Product

DC UPS module 15 A

Power supply, type

15 A

Order No.

6EP1 931-2EC21¹⁾
6EP1 931-2EC31 (with serial interface)
6EP1 931-2EC42 (with USB interface)

Input L+/M in normal operation

Controlled DC voltage

Rated voltage U_{in rated}²⁾

24 V DC

Voltage range

22 ... 29 V DC

Connection threshold for battery

22.5 V DC ± 0.1 V (factory setting),
adjustable in the range 22 ... 25.5 V DC (in 0.5 V increments)

Rated current I_{in rated}

15 A + approx. 1 A with empty battery

Mains buffering

Line buffering or buffer time

Dependent on connected battery and load current, see selection table battery module and mains buffering times as well as the relevant important information notes!

On/off control circuit

External isolated NO contact required (loading max. 15 V DC/max. 10 mA).
With an open control circuit, the battery is isolated from output L+, thus canceling line buffering. If there is no input voltage, a quiescent current of approximately 0.3 mA is drawn from the battery disconnected from the output.

Methods of setting the buffering time

Adjustable using DIP switches to a maximum buffering time up to forced shutdown through exhaustive discharge protection (at approx. 19 V) or to a time limit of 5 ... 635 s
(in 10 s increments)

Interruption

Adjustable using DIP switch, either:

• Interruption of the output voltage despite returning input voltage for min. 5 s following expiry of set buffering time to support automatic restarting of industrial PCs
• No forced interruption on expiry of the set buffer time

Output L+/M in normal operation

Rated voltage U_out rated

24 V DC (output voltage of SITOP power supply)

Voltage range

Input voltage U_in less approx. 0.5 V DC

Startup delay

Approx. 1 s

Voltage rise

Typ. 60 ms

Output current I_out

0 ... 15 A

Dynamic current with overload

Electronic current limitation to 1.05 ... 1.4 x I_{out rated} for approx. 80 ms, then electronic shutdown of the output with automatic restart attempts (approx. 20 s intervals between restart attempts)

Dynamic current with short-circuit

Electronic current limitation to 1.5 ... 3 x I_{out rated} for approx. 20 ms, then electronic shutdown of the output with automatic restart attempts (approx. 20 s intervals between restart attempts)

Output L+/M with battery operation

Rated voltage U_out rated

24 V DC (from battery module)

Approximate voltage range

27 ... 19 V DC at I_out = 0.05 x C x 1/h or
24 V at I_out = 1 x C x 1/h or
23 V at I_out = 2 x C x 1/h
(C = total connected battery capacity in Ah), 19 V disconnection threshold for exhaustive discharge protection

Output current I_out³⁾

0 ... 15 A (permanently permissible)

Dynamic current with overload

Electronic current limitation to 1.05 ... 1.4 x I_{out rated} for approx. 80 ms, then buffering switch-off of output (restart following return to normal operation)

Dynamic current with short-circuit

Electronic current limitation to 1.5 ... 3 x I_{out rated} for approx. 20 ms, then buffering switch-off of output (restart following return to normal operation)

Output +Bat/-Bat in normal operation

I-V charging characteristic
(first constant current I, then constant voltage U)

End-of-charge voltage U

26.6 V DC ± 0.1 V (factory setting for +40°C battery temperature),
adjustable in the range 26.3 ... 29.3 V (in 0.1 V increments)

Load current I

Approx. 0.7 A (factory setting), 
adjustable to 0.35 A or 0.7 A
(charging is carried out with closed and open on/off circuit)
At a battery voltage of < 6 V (batteries defective), charging is not carried out as a protective measure.

Efficiency/heat loss

At U_{out rated}, I_{out rated} approx.

96.2%/14 W

With battery operation, approx.

96%/15 W

Protection and monitoring

Reverse polarity protection

Against polarity reversal on input voltage and batteries

Overload protection

In accordance with "dynamic current with overload" in normal operation (automatic restart attempts) or in battery mode (restart following return to normal operation)

Short-circuit protection

In accordance with "dynamic current with short-circuit" in normal operation (automatic restart attempts) or in battery mode (restart following return to normal operation). Built-in (not accessible) 16 A fuse (6 A and 15 A on DC UPS module) or 64 A fuse (40 A on DC UPS module).

Exhaustive discharge protection

Automatic shutdown when battery voltage falls below approx. 19 V.
At a battery voltage of < 6 V (batteries defective), charging is not carried out as a protective measure.

