Honeywell SYA14 Series Manual page 607

IMPROPER EXTERNAL SAFETY RELAYS PERFORMANCE
•
Use three independent stop circuit safety relays K1, K2 and K3 with mechanically
linked contacts (such as GE CR120 BP Machine Tool Relay or Telemecanique CA3-
KN31BD3 or CA3-DN31BD relay) that prevent contact overlapping in the event of a welded
contact.
•
Always use the FSD monitoring loop to check correct operation of relays K1 and K2.
•
Always use the SSD monitoring loop to check correct operation of relay K3.
Failure to comply with these instructions could result in death or serious injury.
FUSES PROTECTION
The module supply input is protected by an internal fuse (which cannot be replaced by the
user) but all inputs must be protected by an external 0.5 A fuse connected on terminal 1
(+24 V POWER), and all outputs must be protected by an external 2.5A max. fuse
connected on terminal 32 (+24 V OUTPUT).
• The loads impedance allowed by the FF-SRM failsafe static outputs must be 55.2 Ω
minimum and 5kΩ maximum. The turn-on voltage must be greater than 5 V on resistive
loads or greater than 7 V on inductive loads.
•
The maximum cable length between the FF-SRM static outputs and the loads mainly
depends upon the loads resistance : the cable length must be L
•
If the FF-SRM module outputs are connected to safety relays with mechanically linked
contacts, the maximum cable length between the FF-SRM outputs and the relays is
greater than 100 m.
•
It is recommended to connect varistors in parallel with the FSDs relay coils.
•
Use of a RC circuit would prevent the module from operating.
IMPROPER PROTECTION INSTALLATION
• Never install varistor across the safety output of the muting module.
• Always install varistors across the coils of the external safety relays.
Failure to comply with these instructions could result in death or serious
injury.
107004-15 EN FR26 ROW 0899 Printed in France
≤ 50000 / R
cable load.
73