PAGE 19 12-5-97 CHAPTER 3: OPERATION
3.2.4
The Option card writes to the “option” function code P00 to indicate the specific error whenever
a network fault occurs. If network faults occur frequently as part of normal operation, this feature should
be disabled to save the Inverter’s EEPROM memory. To disable this feature, temporarily set the Option
card to manual mode and set the value in P00 to 255 with the keypad. Should a network error occur later
with this code disabled, it can be re-enabled to display the error as long as the network error condition still
exists. To re-enable, temporarily set the mode to manual and use the keypad to set P00 to zero. Next,
set the mode back to automatic to re-generate the error code which will appear in the P00 function code
value.
3.3 Manual/Automatic Mode
3.3.1
Two modes of operation are provided (manual/automatic) by the HE300DNT100,
which are
controllable by a set of contacts on the Option card. Automatic mode allows control of the Inverter over
the network and Manual mode provides local control of the Inverter through the terminal board and
keypad.
3.3.2
The mode can be changed during normal operation; however, precautions should be observed
to prevent adverse motor changes. Both the Option board and the Inverter maintain a separate set
of control parameters. The set that is selected is dependent on the current mode. Additionally, if
the selected mode is such that a set of control parameters may be not directly controlling the Inverter,
they may still be changed and stored in memory. For example, DeviceNet
Poll message bytes 0 and 1
are written to a pseudo-terminal block word, which in effect emulates contact closures on the Inverter’s
terminal when the unit is in automatic mode. In manual mode, the pseudo-terminal contact word can still
be changed with a DeviceNet
Poll message. It will be maintained and take effect once switched back to
manual (assuming Poll connection is maintained).
3.3.3
While the Inverter’s function parameters are always readable from either the keypad or the
DeviceNet
Poll message, the current mode affects which has write access. Table 3.1 summarizes
access to the control and function parameter in the two modes:
Table 3-1. Mode selection parameter access.
Manual
Automatic
Terminal Board
Active
Inactive
Network Pseudo Terminal*
Inactive (memory)
Active
Local Freq. Control**
Active
Inactive (memory)
Network Freq. Control
Inactive(memory)
Active
Keypad Parameter Access
Read + Write
Read Only
Network Parameter Access
Read Only
Read + Write
* Keypad “Start” button can be assigned for final start control even under network control.
The Keypad “Stop” button functions as an emergency stop even under network control.
** Local frequency control can be assigned to either the keypad or terminal analog input.
3.3.4
Both the local frequency display and the Poll message response (Bytes 2,3) will contain the
current drive frequency regardless of the mode.
3.3.5
While in automatic mode, the Option card monitors the state of the DeviceNet
Poll connection.
Should the connection fail (lost communications with the master), the Option card will take the action as
specified by the Loss-of-Network parameter which is described later in this chapter. Should
communications be lost with the Option card, the card can be placed in manual mode to gain local control
of the drive.
