Modicon TM2 Discrete Output Expansion Module, for M238 / M241 PLC, Fine della vita
Full designation: TM2DDO8TT, 8-point 24VDC Source (PNP) transistor output module, removable screw terminal block
- Definizione del codice modello
TM2: TM2 series expansion I/O (Compatible with M218 / M238 / M241)
D: Digitale
FARE: Uscita digitale
8: 8 canali
T: Transistor
T: Source output (PNP); UT = Sink output (NPN)
- Specifiche elettriche principali
| Articolo | Specifica |
| Tipo di uscita | 24VDC PNP Source Transistor |
| Canali | 8 punti, shared 1 terminale comune |
| Rated current per channel | 0.5A/punto; Max total current of common terminal: 4UN |
| Intervallo di tensione operativa | 20.4 ~ 28.8 VCC |
| Tempo di risposta | 450µs (rise / fall) |
| Caduta di tensione | Max 0.4V |
| Corrente di dispersione | ≤0.1mA |
| Max inductive load | 10mH; Tungsten lamp load:12W |
| Protezione | Per-channel short-circuit & protezione da sovraccarico, auto-recovery |
| Isolamento | Channel ↔ PLC internal bus: 500Vac for 1min; Nessun isolamento tra i canali |
| terminale | Removable screw terminal block |
| Montaggio | 35Guida DIN da mm |
| Peso | 0.085kg |
| Dimensioni | W27.3 × H90 × D84.6 mm |
- Compatibilità & End-of-Life Information
- CPU compatibile: Modicon M218 / M238 / M241 PLC (TM2 local expansion); Not applicable for M221/M251
- EOL Status: Officially discontinued by Schneider SU 27 Settembre 2024. Nessuna nuova unità originale disponibile, only stock / second-hand modules on market.
- Sostituzione consigliata: TM3DQ8T (TM3 series, 8-point Source transistor output, compatible with M221/M241/M251)
⚠️ Nota: TM2 and TM3 bus hardware are not interchangeable. Direct replacement requires PLC backplane / expansion architecture modification.
- Same Series Selection Reference
TM2DDO8TT: 8FARE, PNP Source, 0.5UN, terminale a vite (EOL)
TM2DDO8UT: 8FARE, NPN Sink, 0.3UN, terminale a vite (EOL)
- Applicazione & Note sul cablaggio
- PNP Source Output: Output terminal provides +24V; negative side of load connects to 0V. Suitable for solenoid valves, spie luminose, load connected to 0V.
- Per carichi induttivi (elettrovalvole), freewheeling diode is recommended to protect transistors.
- TM2 expansion modules must be installed at the end of local expansion bus, cannot be placed before TM3 expansion modules.
- Onboard LED channel status indicators for commissioning and troubleshooting.
- Risoluzione dei problemi (Second-hand Module Inspection)
- Power on and check module power LED and bus communication LED.
- Test each output channel sequentially: When PLC output = ON, measure 24V at terminal; voltage drops when OFF.
- Short-circuit protection test: Short output to 0V, channel should cut off output automatically; output recovers once short circuit removed.
- Measure off-state leakage current to judge transistor aging.
- Inspect removable terminals for burn marks and deformed copper contacts.
- HS Code Reference
8537101100 (Programmable Controller I/O Expansion Module)
Replacement Options for TM2DDO8TT (8-point 24VDC PNP Source, TM2 Bus)
Original module: TM2DDO8TT, TM2 bus, only for M218/M238/M241, EOL; TM2 bus and TM3 bus hardware cannot be swapped directly. 3 categories for selection:
Caso 1: Keep existing M218/M238/M241 CPU, only replace expansion module
TM3 modules cannot be used. Although M241 supports both TM2+TM3 bus, TM2 modules must be installed after TM3 modules. Mixed installation is not recommended for long-term engineering use. If you need direct plug-in on TM2 expansion bus: only surplus / used TM2DDO8TT available. Schneider has no new equivalent module on TM2 bus.
Alternative spare within same EOL series: No other TM2 8-point Source DO. Only TM2DDO8UT (NPN Sink) disponibile, cannot directly swap, opposite output logic.