Monitoring
"Wire breakage in battery circuit"

Alarm signal if battery circuit not closed or if it opens during operation (cyclic check approximately every 20 s)

Monitoring
"Battery replacement required"

Alarm signal flashing at approx. 0.25 Hz repetition frequency (approx. 2 s alarm, approx. 2 no alarm, approx. 2 s alarm, etc.).
Check every 4 hours with 3 ohm load for 1 s if no buffer mode or switch-off has taken place within 4 hours.

Monitoring
"Battery charge status > 85%"

Indication whether batteries are charged to at least 85% of residual capacity still available depending on aging

Signaling⁴⁾

Normal operation

Green LED (OK) and isolated changeover contact
"24 V DC OK/Bat" at setting "24 V DC OK" ⁵⁾

Buffering or battery operation (battery supplies load alone or in addition to PS in the case of overload)

Yellow LED (Bat) and isolated changeover contact
"24 V DC OK/Bat" at setting "Bat" (neutral position)

Alarm (buffer not ready, or prewarning at and above < 20.4 V battery voltage)

Red LED (alarm) and isolated changeover contact at setting "Alarm" (= off position).

Causes of the buffer not being ready during normal operation can include: Off status or open on/off control circuit, battery module not connected, polarity reversal or defective battery (battery voltage < 18.5 V) or wire breakage between battery and UPS module. Signal is scanned and, thus, updated, every 20 s.

Causes of the buffer not being available during buffer operation can include: Battery voltage has dropped below 20.4 V DC (= prewarning before shutdown through exhaustive discharge protection) as well as shutdown of the battery due to overload, short-circuit, exhaustive discharge protection or expired backup time. The red LED then goes out.

"Battery replacement required"

Red LED (alarm) flashing at 0.25 Hz and floating changeover contact (alarm) switching at approx. 0.25 Hz

"Battery charge status > 85%"

Second green LED (Bat > 85%) and isolated NO contact closed (off position = open)

Optional port and software

Serial interface

Only for 6EP1 931-2.C31
Output of all alarm signals and receipt of the "Remote Timerstart" signal.
Technical design: PC-compatible. 8N1 send and receive, 9600 baud, 8 data bits, 1 stop bit, no parity bit.
Required connection to PC: 1 : 1 interconnected 9-pole sub D extension cable (connector/socket), only pin 2 (RXD), pin 3 (TDX) and pin 7 (RTS) are required.

USB interface

Only for6EP1 931-2.C42
Output of all signals and receipt of the "Remote Timerstart" signal.
Technical design: Specification 2.0 at full speed, i.e. 2 Mbit/s. Supplied with +5 V by DC UPS ("self-powered").
Required connection to PC: Commercially available 4-core shielded cable, 90 Ohm, max. 5 m, USB series "A" connector to PC and USB series "B" connector to DC UPS

Software

A software tool (executable under Windows 2000, Windows XP, Windows Vista and Windows 7) for reading out and processing the signals can be downloaded

http://www.siemens.de/sitop-usv

from the Internet at: This site also provides more information on the interface.

Control signals

On/off control signal

Buffering is terminated or the battery is disconnected from the output by opening the control circuit or by means of DIP switches on the device (DIP switch must be in "Off" position). All other functions are retained.

"Remote Timerstart" via serial interface or USB

Starts mains buffering for the set buffering time

Safety

Primary/secondary isolation

No

Safety class

Class III (ext. circuit and power-supply unit: SELV in accordance with EN 60950 required)

EMC

Emitted interference

Radio interference suppression according to EN 55022, Class B

Noise immunity

Noise immunity according to EN 61000-6-2

Environmental conditions

Ambient temperature during operation

-25 ... + 60°C with natural convection

Transport/storage temperature

‑40 ... + 85°C

Degree of protection (EN 60529)

IP20

Humidity class

Rated conditions in accordance with EN 60721, climate class 3K3 (relative humidity 5% ... 85% and absolute humidity 1 g/m³ ... 25 g/m³; no condensation)

Approvals

CE marking

Yes

UL/cUL (CSA) approval

cULus-listed (UL 508, CSA C22.2 No. 107.1) File E197259

Mechanics

Input connections 24 V DC

2 screw terminals for 1 ... 4 mm²/17 ... 11 AWG

Output connections 24 V DC

4 screw terminals for 1 ... 4 mm²/17 ... 11 AWG

Battery module connections 24 V DC

2 screw terminals for 1 ... 4 mm²/17 ... 11 AWG

Connections for control circuit and alarm signals

10 screw terminals for 0.5 ... 2.5 mm²/20 ... 13 AWG

Dimensions (W x H x D) in mm

50 x 125 x approx. 125

Weight, approx.

0.4 kg (with serial or USB interface: approx. 0.45 kg)

Mounting

Can be snapped onto standard mounting rail EN 60715 35x7.5/15