Toshiba MDB-100 Manual De Usuario

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 16 
data will be the data obtained from registers 0xFE03, 0xFE04, 0xFE06, and 0xFD00 
(in that order). 
 
Note that the settings of the programmable address registers (0x6000 
 0x601F) are 
stored in the MDB-100’s nonvolatile EEPROM.  Therefore, do not write to any of 
these registers more than 100,000 times.  Typically, these registers would only be 
written to once, when the interface and Modbus network are first commissioned.  
When the programmable pointer registers are modified, the changes are made 
effective in the MDB-100 immediately (the MDB-100 does not need to be reset for the 
changed values to take effect). 
 
 
9.3  Loss of Communications Timer Function 
A configurable "loss of communications" (network watchdog) timer function is 
provided, which can detect communication losses and perform certain actions if a 
valid packet is not received and processed within a set time period. 
 
MDB-100 register 0x6100 sets the loss of communication time value (adjustable from 
100ms to 60.000s in 1ms increments, factory setting = 10.000s).  If a valid 
(exception-free) reception-response or exception-free broadcast does not take place 
within this time limit, the timer will expire.  If the timer expires, 5 possible actions can 
occur for each connected drive, as set by the value of registers 0x6101 and 0xE101  
(loss of communications action for drive A and drive B, respectively): 
 
Register 
0x6101 / 0xE101 
Setting 
Action Taken Upon Timeout 
0 (default) 
No action: ignore timeout 
1 Decelerated 
stop 
2 Coast 
stop 
3 Trip 
“E” (emergency off) 
Run a preset speed 
 
When a network timeout is detected, the timeout action is performed.  When 
communications are once again reestablished, the timer function is automatically 
reset and will once again begin to monitor network receptions.  However, any actions 
performed as a result of the timeout occurring will not be reversed by the MDB-100 
once communications are reestablished; the Modbus master’s application must 
explicitly modify the affected conditions to fully return the drive to its previous state. 
 
Setting 0 is the default setting; when a communications timeout occurs, no action will 
be taken. 
 
For setting 1 (decelerated stop), the drive will stop in a controlled manner if it was 
running.  This action clears bit #10 in the selected drive’s communication command 
bit structure (register 0x7A00 / 0xFA00 - also the same data as write-only coil #10 / 
#26).  Note that the “communication command valid” bit of register 0x7A00 / 0xFA00 
(bit #15 of each register, or write-only coil #15 / #31) must already be set by the 
master application for this timeout action to control the drive.