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Wiring diagram of the serial RS232/RS485
Certain ACE have RS232 ports or configurable RS232/485 ports.
- RS232 ports are commonly used for interfacing HMI and other devices through Modbus RTU communications. They are also commonly used to interface cellular transceivers for internet of things applications and can be used in ASCII communications mode to communicate to any device that has an RS232 port.
- RS485 ports are commonly used in multi-unit systems and for longer distance communictions.
- Our serial port is a true standard RS232/485. It is NOT a TTL level (0 / 5 VDC) : A logic high is represented by a negative voltage -5 while a logic low transmits a positive voltage +5 V.
ACE RS232 ports have three pin connectors. The illustration on the right shows the connections.
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Some ACE have serial ports that can be configured as either RS232 or RS485. When configured as RS232, the connections are identical to the connections shown for the dedicated RS232 ports. | |
If the port is configured for RS485, the two connections used are
The ground can be connected to the cable shield. However, the shield should only be connected at one end of the cable. |
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Wirring of the HMI serial port
HMI D-sub 9 pins View from outside 1 2 3 4 5 ![]() |
RS232, RS485 and RS422 pins |
Wirring from the HMI to the RS232 3 position plug of the ACE
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RS-485 network wiring
Wire the 2-wire device’s send pin (TXD) to both TXD- and RXD-. Wire the device’s receive pin (RXD) to both TXD+ and RXD+.
Note: On some other devices, RS-485 is configured for four-wire communication by default. To connect a two-wire device, you will need to short-circuit the transmit and receive signals on the RS-485 port.
Generally, the jumpers are on these pins (Follow your device instructions):
- Pin 8 and Pin 4 (TXD+ and RXD+)
- Pin 9 and Pin 5 (TXD- and RXD-)
Wirring issue
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If you don’t see this indicator light blinking on your HMI, it’s probably a wiring cable problem. |