Release 09/2019 Ver. 2.1

Installation Instructions: PRSU/2

PRSU/2 Safety Interface Controller
Installation Instructions
START INTERLOCK - When power is applied to the system,
the output relays cannot be energized until a reset signal has
been applied.

1. INTRODUCTION
Tapeswitch PRSU/2 control units are designed to be used withTapeswitch pressure sensitive sensors to form a complete safetysystem. Sensors may take the form of safety mats, sensing
edges, ribbon switches or bumpers. Full system installation
instructions are supplied with the sensors.

RESTART INTERLOCK - Once the sensor has been actuatedand the output relays have de-energized, they cannot beenergized again until a reset signal has been applied.
In auto reset mode the output relays will be energized whenever
power is applied to the system and the sensor is clear.

2. PRODUCT DESCRIPTION
The unit operates from a 24 Vac/dc supply. From this is derived
a current-limited 24 Vdc supply. The sensor and control circuit
operate from this current-limited supply. The unit is housed in aDIN rail mounting enclosure with 12 integral terminals. Thisunit is intended to be mounted in an existing electrical enclosureon the machine. This existing enclosure must be sealed to aminimum rating of IP54. See Figure 2 for unit dimensions.

In manual or auto reset mode, reset will be prevented if thesensor is actuated, if there is a fault in the reset input circuit, or
if the two output relays are in disparity.
The safety output contacts of the control unit are connected tothe machine primary control element(s) in such a way that ifeither of the safety output relays is de-energized then themachine will be brought to rest regardless of the state of theother relay.

3. SAFETY INTEGRITY
Tapeswitch PRSU/2 control units exceed the requirements ofsafety integrity Category 3, PLe (EN ISO 13849-1). The control
units are self-monitoring, which means that any faults in safety
critical components will be detected and will render the machine
inoperative until the fault is rectified.

NOTE: A machine primary control element or MPCE is definedas ‘an electrically controlled element which directly controls thenormal operating motion of a machine such that it is the last (intime) to operate when motion is initiated or arrested’.

However, the safety integrity of the system as a whole depends
on the safety integrity of the sensor used. See information
supplied with sensor for further details.

In addition, where the machine control system has two MPCE's,these devices can be monitored by connecting normally closed
auxiliary contacts from each MPCE in series with the reset
input. Disparity between the two MPCE's will prevent a reset.

4. PRINCIPLE OF OPERATIONThe control unit contains the power supply for the system, thesafety output relays and the reset circuit. A 24 Vdc power
supply is taken from the control unit to the switching elementsin the sensor(s), +ve to one conductor, -ve to the otherconductor, and back to the control unit where it supplies power
to the output relays. The output contacts of the safety relays areonly closed when the output relays are energized. When thesensor is actuated, the 24 Vdc power supply to the output relays
is shorted out causing them to de-energize. Furthermore, if thepower supply to the output relays is interrupted or shorted out
by a fault in the sensor wiring or in the switch elements, power
to the output relays will be lost, the relays will de-energize andthe output contacts will open.
Figure 1 – Principle of Operation

The unit provides a manual or auto reset function.
In manual reset mode the reset function provides start andrestart interlock functions as follows:

TAPESWITCH CORPORATION
100 Schmitt Boulevard
Farmingdale, New York 11735

Phone: 631-630-0442

1

Fax: 631-630-0454
www.tapeswitch.com

Release 09/2019 Ver. 2.1

Installation Instructions: PRSU/2

5. INSTALLATION

5.2 ELECTRICALWARNING

5.2.1 GENERALThe connections for the PRSU/2 control unit are shown inFigure 3. Crimped ferrules should be fitted on all strandedwires. It is recommended that electrical installation is performedin the order described below.

TAPESWITCH SAFETY SYSTEMS ARE DESIGNED TO
PROTECT OPERATORS WORKING AT OR NEARDANGEROUS MACHINES. THEY CAN ONLY PERFORM
THAT FUNCTION IF THEY ARE CORRECTLY FITTEDAND INTERFACED TO A SUITABLE MACHINE. EVERYEFFORT HAS BEEN MADE TO PROVIDE ACCURATE
AND COMPREHENSIVE INFORMATION, BUT IT IS THERESPONSIBILITY OF THE USER TO ENSURE THAT ALLPERSONS INVOLVED IN THE INSTALLATION OF THEPRODUCT HAVE THE KNOWLEDGE, TRAINING AND
EXPERIENCE NECESSARY, AND THAT THEY AREFULLY CONVERSANT WITH ALL LAWS, RULES,REGULATIONS AND CODES OF PRACTICE PERTAINING
TO THEIR TASK.