Caso 2: Full PLC Upgrade (Recommended for new project / major overhaul, official replacement: TM3 series)
✅ TM3DQ8T [Migliore raccomandazione]
Spec: 8-point 24VDC PNP Source transistor, 0.5Uno per canale, removable screw terminal
Compare with TM2DDO8TT: Same channel count, output type and per-channel current; Bus type is TM3, not TM2
CPU compatibile: M221 / M241 / M251 / M262
Modification effort:
- Original M241: TM3 expansion bus supported, but IO address must be reconfigured in EcoStruxure Machine Expert, IO mapping modification required in program.
- Original M218/M238: Does not support TM3 modules, CPU must be upgraded to M241/M251 together.
Other TM3 Alternatives (Same TM3 Bus)
- TM3DQ8TG: 8-point PNP Source, terminale a molla, electrical parameters same as TM3DQ8T, only wiring terminal difference
- TM3DQ16T: 16-point PNP Source, 0.5UN; spare IO channels, suitable for projects with IO reservation
Caso3: Distributed Remote IO Replacement (Keep original CPU, no local bus modification, ideal for legacy retrofit)
Advantys OTB remote IO, communicate via Modbus RTU to original PLC, independent IO station, does not occupy TM2 local expansion port
- OTB1C08T: 8-point 24V PNP Source transistor output, ModBus RTU, terminale a vite
Pro: No modification to original local expansion bus, only add Modbus read/write logic, independent installation inside cabinet. Suitable for limited cabinet space, no change to existing expansion chain.
Contro: Modbus communication program required, response speed slightly slower than local expansion module.
Caso4: Domestic Compatible Replacement (Cost-saving option, Modbus Remote IO)
Domestic Modbus RTU remote 8-channel PNP transistor output modules (Innovazione, Xinje, Lansen etc.), funzionalmente equivalenti, connect to M218/M238/M241 via Modbus. For projects with tight budget.
Selection Comparison Table
| Modello sostitutivo | Tipo di uscita | Current per Channel | Tipo di autobus | PLC compatibile | Modification Workload |
| TM2DDO8TT (Originale) | PNP Source | 0.5UN | TM2 Local Bus | M218/M238/M241 | EOL, only stock / usato |
| TM3DQ8T (Consigliato ufficiale) | PNP Source | 0.5UN | TM3 Local Bus | M241/M251/M221/M262 | ★★★☆ Reconfigure IO address & PLC program |
| OTB1C08T | PNP Source | 0.5UN | Modbus RTU Remote IO | M218/M238/M241 (No CPU change) | ★★☆ Add Modbus communication program |
⚠️ Critical Retrofit Notes
- TM2 bus and TM3 bus have different hardware connectors, cannot hot-swap directly. When mixing TM2+TM3 on M241, TM2 modules must be placed after TM3 modules; long-term mixed configuration is not recommended in engineering.
- TM2DDO8TT is PNP Source. Never select NPN Sink model (TM3DQ8U / TM2DDO8UT), opposite output logic, load will not operate after wiring.
- TM3DQ8T has different common terminal and pin assignment from TM2DDO8TT, field secondary wiring cannot reuse the original terminal plug directly; necessario il ricablaggio.
