6 Modbus and PNP/NPN conversion
Modbus
Communication specifications
| Item | Content | |
| Communication protocol | Modbus protocol | |
| Standard specifications | Modbus-RTU slave station communication protocol | |
| Maximum connections | 247 | |
| Topological structure | Bus type | |
| Slave station function | Number of messages that can be received and requested at the same time | 1 |
Hardware configuration
| Terminal identification | Terminal name | Function description | Jumper/dialing position |
| J5 | 485 communication terminal resistance setting jumper | Match terminal resistance |
|
Modbus communication port of this product is located on the control panel, as shown in the following figure:
RS485 Connection Topology
RS485 bus connection topology is shown in the following figure. 485 bus is recommended to use shielded twisted pair (STP), 485+, 485-: Adopt twisted pair to connect; Only 120 Ω terminal matching resistors are connected at both ends of the bus to prevent signal reflection; All node 485 signal grounds are connected together; Connect 128 nodes at most, and the distance between branches of each node should be less than 3m.
Multi-node connection mode
When the number of nodes is large, 485 bus must be daisy chain connection. If branch connection is needed, the branch length from bus to node had better be short. It is recommended that it should not exceed 3m. Star connection should be forbidden. The diagram of common bus structure is as follows:
Figure1 Daisy chain connection
Figure2 Branch connection
Figure3 Star connection (Forbidden)
Transmission distance
The maximum number of nodes and transmission distance supported by our standard RS485 circuit at different rates are shown in the following table.
The communication distance between the inverter and other devices should not exceed 200 meters, if it exceeds two hundred meters it may cause unstable communication. If the communication distance exceeds 200 meters, the following measures need to be included:
- Communication cable：Adopt twisted pair to connect
- anti-interference magnetic ring
| Transmission distance (m) | Rate (kbps) | Number of nodes | Wire diameter |
| 100 | 115.2 | 128 | AWG26 |
| 1000 | 19.2 | 128 | AWG26 |
PNP/NPN
VM series
NPN/PNP switching has been added to the VM series machines, enabling fast switching between the two modes.
The NPN/PNP mode can be switched manually at the illustration to realize the compatibility of external signals. Where the upper two pins are shorted for NPN, the lower two pins are shorted for PNP mode.
Product model
0.75~2.2(KW)
4~7.5(KW)
VM PNP mode
VM NPN mode
VB series
The control signals of VB series products are compatible with both NPN and PNP signal types.
| Low-power model | High-power model | |
|---|---|---|
| Adapted power | 220V：0.75-2.2kW 380V：0.75-7.5kW | 380V：11-400kW |
| NPN signal | Default Compatible | Default Compatible |
| PNP signal | Add expansion board | Changing OP terminal |
Add an expansion card for PNP signal compatibility for small control board.
Introduce of expansion module
(1)Name：PNP signal compatible expansion board
(2)Picture：
(3)Application Principle：VB 0.75kW-7.5kW PNP mode
VB 0.75kW-7.5kW NPN mode
VB 11kW-400kW PNP mode
VB 11kW-400kW NPN mode
VB wiring instructions for common control methods
（1）Two-wire type 1 mode controls forward and reverse rotation
| Correlation parameter | Name | Set value | Function description |
| F5.16 | Terminal command mode | 0 | Two-wire type 1 |
| F5.00 | DI1 Terminal Function Selected | 1 | Forward running（ FWD） |
| F5.01 | DI2 Terminal Function Selected | 2 | Reverses run（ REV） |
Two-wire mode 1: This mode is the most commonly used two-wire mode. For example, the DI1 terminal is assigned the forward running function, and the DI2 terminal is assigned the reverse running function. Connect the forward running switch to DI1 terminal and the reverse running switch to DI2 terminal.
Refer to the following table for running commands corresponding to switching signals:
| K1 | K2 | Run command |
| 0 | 0 | STOP |
| 1 | 1 | STOP |
| 1 | 0 | Forward running |
| 0 | 1 | Reverses running |
（2）Two-wire type 2 mode controls forward and reverse rotation
| Correlation parameter | Name | Set value | Function description |
| F5.16 | Terminal command mode | 1 | Two-wire type 2 |
| F5.00 | DI1 Terminal Function Selected | 1 | Run command |
| F5.01 | DI2 Terminal Function Selected | 2 | Forward and reverse direction |
Two-wire mode 2:In this mode,the DI1 terminal assigns the command function, and the DI2 terminal assigns the forward and reverse direction function.
Refer to the following table for running commands corresponding to switching signals:
| K1 | K2 | Run command |
| 0 | 0 | STOP |
| 0 | 1 | STOP |
| 1 | 0 | Forward running |
| 1 | 1 | Reverses running |
（3）Three-wire type 1 mode controls forward and reverse rotation
| Correlation parameter | Name | Set value | Function description |
| F5.16 | Terminal command mode | 2 | Three-wire type 1 |
| F5.00 | DI1 Terminal Function Selected | 1 | Forward running（ FWD） |
| F5.01 | DI2 Terminal Function Selected | 2 | Reverses run（ REV） |
| F5.02 | DI3 Terminal Function Selected | 3 | Three-wire operation control |
Three-wire control mode 1: In this mode,the DI3 terminal allocates the three-wire operation control function, the DI1 terminal allocates the forward operation function, and the DI2 terminal allocates the reverse operation function. This control mode requires the frequency converter to use an external button as the start-stop switch of the inverter. Connect the start-stop button to DI3 terminal, the forward running button to DI1 terminal, and the reverse running button to DI2 terminal.
Among them: SB1 forward button; SB2 reverse button; SB3 Stop button;
（4）Three-wire type 2 mode controls forward and reverse rotation
| Correlation parameter | Name | Set value | Function description |
| F5.16 | Terminal command mode | 3 | Three-wire type 2 |
| F5.00 | DI1 Terminal Function Selected | 1 | Run command |
| F5.01 | DI2 Terminal Function Selected | 2 | Forward and reverse direction |
| F5.02 | DI3 Terminal Function Selected | 3 | Three-wire operation control |
Three-wire control mode 2: For example, the DI3 terminal allocates the three-wire running control function, the DI1 terminal allocates the command function, and the DI2 terminal allocates the forward/reverse running direction function. Connect the start-stop button to DI3 terminal, and enable the operation to connect to DI1 terminal; Connect the forward/reverse operation button to the DI2 terminal.
Among them: SB1 Stop button;SB2 Forward and reverse control buttons; SB3 Run button;
Refer to the following table for running commands corresponding to switching signals:
| SB2 | Run command |
| 0 | Forward running |
| 1 | Reverses running |