Microhard Systems IP920, Operating Manual, Page: 40 / 73

30 IP920 Operating Manual: Chapter 4 Configuration
Flow Control:
To make serial port data communication reliably, hardware
handshaking can be used. If a serial device doesn’t support hardware
handshaking, flow control should be set to “None”. When CTS Framing is
selected, IP920 uses CTS signal to gate output data on serial port. The
following figure shows timing diagram of CTS output data framing.
Figure 14 CTS Output Data Framing
Pre-Data Delay (ms): See Figure 14.
Post-Data Delay (ms):
See Figure 14.
Data Mode:
defines serial data output framing. Serial port service adds
time gap between data frames to comply with MODBUS protocol when
data mode is set to MODBUS. At least a 3.5 character time gap is inserted.
This value can be modified by the Character Timeout setting. On the other
hand, the serial server will output serial data to the serial port as quick as
possible in transparent mode; no delays will be inserted between frames.
CTS
RXD
Data leaving IP920
Pre-Data
Delay (ms)
Post-Data
Delay (ms)