Series Interface Method
RS-232C channel is communicated with other device with a 9-pin connector.
It is directly communicated with a long-distance device, using a modem, as well as with other device.
Pin | Function | Name | Direction of Signal | Description |
1 | Carrier Detect | CD | Inside to outside | Signal wire that DCE informs DTE about the detection of carrier |
2 | Received Data | RXD | Outside to inside | Signal wire receiving data |
3 | Transmitted Data | TXD | Inside to outside | Signal wire sending data |
4 | Data Terminal Ready | DTR | Inside to outside | Signal wire that DTE informs DCE about the state that DTE is able to send and receive |
5 | Signal Ground | SG | Both directions | Ground wire for signal |
6 | Data Set Ready | DSR | Outside to inside | Signal wire that DCE informs DTE about the state that DCE is able to send and to receive |
7 | Request To Send | RTS | Inside to outside | DTE is ready and requests DCE to send data. |
8 | Clear To Send | CTS | Outside to inside | Signal wire that DCE inform DTE about the state that DCE is able to send |
9 | Ring | RI | Outside to inside | Signal wire that DCE inform DTE of receiving RING |
Connection with a modem
A long-distance communication is available.
modem interface is described.
PLC(RS-232C) | Signal Direction | Modem | ||
Pin | Name | Name | Pin | |
1 | CD |
| CD | 8 |
2 | RXD | RXD | 3 | |
3 | TXD | TXD | 2 | |
4 | DTR | DTR | 20 | |
5 | SG | SG | 7 | |
6 | DSR | DSR | 6 | |
7 | RTS | RTS | 4 | |
8 | CTS | CTS | 5 | |
9 | RI | RI | 22 |
Connection with a null modem
PLC and Computer/Communication device: There are 3-wire type and 7-wire type.
In case that a PC is connected with a RS-232C connector, RXD, TXD and SG is to be connected in 3-wire type.
RS-422 Interface
A 6-pin connector is used for RS-422 interface. The functions and names of the pin and the flow of data are described as follows.
Pin | Name | Direction of Signal PLC Device | Function |
1 | SDA |
| Sends data. (+) |
2 | SDB | Sends data. (-) | |
3 | RDA | Receives data. (+) | |
4 | RDB | Receives data. (-) | |
5 | S.G | Ground wire of signal | |
6 | F.G | Ground wire of frame |
RS-422 channel can be connected with other device for RS-422 and RS-485 (Multi-drop).
Computer Link | Direction of Signal PLC Device | Outside Communication Device | |
Pin | Name | ||
1 | SDA |
| RDA |
2 | SDB | RDB | |
3 | RDA | SDA | |
4 | RDB | SDB | |
5 | S.G | S.G | |
6 | F.G | F.G |
The following is an example to connect RS-485 channel with an outside device. At this time, as a sending wire shares with a receiving one (Half Duplex), the channel mode is to be set up as RS-485.
Computer Link | Direction of Signal PLC Device | Outside Device | |
Pin | Name | ||
1 | SDA |
| SDA |
2 | SDB | SDB | |
3 | RDA | RDA | |
4 | RDB | RDB | |
5 | S.G | S.G | |
6 | F.G | F.G |