Main Components of a PLC System: Complete Guide for Engineers
Master PLC system components: CPU, power supply, I/O modules, communication interfaces, and software with sizing formulas and selection tips. Shop at Stoklink.
- Part number
- 6EP1931-2EC21
- Model no
- DC UPS
Siemens has announced the end of 6EP1931-2EC21
Once production ends, supply depends on remaining stock.
No replacement announced yet. Tell us the application and we will propose an alternative.
- CE
- EAC
Siemens 6EP1931-2EC21 SITOP DC UPS Module 24 V DC/15 A DC UPS Module
Siemens SITOP 24V/15A DC UPS module with battery buffering, 96.2% efficiency, IP20, DIN rail.
Description
About the DC UPS
About the DC UPS
The Siemens SITOP 6EP1931-2EC21 is a 24 V DC uninterruptible power supply module rated for 15 A output current, drawing a 24 V/16 A DC input and bridging the connected load through an external battery module during a mains interruption. It reaches 96.2% efficiency at rated output and switches from mains to battery automatically once the input voltage falls below its adjustable 22-25.5 V threshold.
Certifications & Standards
- CE
- EAC
- Shipbuilding
- ABS
- DNV
- EPD
Selection Notes
This is the 15 A-class module in the SITOP DC UPS line, sized for continuous loads up to 15 A, with the extra 1 A of input headroom reserved for battery charging rather than the load. It has no communication interface (design of interface: without), so status is read only through the floating relay contacts for OK, Alarm, and Bat>85% rather than over a network — choose the Ethernet/PROFINET SITOP UPS1600 instead when remote diagnostics are required. The 22-25.5 V adjustable buffer threshold, set in 0.5 V steps, lets the switch-to-battery point be tuned ahead of a downstream PLC's own undervoltage cutoff.
Applications
PLC and control-rack power backup for critical loops, short mains-dropout ride-through on production lines, and bridging power during automatic transfer switch operation.
Specification
Full specification
General information 3
| product brand name | SITOP |
|---|---|
| product type designation | DC UPS |
| type of current supply | DC UPS 24 V/15 A |
Input 6
| voltage curve at input | DC |
|---|---|
| supply voltage at DC rated value | 24 V |
| input voltage at DC | 22 ... 29 V |
| adjustable response value voltage for buffer connection preset | 22.5 V |
| adjustable response value voltage for buffer connection | 22 ... 25.5 V; Adjustable in 0.5 V increments |
| input current at rated input voltage 24 V rated value | 15 A; + approx. 1 A with empty battery |
Memory 3
| type of energy storage | with batteries |
|---|---|
| product function DC-UPS modularly expandable | Yes |
| design of the mains power cut bridging-connection | Dependent on connected battery and load current, see selection table battery module and mains buffering times as well as the relevant important information notes! |
Show all 91 specifications ↓ Show less ↑79 more values in Identification, Output, Efficiency, Protection and monitoring, Interfaces, Safety, Standards, specifications, approvals, Standards, specifications, approvals marine classification, Standards, specifications, approvals Environmental Product Declaration, Ambient conditions, Connection method, Mechanical data, Accessories, Additional information, Logistics.
Identification 10
| Part number | 6EP1931-2EC21 |
|---|---|
| Type designation | DC UPS |
| Brand | Siemens |
| Condition | New, factory sealed |
| Source | Siemens and its authorised distributors |
| Warranty | Manufacturer warranty |
| Lifecycle status | Phase-out announced by the manufacturer |
| EAN | 4025515151043 |
| ETIM class | EC000382 |
| eCl@ss | 27040705 |
Output 12
| output voltage: in normal operation at DC rated value | 24 V |
|---|---|
| output voltage: in buffering mode at DC rated value | 24 V |
| formula for output voltage | Vin - approx. 0.5 V |
| startup delay time typical | 1 s |
| voltage increase time of the output voltage typical | 60 ms |
| output voltage in buffering mode at DC | 19 ... 28.5 V |
| output current: rated value | 15 A |
| output current: in normal operation | 0 ... 15 A |
| output current: in buffering mode | 0 ... 15 A |
| peak current | 15.7 A |
| property of the output short-circuit proof | Yes |
| charging current | 0.35 A, 0.7 A |
Efficiency 5
| efficiency in percent: at rated output voltage for rated value of the output current typical | 96.2 % |
|---|---|
| efficiency in percent: in case of operation on rechargeable battery typical | 96 % |
| power loss [W]: at rated output voltage for rated value of the output current typical | 14 W |
| power loss [W]: in case of operation on rechargeable battery typical | 15 W |
| supplied active power typical | 360 W |
Protection and monitoring 4
| product function: reverse polarity protection against energy storage unit polarity reversal | Yes |
|---|---|
| product function: reverse polarity protection against input voltage polarity reversal | Yes |