Schneider TM3DQ8T (Common miswriting: TM3DO8T)
Modicon TM3 discrete expansion output module, 8-point 24VDC PNP Source transistor output, removable screw terminal, official recommended replacement for TM2DDO8TT
- Definizione del codice modello
TM3: TM3 series local expansion I/O module
DQ: Discrete Output
8: 8 canali
T: Transistor PNP Source output (Terminale a vite)
TM3DQ8TG = identical electrical parameters, spring cage terminal version
- Specifiche elettriche principali
| Articolo | Specifica |
| Tipo di uscita | 24VDC PNP Source (positive logic) Transistor |
| Quantità di canali | 8 punti, shared one common terminal |
| Rated current per channel | 0.5A/channel |
| Max total current of common terminal | 4UN (Total limit for 8 canali) |
| Output supply voltage | 20.4 ~ 28.8 VCC (nominal 24VDC) |
| Caduta di tensione | ≤0.4V |
| Off-state leakage current | ≤0.1mA |
| Tempo di risposta | Max 450µs (rise / fall) |
| Frequenza di commutazione massima (carico resistivo) | 100Hz |
| Max incandescent lamp load | 12W |
| Carico induttivo | External freewheeling diode recommended; typical clamping voltage 50VDC |
| Protezione da cortocircuito | Per-channel independent short-circuit / protezione da sovraccarico; auto-recovery after fault removal |
| Isolation rating | Module bus ↔ output channel: 500Vac, 1min withstand; Nessun isolamento tra i canali |
| Bus power supply | 5V supplied by TM3 expansion bus; 24V for output loop must be wired separately |
| 5V bus consumption | SPENTO:5mA; SU:10mA; 24V field circuit: OFF=0mA, ON max 20mA |
- Meccanico & Specifiche ambientali
| Articolo | Specifica |
| Montaggio | 35mm DIN rail TH35-7.5 / TH35-15, or panel screw mounting |
| Dimensione complessiva | W27.4 × H90 × D84.6 mm |
| Peso netto | ca. 0.076kg |
| Classe di protezione | IP20 (Solo per installazione in armadio) |
| terminale | Removable screw terminal block, 5.08mm pitch; Filo:0.2~2,5 mm² (24~14AWG) |
| Temperatura operativa | Montaggio orizzontale: -10 ~ +55℃; Montaggio verticale: -10 ~ +35℃ |
| Temperatura di conservazione | -25 ~ +70℃ |
| Umidità relativa | 10~95%, senza condensa |
| Max working altitude | 2000M |
| Grado di inquinamento | 2 |
| Resistenza alle vibrazioni | 5~8.4Hz:3.5mm; 8.4~150Hz:3G |
| Resistenza agli urti | 15G,11SM |
| Indicatore LED | 1 green LED per channel to display ON/OFF state |
| Certificazioni | CE, cULus, UKCA, RCM, CCC |
- Compatibilità PLC
Works with Modicon M221 / M241 / M251 / M262
❗ M218, M238 do NOT support TM3 modules, cannot extend TM3DQ8T directly.
- Comparison vs Original TM2DDO8TT (Chiave)
| Parametro | TM2DDO8TT | TM3DQ8T |
| Produzione | PNP Source 0.5A, 8-point common terminal | PNP Source 0.5A, 8-point common terminal |
| Max total common current | 4UN | 4UN |
| Tempo di risposta | 450碌s | 450碌s |
| Withstand isolation | 500Vac | 500Vac |
| Autobus | TM2 Bus (M218/M238/M241) | TM3 Bus (M221/M241/M251/M262) |
| Dimensioni | W27.3 脳 H90 脳 D84.6mm | W27.4 脳 H90 脳 D84.6mm |
| Disposizione del terminale | Different pin assignment, secondary wiring cannot reuse terminal plug directly | Different pin assignment, secondary wiring cannot reuse terminal plug directly |
- Note sul cablaggio
- PNP Source: Output terminal provides +24V, load other end connects to 0V; suitable for solenoid valves and indicator lamps.
- 8 channels share one common power terminal, external +24V connects to common terminal.
- Per carichi induttivi (elettrovalvole), freewheeling diode must be paralleled to absorb back EMF and protect transistors.
- Module 5V bus power supplied by PLC backplane; 24V power for output circuit must be external.
- Fault Detection (Bench Test)
- Accendere: Check module bus LED and channel LED status.
- Activate each point sequentially: 24V measured at terminal when ON; voltage drops at OFF state.
- Short-circuit test: Short output to 0V, module triggers protection, output restores automatically after short removed.
- Measure off-state leakage current to evaluate transistor aging.
- HS Code Reference
8537101100 (PLC discrete I/O expansion module)
- Alternatives within TM3 family
TM3DQ8TG: Same specs, spring cage terminal
TM3DQ8U: 8-point NPN Sink output, opposite logic, do not select by mistake
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