUT.
- RESET MUST BE RISING-EDGE OR TWO-STAGE. HOLD-TO-RESET IS PROHIBITED.
- KEEP POWER CABLES ≥ 200 MM AWAY FROM SIGNALS; CROSS AT 90°.
I/O MAP (COPY-READY)
| VARIABLE | FX5U ADDRESS | SOURCE | PURPOSE | REMARKS |
|---|---|---|---|---|
LC_OSSD_CH_A | X0 | OSSD1 | SAFETY CHANNEL A | PNP (COM=0V) |
LC_OSSD_CH_B | X1 | OSSD2 | SAFETY CHANNEL B | DESYNC → FAULT |
LC_EDM_FB | X2 | K1/K2 NC | EDM FEEDBACK | BLOCK RESET IF OPEN |
LC_RST_BTN | X3 | PUSHBUTTON | MANUAL RESET | RISING EDGE ONLY |
LC_STATUS_OK | M100 | LOGIC | LIGHT CURTAIN OK | DERIVED |
LC_INTERLOCK | M101 | LOGIC | ENABLE-TO-START | AUTO-CANCEL ON FAULT |
SAMPLE PROGRAM (ST-STYLE, FX5U)
// NOTE: EXAMPLE ONLY—ADAPT TO YOUR LIBRARIES/STANDARDS.
// STATUS OK WHEN BOTH OSSDs AND EDM ARE TRUE.
IF X0 AND X1 AND X2 THEN
M100 := TRUE; // LC_STATUS_OK
ELSE
M100 := FALSE;
END_IF;
// RISING-EDGE OF RESET BUTTON.
VAR
_rstPrev : BOOL := FALSE;
END_VAR
IF (X3 = TRUE) AND (_rstPrev = FALSE) AND (M100 = TRUE) THEN
M101 := TRUE; // LC_INTERLOCK (ENABLE-TO-START)
END_IF;
_rstPrev := X3;
// AUTO-CANCEL INTERLOCK WHEN STATUS LOST.
IF NOT M100 THEN
M101 := FALSE;
END_IF;
// OPTIONAL: ONE-SHOT IMPLEMENTATION CAN BE REPLACED BY PLC K401 EDGE INSTRUCTIONS IN LADDER.FOR TWO-STAGE RESET, REQUIRE PRESS → RELEASE → PRESS WITH A 0.5–3 S WINDOW AND DEBOUNCING.
COMMISSIONING & SELF-TEST
- POLARITY: VERIFY COM=0V FOR PNP; CHECK 24 V/0 V AND PE.
- CHANNEL COHERENCE: BLOCK/RELEASE BEAMS — X0/X1 MUST CHANGE TOGETHER; DESYNC → FAULT.
- EDM: MECHANICALLY HOLD A CONTACTOR; RESET MUST BE INHIBITED.
- RESET: LONG-PRESS INEFFECTIVE; ONLY RISING-EDGE/TWO-STAGE ACCEPTED.
- RECORDS: ARCHIVE I/O LIST, ISO 13855 CALCULATION, WAVEFORMS/LEVELS.
SELF-TEST RECORD (CSV COPY)
Item,Test,Expected,Actual,Result,Notes
1,OSSD1/OSSD2 simultaneous,Both channels change together,,,
2,Desync detection,Fault on mismatch,,,
3,EDM welded-contact block,Reset inhibited when K1/K2 held,,,
4,Reset behavior,Only rising-edge/two-stage accepted,,,
5,Interlock cancel,LC_INTERLOCK clears on status loss,,,
COMMON ERRORS & FIXES
| MISTAKE | SYMPTOM | FIX |
|---|---|---|
| SHARED PROTECTION FOR OSSD1/2 | SINGLE-POINT FAILURE HIDDEN | SEPARATE HARNESSES/FUSES |
| EDM LOOP OMITTED | RESET POSSIBLE WITH WELDED CONTACTOR | SERIES NC OF K1/K2 BACK TO INPUT |
| RESET HELD CONTINUOUSLY | UNINTENDED RESTARTS | EDGE/TWO-STAGE ONLY |
| MIXED PNP/NPN ON SAME COMMON | INPUTS STUCK ON/OFF | UNIFY POLARITY; SEGREGATE COMMONS |
FAQ
WHY PNP INSTEAD OF NPN?
INDUSTRY INTEROPERABILITY AND DIAGNOSTIC CLARITY. WITH FX5U, SET COM=0V FOR PNP SOURCING. NPN IS POSSIBLE ONLY IF THE INPUT COMMON IS TIED TO +24 V AND THE SENSOR POLARITY MATCHES.
CAN THE PLC CUT THE SAFETY CIRCUIT?
NO. SAFETY STOP IS PERFORMED BY A SAFETY RELAY/CONTROLLER DRIVING K1/K2. PLC HANDLES STATUS AND INTERLOCKS ONLY.
HOW DO I LOG RESET ATTEMPTS?
CREATE A ONE-SHOT COUNTER ON THE RISING EDGE OF X3 AND STORE TIMESTAMPS TO A RING BUFFER FOR AUDIT TRAILS.