TOSHIBA VF-AS3 inverter RS485 communication function

Example: Point 1 (0% → 10Hz), point 2 (100% → 80Hz), master station instruction 50% → slave station frequency=10+(50-0) × (80-10)/(100-0)=45Hz.

3. Fault handling

Main station tripping: The main station sends the command s (73H), and the slave station sets the action according to [F806]/[F826] (0=0Hz, 1=continue operation, 2=emergency stop).

Communication interruption: The communication timeout (Err5) is triggered by the slave station, and the action (such as tripping) is set according to [F824]. The master station is not affected (the status needs to be fed back through the FL fault terminal of the slave station).

Detailed explanation of communication related parameters

The communication function of the frequency converter requires the configuration of a "communication parameter group" (F8xx series), and some parameters need to be reset after power failure to take effect. The key parameters are as follows:

Parameter number, parameter name, function description, adjustment range, default value, effective method

F800/F820 RS485 baud rate setting communication rate 0=9600bps, 1=19200bps, 2=38400bps 1 (19200bps) power off reset

F801/F821 RS485 checksum setting verification method 0=no verification, 1=even verification, 2=odd verification 1 (even verification) power off reset

F802 frequency converter number setting bus address 0-247 0 immediately

F803/F823 communication timeout setting timeout detection duration 0.0 (disabled), 0.1-100.0s 0.0s immediately

F804/F824 timeout operation timeout device action 1=continue running, 4=trip immediately, 6=trip immediately after deceleration, 1=trip immediately

F806/F826 master-slave communication mode setting master-slave role master station: 3-6; Slave: 0-20 (Slave) Power off reset

F807/F827 communication protocol selection Toshiba/MODBUS 0=Toshiba protocol, 1=MODBUS-RTU 0 power-off reset

F829 RS485 (2) wiring type 2-wire/4-wire switching 0=2-wire system, 1=4-wire system 0 immediately

F830 MODBUS continuous address direct read whether to skip empty parameter 0=skip, 1=do not skip 0 immediately

F870/F871 block write parameter 1/2 setting block communication write parameter 0=disabled, 1=FA00 (run command), etc. 0 power off reset

F875-F879 block read parameters 1-5 set block communication read parameters 0=disabled, 1=FD01 (status), etc. 0 power off reset

Troubleshooting and Appendix

1. Common faults and solutions

Troubleshooting steps for possible causes of fault phenomena

Communication unresponsive 1. Baud rate/checksum/protocol mismatch; 2. Wiring error (A+/B - reversed connection, SG not connected); 3. The frequency converter number does not match; 4. Uninnected terminal/pull-up/pull-down resistor 1. Unify all device parameters (such as 19200bps+even parity+Toshiba protocol); 2. Check the A+/B - wiring to ensure SG interconnection; 3. Confirm that INV-NO is consistent with [F802]; 4. Install 120 Ω terminal resistors (at both ends) and 510 Ω pull-up and pull-down resistors (at all nodes)

Err5 tripped (communication timeout) 1. Communication cable disconnected; 2. The main station did not send data; 3. The timeout period is too short; 4. The slave station did not receive the command from the master station. 1. Check the continuity of the cable; 2. Confirm that the main station sends commands normally (such as once per second); 3. Increase [F823] (e.g. set to 1.0s); 4. Verify the master and slave station interfaces (if both are using Connector2)

Write parameter error (N0000): 1. During operation, write prohibited parameters (such as maximum frequency [FH]); 2. Parameter locking ([F700]=2/4); 3. Password setting ([F738]) 1. Write prohibition parameter after shutdown; 2. Set [F700]=0 (unlock); 3. Clear the [F738] password

Data transmission error (garbled code) 1. Electromagnetic interference (parallel wiring with the main circuit); 2. Cable over distance; 3. The terminal resistor is not connected. 1. Adjust the cable routing and keep it away from the main circuit; 2. Shorten cables or add repeaters; 3. Connect a 120 Ω terminal resistor

2. Appendix Key Information

(1) Response time calculation

Total response time=data communication time+frequency converter processing time (maximum 10ms).

Data communication time=(bytes x bits)/baud rate, bits=1 (start bit)+8 (data bit)+1 (check bit)+2 (stop bit)=12 bits (default).

Example: 19200bps, 8-byte command → communication time=(8 × 12)/19200=5ms, total response time ≈ 15ms.

(2) Corresponding Table of Inverter Models and FB05 Parameters

[FB05] The parameter is used to identify the frequency converter model, and some common models correspond to the following relationships:

Inverter model, voltage level, power FB05 (decimal), FB05 (hexadecimal)

VFAS3-2037P 200V 3.7kW 9 9

VFAS3-4055PC 400V 5.5kW 42 2A

VFAS3-4220PCE 400V（IP55） 22kW 147 93

(3) ASCII code table

Provide JIS X0201 ASCII code mapping, such as "0"=30H, "A"=41H, "d"=64H, for ASCII mode command writing and data parsing.