8.8 Hard Wire Base Block (HWBB) Function
8-41
Operation
8
8.8.10
External Device Monitor (EDM
)
The external device monitor (EDM
) functions to monitor failures in the HWBB function. The relation of the
EDM
, /HWBB1, and /HWBB2 signals is shown below.
Failure Detection Signal for EDM
Signal
Detection of failures in the EDM
circuit can be checked using the following four status of the EDM
signal
in the table.
Connection Example
The connection example of EDM
signal is shown below.
Signal
Name
Logic
/HWBB1
ON
ON
OFF
OFF
/HWBB2
ON
OFF
ON
OFF
EDM
OFF
OFF
OFF
ON
For HWBB function signal connections, the input signal is the 0 V common and the output
signal is the source output. This is opposite to other signals described in this manual. To
avoid confusion, the ON and OFF status of signals for HWBB function are defined as follows:
ON: The state in which the relay contacts are closed or the transistor is ON and current
flows into the signal line.
OFF: The state in which the relay contacts are open or the transistor is OFF and no cur-
rent flows into the signal line.
Host controller
EDM
!
+
EDM
!
-
0 V
24-V power supply
SERVOPACK