5.2.2 SENSOR CONNECTION
Connect the sensor cables to the control unit in accordance withTable 1, taking particular care that there are no stray strands
which could cause a short between adjacent terminals.
5.2.3 POWER CONNECTION
Connect +24V to terminal A1 and OV to terminal A2 as shownin figure 3. The maximum power consumption is 2.5VA.

5.1 MECHANICAL

5.2.4 RESET INPUT CONNECTION

5.1.1 GENERAL

For auto reset mode connect a link across terminals S33 & S34
as shown in fig.4.

The PRSU/2 control units should be mounted in the machine
control unit on standard ‘top hat’ terminal rail type DIN EN 50
022-35. The machine control unit must provide sealing to IP54
according to IEC 529. The dimensions of the unit are shown inFigure 2.

For manual reset mode connect a normally open switch acrossterminals S33 & S34 as shown in fig.5.

The exact cabling requirements are at the discretion of theinstaller and depend to a large extent on the siting of the variouscontrol system elements. Generally it is recommended that highvoltage cables are routed away from low voltage cables.

If the machine has two MPCEs, a pair of normally closed
auxiliary contacts from each MPCE can be connected in series
with the reset input as shown in Figure 6. This provides crossmonitoring of the MPCEs such that if they are in disparity due
to a fault, reset will be prevented until the fault is rectified.

5.1.2. RESET INPUT DEVICE

5.2.5 SAFETY OUTPUT CONNECTION

A momentary action, normally open switch, preferably a 22mm
industrial pushbutton, should be used to provide the reset input.
The switch should be housed in a suitable enclosure and should
be mounted in such a position that it is safe from damage by
passing traffic and such that the person operating the switch can
see all of the dangerous area.

Two normally open safety outputs are provided. In low tomedium risk applications the machine is normally provided witha single MPCE. In such cases both safety outputs should beconnected in series with the MPCE coil as shown in Figure 7. If
the machine is fitted with two MPCEs, one safety output
should be connected in series with each MPCE coil, as shownin Figure 8.
To protect the contacts of the safety output relays from theeffects of switching inductive loads, it is recommended that arc
suppressors should be fitted in parallel with the MPCE coils asshown Figures 7 and 8. Arc suppressors must not be fitted
across the safety relay contacts.
To protect against the possibility of both safety outputs welding
in, due to an overcurrent fault in the machine circuit, 2A fusesshould be fitted in series with the MPCE coils as shown inFigures 7 and 8. This limits the current through the safety output
contacts to well below that which could cause the contacts toweld.

Figure 2

TAPESWITCH CORPORATION
100 Schmitt Boulevard
Farmingdale, New York 11735

Phone: 631-630-0442

2Fax: 631-630-0454
www.tapeswitch.com

Release 09/2019 Ver. 2.1

Installation Instructions: PRSU/2Figure 3

Figure 4 – Auto Reset

Table 1

5.3 INITIAL CHECKING
The system can be checked at this point as follows:(a) Check that the sensor is clear.
Figure 5 – Manual Reset(b) Apply power to the control unit. DO NOT APPLY POWER
TO THE MPCEs. The POWER ON indicator should be lit, theCHANNEL 1 and CHANNEL 2 indicators should be off.
(c) Activate the reset button. The CHANNEL 1 and CHANNEL
2 indicators should illuminate.
(d ) Actuate the sensor. The CHANNEL 1 and CHANNEL 2indicators should go off.
If the system operates as described above, the installation canbe completed. Before putting the machine into use the complete
system should be commissioned as described in the sensor
manual. If the safety system does not operate as describedabove, refer to the sensor manual for the fault finding
procedure.

Figure 6 – Cross-Monitoring of MPCEs
TAPESWITCH CORPORATION
100 Schmitt Boulevard
Farmingdale, New York 11735

Phone: 631-630-0442

3Fax: 631-630-0454
www.tapeswitch.com

Release 09/2019 Ver. 2.1

Installation Instructions: PRSU/2

Figure 7 – Safety output connection (single MPCE)

Table 2

Figure 8 – Safety output connection (two MPCEs)

6. TECHNICAL SPECIFICATIONTAPESWITCH CORPORATION
100 Schmitt Boulevard
Farmingdale, New York 11735

Phone: 631-630-0442

4

Fax: 631-630-0454
www.tapeswitch.com