User`s manual

201
CHAPTER 6 CHANGING THE DATA COMMUNICATIONS MONITORING TIMES
6
6.3 Transmission Monitoring Time (timer 2) Setting
• Data communications using non procedure protocol or bidirectional protocol
• While waiting for the end of transmission of a message, the Q series C24 stores the error code to the data
transmission result storage area (buffer memory addresses 257H, 267H) for the target interface and
performs transmission processing abnormal completion. If message transmission was terminated midway,
the Q series C24 does not transmit the remaining data.
• If waiting for the end of transmission of a response message, the Q series C24 stores the error code to the
data receive result storage area (buffer memory addresses 258H, 268H) for the target device and turns on
the reception abnormal detection signal (X4, XB).
*1
When the receive data read complete, the Q series
C24 turns off the reception abnormal detection signal (X4, XB) and waits to receive the next command. If
transmission of the response message was terminated midway, the Q series C24 does not transmit the
remaining data.
*1 When communicating using bidirectional protocol, it stores the error code in the data receive result storage area for the
target interface. (The reception abnormal detection signal does not turn on.)
(2) Changing the transmission monitoring time (timer 2)
The transmission monitoring time (timer 2) is registered on the GX Configurator-SC's "Transmission control and
others system setting" screen.
The transmission monitoring time (timer 2) monitors the transmission termination time when the following states are
generated.
• When DTR/DSR signal control is used and the DR (DSR) signal is turned off ( Page 204, Section 7.1)
• When DC1/DC3 receive control is used and DC3 is received ( Page 206, Section 7.2)
• When the RS-232 interface CS (CTS) signal is turned off ( User's manual (Basic))
Remark
Criteria when changing the transmission monitoring time (time 2) setting
Find the transmission monitoring time (timer 2) time from the maximum delay time of external device message receive
processing or response message transmission processing and the transmission time/byte (t) and change the set value.
• Number of bytes transmitted/second (n) = Transmission rate/number of transmit bits/byte
• Transmission time/byte (t) = 1000 (ms)/number of bytes transmitted/s (n)
• Transmission monitoring time (timer 2) = (Maximum external device processing delay time) + (transmission
time/byte (t)  transmit byte count)100ms units truncated
Under the following conditions, the transmission monitoring time (timer 2) is set to 300ms
• Transmission rate: 9600 bps
• Number of transmit bits/byte: 11 (start bit: 1, data bits: 8, stop bits: 2)
• Maximum processing delay time: 200ms
• Transmit byte count: 3 bytes