Product specifications

Appendix A Hardware Units Performance Data
3BSE036351-510 A 269
Communication Ports and Interfaces
For details on communication ports and interfaces, see Key Features on page 267
Battery
The memory content is backed up with an external battery unit (SB822). For backup
time, see Table 65.
Electro-magnetic Compatibility and Electrical Safety
PM891 meets the requirements specified in EMC Directive 2004/108/EEC.
For more information regarding electrical safety, see Appendix D, Directive
Considerations.
LED Indicators
See Table 20 on page 179.
Performance Data
The PM891 processor unit’s performance is approximately three times the
performance of PM864. In redundant configuration too, the execution performance
is approximately three times the performance of PM864.
The figures in Table 65 are valid if the batteries have been installed after a normal
CPU power-up, allowing for the memory backup function to be activated.
Table 65. Backup time for PM891
Source Back-up time for PM891
External battery SB822
Note: Recharge time for an
empty battery is
approximately 7 hours.
Minimum 33 hours when fully charged