Jokab Safety BT51, BT51T Catalog Page

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Safety relay/expansion relay

BT51(T)

Approvals:

TÜV Nord

Safety relay for:

Emergency stop

Interlocked hatch

Expansion of Pluto

Features:

Single and “dual” channel

Test/"reset" input

Width 22.5 mm

LED indication

Safety relay/expansion relay to Pluto

The BT51 is designed to connect safety devices, such as
emergency stops, directly in the voltage supply circuit to
the relay. Despite a maximum built-in width of 22.5 mm the
relay is very powerful.
With 4 NO safety outputs, test input and complete in­ternal supervising, the BT51 is quite unique. In addition
you can order delayed outputs (BT51T).
In order for the safety outputs to close, the supply volt­age, e.g. by means of an emergency stop button, must be
connected to A1 and A2 and the test input closed. After
actuation of the relay the test input can be opened again.
The test input is intended to supervise that contactors
or valves have dropped/returned before a new start can
be permitted.The test input can also be used for starting
and the start button can be supervised (see connection
example on next page).

More outputs

By connecting BT51 to a safety relay/PLC it is easy to
increase the number of safe outputs. This means that an
unlimited number of dangerous machine operations and
functions can be stopped from one safety relay/PLC.

4 NO relay outputs

Supply 24 VDC

Quick release connector
blocks

BT51 - Additional power
terminals

BT51T - One changeover
relay with a double informa­tion output (Y14)

BT51T

Delay times selectable from
0 - 1.5 s

Safety level

BT50 have an internal redundant and monitored safety
function. Power failure, internal component faults or exter­nal interference cannot result in dangerous functions.
Input via A1 only is not protected from short circuiting,
and therefore installation is critical for the safety level to be
achieved. To achieve a higher safety level a screened ca­ble can be used and/or connection made to both A1 and
A2 (see example overleaf).

Regulations and standards

The BT51 is designed and approved in accordance with
appropriate directives and standards. See technical data.

Connection examples

For examples of how our safety relays can solve various safety
problems, please see the chapter “Connection examples”.

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Technical data – BT51(T)

1 2 0

84

2 2 , 5

Manufacturer ABB AB/Jokab Safety, Sweden
Article number/Ordering data

BT 51 2TLJ010033R2000
BT 51T 2TLJ010033R3000

Colour Black and beige
Operational voltage 24 VDC + 15%/-25%
Power consumption 1,4 W/1,8 W
Relay Outputs 4 NO
Max. switching capacity

Resistive load AC 6A/250 VAC/1500 VA
Inductive load AC AC15 240VAC 2A
Resistive load DC 6A/24 VD C/150 W
Inductive load DC DC13 24VDC 1A

Max. res. load total switching
capacity: 12 A distributed on all contacts

Min. load 10mA /10 V (if load on contact has

Contact material Ag + Au flash
Fuses Output (External) 5A gL/gG
Conditional short-circuit current

(1 kA) 6A gG
Max Input Wire res. at nom.

voltage 200 Ohms
Response time at deactivation <20 ms or delayed max 1500 ms

Terminals (Max. screw torque 1 Nm)

Single strand: 2x1.5 mm
Conductor with socket contact: 2x1mm

not exceeded 100 mA

(B T51T)

2

2

Mounting 35 mm DIN-rail
Protection class enclosure/

terminals IP 40/20 IEC 60529
Impulse Withstand Voltage 2.5kV

Pollution Degree 2
Operating temperature range -10°C to +55°C (with no icing or

Operating humidity range
LED indication Electrical Supply, Relay and X4
Weight 200 g
Performance (max.)

Functional test: The relays must be
cycled at least once a year.

Conformity 2006/42 /EC, 2006/95/EC,

condensation)

35% to 85%

Category 4/PL e (EN ISO 13849­1:2 008)
SIL 3 (EN 62061:2005)
PFHd 1.63E-08

2004/108/EC
EN 954-1:1996, EN 62061:2005
EN ISO 13849-1:2008

Connector blocks are detachable
(without cables having to be disconnected)

1

2

3

4

5

Technical description – BT51(T)

Supervision circuit

When supply voltage is connected to A1
and A2, relays K1 and K2 are activated. K1
and K2 drop if the supply voltage is discon­nected. Both relays K1 and K2 must drop for
them to be activated again. Another require­ment is that the test circuit, A1 - X4, must
be closed for the outputs to be activated.
Thereafter A1 - X4 can either be open or
constantly closed.

The supervising circuit ensures that both
K1 and K2 have dropped before they can
be reactivated. The stop function complies
with the requirement that a component fault

Electrical connection – BT51(T)

or external interference cannot lead to a
dangerous function.

The safety outputs consist of contacts
from K1 and K2 connected internally in
series across terminals 13 - 14, 23 - 24, 33

- 34 and 43 - 44. These contacts are used
to cut the power to components which stop
or prevent hazardous movements/functions.
It is recommended that all switched loads
are adequately suppressed and/or fused in
order to provide additional protection for the
safety contacts.

BT51T - Info. output

BT51T - Delay times

A2 T1 T2 A2 T1 T2

0 s

0.5 s

1.0 s

1.5 s

Max load
250 mA

6

7

8

9

10

*

Emergency stop with reset when emergency
button returns.

*

Emergency stop with dual connection direct
to the supply voltage.

* BT51 has additional power terminals A1 and A2.

*

Hatch with automatic reset. BT51 as emergency stop and control

relay with Start and Stop function.

LOAD

A1 X4

Controlled monitoring of external contac­tor, relay, valve or ABB Jokab Safety’s
expansion relays.

Monitoring to ensure that the On but­ton is not stuck in pressed position. A
short circuit over the closing contact is
not monitored.

A1 X4

11

12

13

14