7
G.M. International ISM0112-10
D5291
- 10 A SIL 3 Relay Output Module for ND Load with ND or NE Relay condition
The proof test shall be performed to reveal dangerous faults which are undetected by diagnostic. This means that it is necessary to specify how dangerous undetected faults, which
have been noted during the FMEDA, can be revealed during proof test. The Proof test consists of the following steps:
Testing procedure at T-proof
Steps
Action
1
Bypass the safety-related PLC or take other appropriate action to avoid a false trip when removing the unit for test.
2
For the single channel, verify the input-to-output functionality:
1. For De-energized relays and open contacts, terminals “13”-“14”, the output load is normally de-energized when the input channel is off, while the activation of the
input channel energizes the load (safe state).
2. For Energized relays and open contacts, terminals “13”-“15”, the output load is normally de-energized when the input is supplied, while the shutdown of the input
channel energizes the load (safe state).
The channel functionality must be verified for a min to max input voltage change (21.6 to 27.6 Vdc).
In addition, the use of three relays for the single output channel, where the contacts are connected in parallel, requires to control the single coils by means of DIP-switch
(n°1, 3, 5) and to check the ohmic continuity of the contacts, as described in the following procedures.
1. Do not supply the input channel (terminals “1”-“2” or “3”-“4”) of the unit under test and verify that the ohmic continuity at the output contact terminals “13”-“14” is
absent (i.e. the parallel connection of the 3 NO contacts is open:
1
st
requisite is verified
). But this condition could also be true if all contacts are normally open
except one, which is blocked (for welding) into open position: this will be verified testing the channel when input is supplied (see
3
rd
requisite
). Instead, the presence
of ohmic continuity implies that at least one relay contact is blocked (for welding) into closed position: this could only be verified disassembling and individually testing
each relay.
2. Do not supply the input channel (terminals “1”-“2” or “3”-“4”) of the unit under test and verify that the ohmic continuity at the output contact terminals “13”-“15” is
present (i.e. the parallel connection of the 3 NC contacts is closed:
2
nd
requisite is verified
). But this condition could also be true if only one contact is closed and
others are blocked (for welding) into closed or open position: this will be verified testing the channel when input is supplied (see
4
th
requisite
). Instead, the absence
of ohmic continuity implies that all relay contacts are blocked (for welding) into open position.
3. Supply the input channel (terminals “1”-“2” or “3”-“4”) of the unit under test and verify that the ohmic continuity at the output contacts (terminals “13”-“14”) is present
(i.e. the parallel connection of the 3 NO contacts is closed:
3
rd
requisite is verified
). The absence of ohmic continuity implies that all relay contacts are blocked (for
welding) into open position. Instead, to verify if a single contact is blocked (for welding) into open position, use the DIP-switches (n°1, 3, 5) to short circuit each
possible couple among the 3 relay coils (starting with 1
st
& 2
nd
coils by DIP-switches n°1 & 3, then going with 1
st
& 3
rd
ones by DIP-switches n°1 & 5, and finally
proceeding with 2
nd
& 3
rd
ones by DIP-switches n°3 & 5), verifying that ohmic continuity is always present between terminals “13”-“14”. In this situation, the absence
of ohmic continuity implies that a relay contact (the only one with energized coil because the others are de-energized) is blocked (for welding) into open position.
4. Supply the input channel (terminals “1”-“2” or “3”-“4”) of the unit under test and verify that the ohmic continuity at the output contacts (terminals “13”-“15”) is absent
(i.e. the parallel connection of the 3 NC contacts is open:
4
th
requisite is verified
). The presence of ohmic continuity implies that at least one relay contact is
blocked (for welding) into closed position: this could only be verified after disassembling and individually testing each relay. Instead, to verify if a contact is blocked
(for welding) into open position, use internal DIP-switches (n°1, 3, 5) to put in short circuit one relay coil at a time (starting with the 1
st
coil by DIP-switch n°1, then
going on with the 2
nd
one by DIP-switch n°3, and finally proceeding with the 3
rd
one by DIP-switch n°5), verifying that the ohmic continuity is always present between
terminals “13”-“15”. In this situation, the absence of ohmic continuity implies that a relay contact (the only one with de-energized coil) is blocked (for welding) into open
position.
3
Remove the bypass from the safety-related PLC or restore normal operation inserting the unit.
