Meggitt vibro-meter SpeedSys300 ODS301, User Manual

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Document reference MAODS301/E USER MANUAL
Edition 4 - May 2022 SpeedSys300 ODS301 overspeed detection system
3 - 9
Installation considerations
INSTALLATION OF A SPEEDSYS300 ODS301
Figure 3-3 provides an example of how to hardwire safety relay 1 of two SpeedSys300
ODS301 modules to obtain a 1oo2 voting logic structure.
Because a SpeedSys300 ODS301 module’s safety relays – relay 1 and relay 2 – are
double-pole single-throw (DPST) relays, there are several ways in which two modules can be
hardwired in series to obtain a 1oo2 voting logic structure.
Table 3-3 and Table 3-4 illustrate the two different ways in which a 1oo2 voting logic structure
can be implemented using the safety relay 1 of two SpeedSys300 ODS301 modules.
Table 3-3: 1oo2 – using safety relay 1 of SpeedSys300 ODS301 modules (1)
SpeedSys300 ODS301
modules
1oo2 to customer
#1 #2
B17 ↔ 1oo2 connection to customer circuit
B18 ↔ B17
B18 ↔ 1oo2 connection to customer circuit
Figure 3-3: 1oo2 – example using safety relay 1 of SpeedSys300 ODS301 modules