How to Select an Interface Relay for PLC Outputs
A step-by-step guide to matching PLC output type, coil voltage and current, contact rating, and socket style when selecting an interface relay.
The Siemens 6ES7921-5AJ00-0AA0 is a SIMATIC TOP connect front connector module for digital 2 A output modules on the S7-1500. It provides a single 16-pole IDC connector for the field cabling and feeds potential supply through 4 push-in terminals, rated 24 V DC at up to 1 A per plug-in contact.
This push-in module pairs with the same 8-channel 2 A digital output card as the screw-terminal 6ES7921-5AD00-0AA0, but conductors clamp in at 0.5-1.5 mm² without a screwdriver. The single 16-pole IDC connector and one plug-in contact keep it dedicated to that output card rather than a 32-channel I/O module. Pick it for panels standardized on push-in wiring; pick the screw version where a wider conductor range or screw-terminal consistency with the rest of the cabinet matters more.
| target system | SIMATIC S7-1500 |
|---|---|
| suitability for use | 2A Output module |
| product brand name | SIMATIC Top connect |
| product type designation | Fully modular connection |
| product designation | Front connector module |
| operating voltage / at DC: rated value | 24 V |
|---|---|
| operating voltage / at DC: maximum | 60 V |
| current / rated value | 1 A |
| continuous current / at DC / per plug-in contact / maximum | 1 A |
| total current / maximum | 3 A; for mounting position horizontal |
| number of poles | 40; of the front connector |
|---|---|
| Product component / with shield | No |
| type of electrical connection / for connecting cable | Plug-in connection |
| number of poles / at the 1st interface | 16; the IDC connector for the connection cable |
| number of the plug contacts / of the electrical connection | 1 |
| wire length / maximum | 30 m; between front connector module and terminal module |
| number of terminals | 4; 2 x 1 x L+, 2 x 1 x M |
| type of electrical connection / for power supply | Push-In terminal |
| position / of the terminal | at the top |
| type of connectable conductor cross-sections / solid | No |
| connectable conductor cross-section: for flexible conductor / with core end processing | 0.25 ... 1.5 mm2; End sleeve according to DIN 46228/1 or DIN 46228/4 with plastic collar max. 0.75 mm2 |
| connectable conductor cross-section: stranded | 0.5 ... 1.5 mm2 |
| connectable conductor cross-section: finely stranded / without core end processing | 0.5 ... 1.5 mm2 |
| connectable conductor cross-section: finely stranded / with core end processing | 0.25 ... 1.5 mm2 |
| type of wire end sleeve: with plastic sleeve / according to DIN 46228-4 | Length 8mm to 9mm |
| type of wire end sleeve: without plastic sleeve / according to DIN 46228-1 | Length 8mm to 9mm |
| number of cables / per connection | 2; Connection for internal system: Combination of 1 or 2 Wires until the sum total of cross sections be achieved in a ferrule. |
| stripped length | 8 mm |
| outer diameter / of the wire insulation | 3.1 mm; to the connection of the supply terminal |
| width of screwdriver blade | 3.5 mm |
| Part number | 6ES7921-5AJ00-0AA0 |
|---|---|
| Type designation | Fully modular connection |
| Brand | Siemens |
| Condition | New, factory sealed |
| Source | Siemens and its authorised distributors |
| Warranty | Manufacturer warranty |
| Lifecycle status | Active, in production |
| EAN | 4019169845557 |
| ETIM class | EC000237 |
| eCl@ss | 27242220 |
| certificate of suitability / cULus approval | Yes |
|---|---|
| design tested acc. to type of protection / EEx e | No |
| overvoltage category | 2 |
| degree of pollution | 2 |
| operating temperature | 0 ... 60 °C |
|---|---|
| ambient temperature: during operation | 0 ... 60 °C |
| ambient temperature: during storage | -40 ... +70 |
| mounting type | direct mounting |
|---|---|
| color / of the enclosure | black |
| product feature / transparent | No |
| material / of the insulating body | other |
| product component / required / end cover plate | No |
| manufacturer's article number / of device connector / usable | replacement for S7-1500 40 pole |
|---|---|
| other information | technical specifications apply to rated input voltage values and +25 °C ambient temperature (if not otherwise specified) |
| marketing text | The front connector module for SIMATIC S7-1500 with spring terminals for potential feed to connect 16-pole cables represents a modified front connector for connection to a digital 2 Ampere out module. This is plugged into the module to be wired instead of the front connector. Here the cables are plugged in and connected to the connection module.This modified front connector module is part of the fully modular connection of SIMATIC TOP connect for the fastest and safest system cabling. In addition to low wiring costs, error sources in cabling can be significantly reduced. Sensors and actuators from the peripherals are attached to the connection modules of SIMATIC TOP connect and linked to the SIMATIC S7-300 via connecting cable and front plug-in module. |
| Net weight | 0.08 kg |
|---|---|
| Country of origin | DE |
| Shipping weight | 0.58 kg |
| Ships from | Türkiye |
| Dispatch | — |
| Stock | On request |
Source: manufacturer data · Last verified: 01 Nov 2026
No documents are on file for this part yet.
Ask us for the datasheetThe rated current of Fully modular connection is 1 A.
The rated operational voltage of Fully modular connection is 24 V DC.
The tariff (HS) code on file for Fully modular connection is 85366990.
The EAN (GTIN) of Fully modular connection is 4019169845557.
Fully modular connection ships from Türkiye. Shipping calculated at checkout · import duties and taxes paid on arrival.
A step-by-step guide to matching PLC output type, coil voltage and current, contact rating, and socket style when selecting an interface relay.
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