This test reveals almost 99 % of all possible Dangerous Undetected failures in the relay module.
Warning
Operation
D5291S relay module is suitable for the switching of safety related circuits, providing isolation between the input and output contacts.
D5291S provides 1 SPDT contact for two different safety functions:
1) SIL 3 Safety Function for Normally De-Energized load (energized in fail safe state) is available at Terminal Blocks 13-14. The driving signal is normally low (0 Vdc),
the relay is normally de-energized, contact is open and load is de-energized. The safety function is met when the driving signal is high (24 Vdc), the relay is energized,
contact is closed and load is energized. At Terminal Blocks 13-15 is also available a service contact (for service load) with opposite (not SIL) function.
2) SIL 3 Safety Function for Normally De-Energized load (energized in fail safe state) is available at Terminal Blocks 13-15. The driving signal is normally high (24 Vdc),
the relay is normally energized, contact is open and load is de-energized. The safety function is met when the driving signal is low (0 Vdc), the relay is de-energized,
contact is closed and load is energized. At Terminal Blocks 13-14 is also available a service contact (for service load) with opposite (not SIL) function.
A “RELAY STATUS” yellow led lights when input is powered, showing that relay is energized.
Installation
D5291S is a relay output module housed in a plastic enclosure suitable for installation on T35 DIN-Rail according to EN50022 or on customized Termination Board.
D5291S unit can be mounted with any orientation over the entire ambient temperature range.
Electrical connection of conductors up to 2.5 mm² are accommodated by polarized plug-in removable screw terminal blocks which can be plugged in/out into a powered unit without
suffering or causing any damage
(for Zone 2 installations check the area to be nonhazardous before servicing).
The wiring cables have to be proportionate in base to the current and the length of the cable.
On the section “Function Diagram” and enclosure side a block diagram identifies all connections.
Identify the function and location of each connection terminal using the wiring diagram on the corresponding section, as an example (application for a single D5291S):
Connect positive input at terminal “1” and negative input at “2” (positive input at terminal “3” and negative input at “4” are provided for daisy chain connection to the next module).
Connect positive or AC load supply line to SPDT Output Common pole (terminal “13”).
Connect SIL 3 Normally De-Energized load between negative or AC load supply line and the terminal “14” (when relays are normally de-energized) or the terminal “15” (when relays are
normally energized), as previously shown in the Functional Safety applications.
Installation and wiring must be in accordance to the relevant national or international installation standards (e.g. IEC/EN60079-14 Electrical apparatus for explosive gas atmospheres
Part 14: Electrical installations in hazardous areas (other than mines)), make sure that conductors are well isolated from each other and do not produce any unintentional connection.
Connect SPST relay contacts checking the load rating to be within the contact maximum rating (10 A 250 Vac 2500 VA, 10 A 250 Vdc 300 W resistive load).
To prevent relay contacts from damaging, connect an external protection (fuse or similar), chosen according to the relay breaking capacity diagram on data sheet.
D5291S is an electrical apparatus installed into standard EN50022 T35 DIN-Rail located in Safe Area or Zone 2, Group IIC, Temperature Classification T4, Hazardous Area
(according to EN/IEC60079-15) within the specified operating temperature limits Tamb - 40 to +60 °C.
D5291S must be installed, operated and maintained only by qualified personnel, in accordance to the relevant national/international installation standards (e.g. IEC/EN60079-14
Electrical apparatus for explosive gas atmospheres - Part 14: Electrical installations in hazardous areas (other than mines)), following the established installation rules.
De-energize power source (turn off power supply voltage) before plug or unplug the terminal blocks when installed in Hazardous Area or unless area is known to be nonhazardous.
Warning: substitution of components may impair Intrinsic Safety and suitability for Zone 2.
Warning: de-energize main power source (turn off power supply voltage) and disconnect plug-in terminal blocks before opening the enclosure to avoid electrical shock
when connected to live hazardous potential
.
Explosion Hazard: to prevent ignition of flammable or combustible atmospheres, disconnect power before servicing or unless area is known to be nonhazardous.
Failure to properly installation or use of the equipment may risk to damage the unit or severe personal injury.
The unit cannot be repaired by the end user and must be returned to the manufacturer or his authorized representative. Any unauthorized modification must be avoided.
