3S7505PG520A6 GE Power module Brand new

Backplane Comm window Setting and 

Genius redundancy

When using Genius Redundancy, do not set the backplane 

communications window timer to 0. Also be sure to allow enough time 

for the backplane communications window to run when using Constant 

Sweep mode. Ample backplane communications window time must be 

available for the GBCs to exchange information about Genius devices 

that are lost and added.

Expansion rack ID Series 90-70 expansion racks are shipped with the rack ID strapped 

for rack 0 (the main rack). If the rack jumper is not changed the CPU 

will not recognize the rack at all and may not properly identify the 

error.

Expansion rack cable Connection and disconnection of an expansion rack cable while the 

CPU is running should not be attempted. This will cause the RX7i to 

go to the STOP/HALT state.

Expansion rack power Expansion racks should be powered up at the same time the main 

rack is powered up or they should be powered up after the main rack 

has completed its power up initialization. Do not power up an 

expansion rack while the CPU is running power-up diagnostics.

Timer operation Care should be taken when timers (ONDTR, TMR, and OFDTR) are 

used in program blocks that are NOT called every sweep. The timers 

accumulate time across calls to the sub-block unless they are reset. 

This means that they function like timers operating in a program with a 

much slower sweep than the timers in the main program block. For 

program blocks that are inactive for large periods of time, the timers 

should be programmed in such a manner as to account for this catch 

up feature.

Related to this are timers that are skipped because of the use of the 

JUMP instruction. Timers that are skipped will NOT catch up and will 

therefore not accumulate time in the same manner as if they were 

executed every sweep.

Constant sweep Constant Sweep time, when used, should be set at least 10 

milliseconds greater than the normal sweep time to avoid any oversweep conditions when monitoring or performing on-line changes with 

the programmer. Window completion faults will occur if the constant 

sweep setting is not high enough. A consistent over sweep condition 

can cause the programmer to lose communications with the RX7i.