14
MITSUBISHI ELECTRIC AUTOMATION
3.2.2.1. Default I/O Assembly: Upon power-up, the FR-A5ND Option Unit
will default to Class 0x04 Output Instance 21 and Class 0x04 Input
Instance 71. See Section 6.3 for further information on DeviceNet Class 0x04
and changing the desired Output and Input Instances.
3.2.2.2. Polling Rate: Determination of the proper polling rate of the DeviceNet
master device is dependent upon the characteristics of the entire network. To
minimize potential conflicts and maximize system reliability, a minimum polling
rate interval of 30ms is suggested. The user may, at their discretion, adjust
this rate as network performance allows.
3.3.
Loss of Communications
In the default polled communication mode, the FR-A5ND DeviceNet Option
Unit will respond to loss of polling based upon configuration of the Watchdog
Timer Action (WDA) bits of parameter 345 (Pr345) as defined in Section 5.1
of this manual. The default value of these bits is decimal 0. Such loss of
polling may occur upon physical disconnection of network cabling, network
power loss, failure within the master, etc.
When the WDA bits of Pr345 are set to decimal 0, the VFD will continue to
execute the last command received until the communication time-out is
reached. This time out value is equal to 4 times the Expected Packet Rate
(EPR) as configured by the user. Once the FR-A5ND times out, the VFD will
generate an E.OP3 error and decelerate to a stop.
When the WDA bits of Pr345 are set to decimal 2, the VFD will continue to
execute the last command received until another command is issued. The
FR-A5ND will ignore the the communication loss, generate no error and au-
tomatically reset the connection when communication is restored.
4.
OPERATION
Operation of the A500(L) changes slightly when the FR-A5ND is installed.
These changes are described in the following paragraphs. Parameter defini-
tions including newly created parameters, as well as operation with the FR-
A5ND installed are described.
4.1
Operation Modes
4.1.1
PU operation mode
Control of the VFD is from the parameter unit (PU).
