Modicon TM2 Discrete Output Expansion Module, for M238 / M241 PLC, End of Life
Désignation complète: TM2DDO8TT, 8-point 24VDC Source (PNP) transistor output module, removable screw terminal block
- Définition du code modèle
TM2: TM2 series expansion I/O (Compatible with M218 / M238 / M241)
D: Numérique
FAIRE: Sortie numérique
8: 8 chaînes
T: Transistor
T: Sortie source (PNP); UT = Sink output (NPN)
- Principales spécifications électriques
| Article | Spécification |
| Type de sortie | 24VDC PNP Source Transistor |
| Canaux | 8 points, shared 1 borne commune |
| Rated current per channel | 0.5A/point; Max total current of common terminal: 4UN |
| Plage de tension de fonctionnement | 20.4 ~ 28.8 VCC |
| Temps de réponse | 450µs (rise / fall) |
| Voltage drop | Max 0.4V |
| Courant de fuite | ≤0.1mA |
| Max inductive load | 10mH; Tungsten lamp load:12W |
| Protection | Per-channel short-circuit & protection contre les surcharges, récupération automatique |
| Isolement | Channel ↔ PLC internal bus: 500Vac for 1min; No isolation between channels |
| Terminal | Removable screw terminal block |
| Montage | 35mm rail DIN |
| Poids | 0.085kilos |
| Dimensions | W27.3 × H90 × D84.6 mm |
- Compatibilité & End-of-Life Information
- Processeur compatible: Modicon M218 / M238 / M241 PLC (TM2 local expansion); Not applicable for M221/M251
- EOL Status: Officially discontinued by Schneider sur 27 Sep 2024. No new original units available, only stock / second-hand modules on market.
- Remplacement recommandé: TM3DQ8T (TM3 series, 8-point Source transistor output, compatible with M221/M241/M251)
⚠️ Remarque: TM2 and TM3 bus hardware are not interchangeable. Direct replacement requires PLC backplane / expansion architecture modification.
- Référence de sélection de la même série
TM2DDO8TT: 8FAIRE, Source PNP, 0.5UN, borne à vis (EOL)
TM2DDO8UT: 8FAIRE, Évier NPN, 0.3UN, borne à vis (EOL)
- Application & Remarques sur le câblage
- PNP Source Output: Output terminal provides +24V; negative side of load connects to 0V. Suitable for solenoid valves, voyants lumineux, load connected to 0V.
- Pour charges inductives (électrovannes), 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.
- Dépannage (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:
Cas 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 (Évier NPN) disponible, cannot directly swap, opposite output logic.
Cas 2: Full PLC Upgrade (Recommended for new project / major overhaul, official replacement: TM3 series)
✅ TM3DQ8T [Meilleure recommandation]
Spec: 8-point 24VDC PNP Source transistor, 0.5Un par canal, removable screw terminal
Compare with TM2DDO8TT: Same channel count, output type and per-channel current; Bus type is TM3, not TM2
Processeur compatible: 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, borne à ressort, 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
Cas3: 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, borne à vis
Avantages: 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.
Inconvénients: Modbus communication program required, response speed slightly slower than local expansion module.
Cas4: Remplacement compatible domestique (Cost-saving option, Modbus Remote IO)
Domestic Modbus RTU remote 8-channel PNP transistor output modules (Innovation, Xinje, Lansen etc.), fonctionnellement équivalent, connect to M218/M238/M241 via Modbus. For projects with tight budget.
Selection Comparison Table
| Modèle de remplacement | Type de sortie | Courant par canal | Bus Type | Compatible PLC | Modification Workload |
| TM2DDO8TT (Original) | Source PNP | 0.5UN | TM2 Local Bus | M218/M238/M241 | EOL, only stock / utilisé |
| TM3DQ8T (Officiel recommandé) | Source PNP | 0.5UN | TM3 Local Bus | M241/M251/M221/M262 | ★★★☆ Reconfigure IO address & PLC program |
| OTB1C08T | Source PNP | 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; rewiring required.
