YASKAWA MP920 User Manual page 125

• The number of bits per character is the number of data bits (8 or 7) plus the number of
start bits (1), the number of stop bits (1 or 2), and the number of parity bits (1 or 0).
Processing Time of the Slave
• This is the time it takes a Slave to process the message once a query message has been
received from the Master, and to prepare a response message to the Master at the
MEMOBUS port.
• This time is related to the Machine Controller scan time, the number of items, such as
the coils or registers specified in the query message, and the number of items that can be
processed in one scan by the Machine Controller.
• With the MP920, all functions can be processed in one scan. Therefore, this time will be
the time required for one MP920 scan.
Delay Time of the Modem at the Slave
• This is the time it takes the modem at the Slave to return a clear to send (CTS) signal to
the Slave once the request to send (RTS) signal has been received from the Slave.
• With a Yaskawa modem, this time can largely be ignored because it is less than 5 ms.
• There is no delay time if a modem is not used.
Transmission Time for Response Message
• This is the time it takes the communications port of the Slave to transmit the query mes-
sage. In the same way as for the query message, the time can be calculated using the fol-
lowing equation:
No. of characters in query message × No. of bits per character × 1000
Transmisson time =
• The number of bits per character is the number of data bits (8 or 7) plus the number of
start bits (1), the number of stop bits (1 or 2), and the number of parity bits (1 or 0).
Processing Time by the Master for Response Message
• This is the time it takes a Master, such as a computer, to process the response message
once it has been received from the Slave.
• The time taken depends on the processing time of the Master.
• The time depends on the scan time of the Machine Controller, and is normally one or two
scans.
Baud rate
6-9
6.3 Module Specifications
6
(ms)