Toshiba TOSVERT VF-AS3 Instruction Manual page 17

4
Selecting communication protocol
Supported communication protocols are TOSHIBA inverter protocol and part of MODBUS-RTU
protocol.
Select the protocol in [F807: RS485 (1) protocol] or [F827: RS485 (2) protocol].
Communication
Title
No.
F807 0807
F827 0827
- The parameter change is reflected after reset, such as power-off.
4. 1 Reception frame completion process
To transmit/receive frame data, the frame synchronization scheme, where the start and end of a frame are
recognized, is defined with dataless time (blank time of 3.5 bytes).
After starting receiving, if data communication is not carried out in the current communication baud rate for
a time of 3.5 bytes or more (9600 bps: Approx. 4 ms or more, 19200: Approx. 2 ms or more, 38400 bps:
Approx. 1 ms or more), the reception is judged to be complete, and the frame information is analyzed. For
this reason, the frame transmission interval must be 3.5 bytes or more.
When continuously controlling multiple inverters on the same line individually, all inverters on the same line
receive not only transmission frames from the computer to the inverter but also reply frames from the
inverter to the computer. In this case, transmission from the computer to the next inverter requires a blank
time of 3.5 bytes or more after receiving a replay frame. Otherwise, a reply frame + a transmission frame
are analyzed as one frame, resulting in abnormal communication.
[Normal]
[Abnormal] Frame A, which is divided for transmission, cannot be received correctly when it has a blank
of 3.5 bytes or more.
VF-AS3
Parameter name
RS485 (1) protocol
RS485 (2) protocol
Frame A
Frame A
(1/2)
3.5 bytes
or more
Adjustment range
0: TOSHIBA
1: MODBUS
Frame B
Note) If the inverter is analyzing
3.5 bytes
Frame A, Frame B cannot
or more
be received.
Frame A
(2/2)
4-1
Default setting
0
0
Frame B
4. Selecting communication protocol
I
II
III
1
2
3
4
5
6
7
8
9
10
A1
A2
A3
A4
I
16
17
18