EtherPath User’s Guide
26
1. Transmit Timer
When in Timer Mode:
The time period for which data will be
stored in the buffer before being sent. Allowable values range from
1ms to 10,000ms (10 seconds). A commonly used value is 20 msec.
When in Idle Timeout Mode:
The time period this unit's port must
be idle (after receiving a character) before sending a block of data
via the Ethenet. This is used to keep incoming blocks of data intact.
It is useful for some protocols such as Modbus RTU. Its setting
depends upon the port speed, and should be several character times..
Allowable values range from 1ms to 10,000msec (10 seconds). A
typical value for a 9.6 Kbps port is about 3 msec.
M. Timer Mode
When set to 0
, the timer is a free-running clock and if there is data
in the buffer, an IP packet is transmitted every TIMER msec.
When set to 1
, the timer is a serial port idle time value. If there is
data in the buffer and the serial port has been idle for TIMER msec,
then an IP packet is transmitted.
2. Block Size
The
maximum
ethernet packet buffer size. The minimum value is 1
byte, the maximum 4096 bytes (4 K). Typical values are either in a
low range of 10-20 characters for polling applications or very large
in the range of 500 to 1500 for file transfer applications.
Normally, the timer triggers a packet transmission before the block
fills. If the buffer contains BLOCKSIZE characters, an IP packet is
transmitted regardless of the timer mode and settings.
3. Flow Control OFF Buffer Level
If the amount of data stored in the buffer reaches this point, and the
EtherPath is unable to transmit the data, then no further input will be
accepted.
