====== Wireless Modbus-to-Modbus bridge ======

**Wireless Modbus-to-Modbus bridge**

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| Model number: ^ WM-1       |
| Frequency:    | ISM 868MHz (EU) |
| Dimensions:   | 93x45x27 mm     |

===== Applications =====

  * Replacement for RS485 wiring solution with wireless. Optimal for long range Modbus RTU serial communications with half duplex configuration.

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===== Installation and mounting =====
  * :!: Carefully open WM-1 module and configure serial communication with jumpers. (Default configuration is 9600bps, 8N1 with normal timeout)
  * :!: Place WM-1 module at least 10cm from other objects. Installation is not recommended inside metal cabinets.
  * Connect RS485 terminals to WM-1 RS485 terminals
    * A - A
    * B - B
    * C - GND
  * Connect to 230V power supply
  * Bind modules to wireless network



{{ wiki:20_rdc_charger:03_hardware:wm1_module_diagram.png?nolink&0x500  }}
{{ wiki:20_rdc_charger:03_hardware:wm1_mounting.png?nolink&0x500  }}

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===== Features =====

  * replacement for RS485 wiring
  * Modbus RTU serial protocol
  * wired/wireless combinations
  * very long range, no hopping
  * protected private connection
  * multiple slaves per device
  * multiple addressable groups


===== Technical specification =====

| Power supply:          |                                230V, 50/60Hz, 1W |
| Ingress protection:    |                                    IP20 |
| Operating temperature: |                                 -20..50°C |
| Storage temperature:   |                               -40..85°C |
| Relative humidity:     |                              0..85% n/c |

===== Terminals and wiring ===== 

| To power sensor ^ A | RS485 bus  |
| :::            ^ B | :::        |
| :::            ^ C | :::        |
| To power supply ^ L| 230V AC |
| :::             ^ N| :::     |

{{ wiki:20_rdc_charger:03_hardware:wm1_wiring.png?nolink&0x200  }}

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===== Serial configuration and timeout =====
  * Available baudrates 2400, 9600, 19200, 38400 bps
  * Data bits and parity 8N1, 7E1, 8E1, 8N2
  * :!: Max 64 bytes per transmition
  * Integrated 240 Ohm termination resistor

{{ wiki:20_rdc_charger:03_hardware:wm1_serial.png?nolink&0x500  }}

===== Wireless binding =====

==== Create new secure group ====
  
  * turn on all devices at the same time
  * within 10 seconds, while RF LED is blinking, press and hold button on one of the devices
  * after a second, the new address is randomly generated and sent to all devices. RF LED will blink 3 times to confirm the new address.

{{ wiki:20_rdc_charger:03_hardware:wm1_configuration_1.png?nolink&0x500  }}

==== Add new device to the group ====
  
  * turn on the device
  * within 10 seconds, press and hold button on one of the existing devices
  * after a second, the existing group address is sent to the new device. RF LED will blink 3 times to confirm the address is sent.

{{ wiki:20_rdc_charger:03_hardware:wm1_configuration_2.png?nolink&0x500  }}

==== Topology examples ====
  
  * Modbus master, connected to 12 slaves using a pair of WM-1 devices
  * Modbus master, connected to 10 slaves, organized in two groups
  * Modbus master, connected to 5 slaves, each one having local WM-1 device

{{ wiki:20_rdc_charger:03_hardware:wm1_topology.png?nolink&0x500  }}

==== Multiple groups ====
  
  * When the system has two or more separate Modbus lines, they should be configured as separate groups. 
  * Each group has a single master and one or more slaves.
  * Groups can't talk to each other, but they share the same bandwidth. 
  * Two masters may start transmitting at the same time causing collisions. 
  * To reduce number of missed messages, keep the traffic low.
  

{{ wiki:20_rdc_charger:03_hardware:wm1_multiplegroups.png?nolink&0x500  }}

===== Connection check =====
  * Press button shortly
  * RF LED will blink shortly on each connected device
  * Serial interface is unaffected


{{ wiki:20_rdc_charger:03_hardware:wm1_connectioncheck.png?nolink&0x150  }}

===== Factory reset =====
  * Hold button and turn the device ON
  * RF led will blink twice. Group address is now reset to default. 
  * Other devices will not be affected.

{{ wiki:20_rdc_charger:03_hardware:wm1_factoryreset.png?nolink&0x200  }}