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
- Définition du code modèle
TM3: TM3 series local expansion I/O module
QD: Discrete Output
8: 8 chaînes
T: Transistor PNP Source output (Borne à vis)
TM3DQ8TG = identical electrical parameters, spring cage terminal version
- Spécifications électriques de base
| Article | Spécification |
| Type de sortie | 24VDC PNP Source (positive logic) Transistor |
| Quantité de canaux | 8 points, shared one common terminal |
| Rated current per channel | 0.5Un/canal |
| Max total current of common terminal | 4UN (Total limit for 8 chaînes) |
| Output supply voltage | 20.4 ~ 28.8 VCC (nominal 24 V CC) |
| Voltage drop | ≤0.4V |
| Courant de fuite hors état | ≤0.1mA |
| Temps de réponse | Max 450µs (rise / fall) |
| Fréquence de commutation maximale (charge résistive) | 100Hz |
| Max incandescent lamp load | 12W |
| Charge inductive | External freewheeling diode recommended; typical clamping voltage 50VDC |
| Protection contre les courts-circuits | Per-channel independent short-circuit / protection contre les surcharges; auto-recovery after fault removal |
| Isolation rating | Module bus ↔ output channel: 500Vac, 1min withstand; No isolation between channels |
| Bus power supply | 5V supplied by TM3 expansion bus; 24V for output loop must be wired separately |
| 5V bus consumption | DÉSACTIVÉ:5mA; SUR:10mA; 24V field circuit: OFF=0mA, ON max 20mA |
- Mécanique & Spécifications environnementales
| Article | Spécification |
| Montage | 35mm DIN rail TH35-7.5 / TH35-15, or panel screw mounting |
| Dimension hors tout | W27.4 × H90 × D84.6 mm |
| Poids net | Environ. 0.076kilos |
| Classe de protection | IP20 (Pour installation en armoire uniquement) |
| Terminal | Removable screw terminal block, 5.08mm pitch; Fil:0.2~2,5 mm² (24~14AWG) |
| Température de fonctionnement | Montage horizontal: -10 ~ +55℃; Montage vertical: -10 ~ +35℃ |
| Température de stockage | -25 ~ +70℃ |
| Humidité relative | 10~95 %, sans condensation |
| Max working altitude | 2000m |
| Degré de pollution | 2 |
| Résistance aux vibrations | 5~8.4Hz:3.5mm; 8.4~150Hz:3g |
| Résistance aux chocs | 15g,11MS |
| Indicateur LED | 1 green LED per channel to display ON/OFF state |
| Certifications | CE, cULus, UKCA, MRC, CCC |
- Compatibilité automate
Works with Modicon M221 / M241 / M251 / M262
❗ M218, M238 do NOT support TM3 modules, cannot extend TM3DQ8T directly.
- Comparison vs Original TM2DDO8TT (Clé)
| Paramètre | TM2DDO8TT | TM3DQ8T |
| Sortir | PNP Source 0.5A, 8-point common terminal | PNP Source 0.5A, 8-point common terminal |
| Max total common current | 4UN | 4UN |
| Temps de réponse | 450碌s | 450碌s |
| Withstand isolation | 500Vac | 500Vac |
| Bus | TM2 Bus (M218/M238/M241) | TM3 Bus (M221/M241/M251/M262) |
| Dimensions | W27.3 脳 H90 脳 D84.6mm | W27.4 脳 H90 脳 D84.6mm |
| Disposition des terminaux | Different pin assignment, secondary wiring cannot reuse terminal plug directly | Different pin assignment, secondary wiring cannot reuse terminal plug directly |
- Remarques sur le câblage
- Source PNP: 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.
- Pour charges inductives (électrovannes), 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)
- Allumer: 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
Contacteur,disjoncteur,capteur,Encodeur,API,Convertisseur















NH42-63-318x560.png)



