Yaskawa Remote Display Controller LAN Node PCB for use with Microtrac DSD LAN - Manual (Page 6)

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5. RDU, keypad, and lockout switch.
The keypad allows the operator the
same functions as in D, above. The
lockout switch will enable or disable
the keypad. However, the two keys
assigned to the same functions as the
2 push buttons described in B and C,
above, (NAME and NEXT) may not be
disabled.
NODE/CHANNEL/MENU ITEMS
The PAC language defines a partic-
ular RDU displayable message by use of a
Node, a Channel, and a Menu Item number.
When concerning an RDC, the Node,
Channel, and the Menu Item number are
defined as follows:
NODE: RDC LAN Node Address
Switch Setting.
CHANNEL: 1 through 31 for RDU
number 1 through 31.
MENU ITEM #: The RDC keeps a menu
in its memory for each
RDU. Each menu may
have as many as 12
items. Each menu item is
referred to by its assigned
menu item number.
RDU LOCKOUT
Each RDU can be locked. If an RDU
is locked, then a keyoad connected to a
different RDU may not affect this RDU.
However, a push button or keypad
connected directly to this RDU may still
change the display or set a variable. The
RDC assumes that all of the RDUs are
unlocked unless specifically told otherwise
through a LAN message. The state of being
locked is determined by the PAC program-
mer and will be sent to the RDC via a LAN
message.
RDU MESSAGES
In the normal operating mode, each
RDU, under control from the RDC, will
display an alphanumeric legend and
numeric data. The legend may be up to 16
characters in length and is used to describe
the data. The numeric data will be limited
to 5-1/2 numeric digits plus sign.
The normal operating mode is devi-
ated from by use of a keyboard, a push
button, or one of several special events. The
messages the RDC will display on the RDU
and the special event that caused this are
listed and described as follows:
1. “Initializing”. When the RDC is
powered up, it makes a checksum
calculation of saved parameters and
the LAN Node ID, and compares it to a
saved checksum. If the checksums are
not equal, then the RDC assumes that
the memory was never initialized. To
show that this condition has occured,
the RDC will display “Initializing” on
each RDU until an active menu item is
found for the RDU.
2. “No Update” toggling with the legend.
This will occur when the RDC has not
received a LAN update message from
the source of the menu item within
the last 5 seconds. The LAN update
message contains the most current
value to show in the numeric display.
“No Update” is used to warn of the
possibility of bad data being shown
because of the lack of communication.
3. Cursor character toggling with the last
character in the legend. The cursor
character looks like a block. This
indicates that a keypad sequence has
started, and has not completed, and
that it affects this RDU.
RD 790-20