Yokogawa Button Operated MV2000 - Manual (Page 50)

M-4662 2-36
Resuming Command Transmission
Using the front panel keys, you can resume command transmission to a server device
whose communication is stopped (red status lamp).
1. Using the up and down arrow keys, select the command assigned to the server
device that you want to resume transmission. The message “Push [right arrow] key to
refresh” appears.
2. Press the right arrow key. The MV will transmit a command to the specified server.
Data When Communication Is Stopped and during Connection Retrials
If command transmission stops such as when the connection is disconnected, the
status lamp will turn orange or red, and the communication input data and external input
channel data will be error data. For computation channels, the MV displays “+OVER” or
“–OVER” according to the settings. The MV displays “******” for external input channels.
Data Dropout
A data dropout occurs when the commands 1 to 16 do not complete within the read cycle
(see appendix 2). When a data dropout occurs, the communication input data is held at
the previous value. The Modbus operating status display shows a message indicating
that a data dropout occurred. If this happens, take measures such as making the read
cycle longer or reducing the number of commands. Be sure to confirm that no data
dropout occurs on the Modbus status log display.
2.9 Reading/Writing Data on Another Device from the MV via Modbus