6. CONNECTION OF I/O UNITS TO
3) DO (output signal) alarm detection
The DO driver of the FSSB I/O module is capable of detecting an
excess load current and measuring its own temperature. If an accident,
such as connecting the cable to ground, causes an abnormal increase
in the load current, or if the DO driver becomes abnormally hot for
some reason, a protection circuit, which is provided for each DO driver
(1 byte), is activated, which keeps the DO signal for the relevant 1 byte
in the OFF state until the cause of the problem is eliminated. Even if
this occurs, the Power Mate i and the unit do not generate an alarm but
instead continue operating. The above R area identifies which unit has
detected an alarm. Bit value “1” indicates that the corresponding unit
has detected an alarm. Thus, which unit has detected a DO error can
be checked on the DGN screen of the Power Mate. Performing DO
alarm processing in advance by using Ladder ensures safety and
assists in fault investigation and recovery.
If the ladder program does not perform DO alarm
processing in advance, the Power Mate cannot detect an
error in the DO driver.
4) Timing at which the FSSB I/O module data becomes valid
The I/O unit connected to an FSSB I/O module does not start data
transfer unless both the PMC and the servo are started. (There is a time
delay before the data becomes valid.) It is necessary to determine
whether the data from the FSSB I/O module is valid using the FSSB
I/O module data enable (FSSB) parameter, shown below, before using
#6 #5 #4 #3 #2 #1 #0
FSSB 0 : The data from the FSSB I/O module is invalid.
1 : The data from the FSSB I/O module is valid.
5) Additional explanation
1 The addresses in the R area for each group, DIs, and DOs must be
2 The R area may be used for other units. The addresses for the units
must also be unique.
3 Data simultaneity is assured in units of one byte, starting with the