| display version: for normal operation | Normal operation: LED green (OK), floating changeover contact "Bat/OK" to setting "OK" ("OK" means: Voltage of the supplying power supply unit is greater than cut-in threshold set at the DC UPS module); Lack of buffer standby: LED red (alarm), floating changeover contact "Alarm/Bat" to setting "Alarm"; Battery replacement required: LED red (alarm) flashing with approx. 0.25 Hz, floating changeover contact "Alarm/Bat" switching with approx. 0.25 Hz; Energy storage > 85%: LED green (Bat > 85%), floating NOcontact "Bat > 85" closed; Permissible contact current capacity: DC 60 V/1 A or AC 30 V /1 A |
| display version: in buffering mode | Buffered mode: LED yellow (Bat), floating changeover contact "OK/Bat" to setting "Bat"; Prewarning battery voltage 85%: LED green (Bat > 85%), floating NO contact "Bat > 85" closed |
Interfaces 3
| product component PC interface | No |
|---|---|
| product function communication function | No |
| design of the interface | without |
Safety 5
| galvanic isolation between input and output | No |
|---|---|
| operating resource protection class | Class III |
| protection class IP | IP20 |
| standard: for emitted interference | EN 55022 Class B |
| standard: for interference immunity | EN 61000-6-2 |
Standards, specifications, approvals 4
| certificate of suitability: CE marking | Yes |
|---|---|
| certificate of suitability: UL approval | Yes; cULus-Listed (UL 508, CSA C22.2 No. 107.1), File E197259 |
| certificate of suitability: EAC approval | Yes |
| MTBF at 40 °C | 791 139 h |
Standards, specifications, approvals marine classification 3
| shipbuilding approval | Yes |
|---|---|
| Marine classification association: American Bureau of Shipping Europe Ltd. (ABS) | Yes |
| Marine classification association: Det Norske Veritas (DNV) | Yes |
Standards, specifications, approvals Environmental Product Declaration 5
| Environmental Product Declaration | Yes |
|---|---|
| global warming potential [CO2 eq]: total | 397.1 kg |
| global warming potential [CO2 eq]: during manufacturing | 16.4 kg |
| global warming potential [CO2 eq]: during operation | 380.3 kg |
| global warming potential [CO2 eq]: after end of life | 0.3 kg |
Ambient conditions 4
| ambient temperature: during operation | -25 ... +60 °C; with natural convection |
|---|---|
| ambient temperature: during transport | -40 ... +85 °C |
| ambient temperature: during storage | -40 ... +85 °C |
| environmental category according to IEC 60721 | Climate class 3K3, 5 ... 95% no condensation |
Connection method 5
| type of electrical connection | screw terminal |
|---|---|
| at input | 24 V DC: 2 screw terminals for 1 ... 4 mm2/17 ... 11 AWG |
| at output | 24 V DC: 4 screw terminals for 1 ... 4 mm2/17 ... 11 AWG |
| for rechargeable battery module | 24 V DC: 2 screw terminals for 1 ... 4 mm2/17 ... 11 AWG |
| for control circuit and status message | 10 screw terminals for 0.5 ... 2.5 mm2/20 ... 13 AWG |
Mechanical data 11
| width × height × depth of the enclosure | 50 × 125 × 125 mm |
|---|---|
| installation width × mounting height | 50 mm × 225 mm |
| required spacing: top | 50 mm |
| required spacing: bottom | 50 mm |
| required spacing: left | 0 mm |
| required spacing: right | 0 mm |
| fastening method | Snaps onto DIN rail EN 60715 35x7.5/15 |
| DIN-rail mounting | Yes |
| S7 rail mounting | No |
| wall mounting | No |
| housing can be lined up | Yes |
Accessories 1
| electrical accessories | Battery module |
|---|
Additional information 1
| other information | Specifications at rated input voltage and ambient temperature +25 °C (unless otherwise specified) |
|---|
Logistics 6
| Net weight | 0.4 kg |
|---|---|
| Country of origin | Romania |
| Shipping weight | 0.9 kg |
| Ships from | Türkiye |
| Dispatch | — |
| Stock | On request |
Source: manufacturer data · Last verified: 01 Nov 2026
Documents
Documents for 6EP1931-2EC21
No documents are on file for this part yet.
Ask us for the datasheet
Certifications
Certifications and standards
- CE
- EAC
- CE marking
- EAC approval
- shipbuilding approval
- American Bureau of Shipping Europe Ltd. (ABS)
- Det Norske Veritas (DNV)
- Environmental Product Declaration
Quick answers
Questions about the DC UPS
What is the rated current of DC UPS?
The rated current of DC UPS is 15 A.
Which supply voltage is DC UPS rated for?
The rated operational voltage of DC UPS is 24 V AC.
What motor power is DC UPS rated for?
The rated motor power of DC UPS is 96.2 % kW.
What is the HS code of DC UPS for customs?
The tariff (HS) code on file for DC UPS is 85044060.
What is the EAN of DC UPS?
The EAN (GTIN) of DC UPS is 4025515151043.
Where does DC UPS ship from, and how fast?
DC UPS ships from Türkiye. Shipping calculated at checkout · import duties and taxes paid on arrival.
Guides
Guides for power supplies
Reviews
Customer reviews
Series
Siemens SITOP DC
- Brand
- Siemens
- Series
- SITOP DC
