The M1DBH Data Bus Hub requires a Cat 5/6 from the M1DBH all the way to the Bus Device in the field — NO short pigtails then to 4 conduct is allowed. The M1DBH uses 6 of the 8 conductors of the Cat5/6 with two conductors being the return path back to the M1DBH one for Data A and one for Data B. The M1DBH keeps the Data A and Data B in a “Daisy Chain” configuration. Included with the M1DBH is an RJ45 Plug with the 120Ω Ohm Resistor built in. After adding devices to the M1DBH the RJ45 Plug with resistor will be installed into the First Un-Used Port on the M1DBH and connects the 120Ω Resistor across Data A and Data B. When using the M1DBH Hub there is NO NEED to install a Black Shorting Cap (aka Black Jumper) onto and Bus Device or physically install the 120Ω Resistor onto the M1XRF319 or the M1XRF2H Receivers.
The M1 RS485 Data Bus and consist of the following Bus Devices:
- 16 Keypads (M1KP, M1KPB, M1KP2/3, M1KAM, P212S Power Supply) Addresses 1 -16 and are a TYPE 1 Bus Device
- 11 Inputs Expanders which includes Hardwired M1XIN’s and Wireless Receiver M1XRFTWM, M1XRF319 and M1XRF2H Addresses 2-12 Depending on the model —- refer to the Installation Manual for each model for specifics on compatible Bus Addresses. Input Expanders are a TYPE 2 Bus Device
- 11 M1XOVR 8 Relay and 8 Low Voltage Output Expanders Addresses 2-12 TYPE 3 Bus Device
- 7 Serial Port Expanders , M1XSP and variations of the M1XSP for example the M1SLZW Addresses 1-7 TYPE 5 Bus Device
- Type 4 Bus Devices are for future use
It is OK to have overlapping Address as long it is a Different Bus TYPE — for example Keypad Address #2, M1XRFTWM Address #2 M1XOVR Address #2 and M1XSP Address #2 are perfectly acceptable because they are Different TYPES. You will have issues if you have two of the SAME Type Bus Device set to the Same Address for example two keypads set to address #2 or two M1XINs set to address #2 will be a problem. More information on the Data Bus configuration , Data Bus Device Addressing and Enrollment can be found on page 12 and 13 of the M1 Installation Manual.
The M1s Data Bus is an RS485 Data Bus and according to RS485 Protocol needs to have a 120Ω Ohm Resistor across Data A and Data B at each end of the bus. The two 120Ω Ohm Resistors are in parallel with each other and overall resistance across Data A and Data B should be ~60 -70Ω Ohms.
I suspect you may have issue with the RJ45 connector or the crimp to the connector or the wiring going to the M1XRF319 Receiver. You may want to double check the wiring of the RJ45, or install a new RJ45 connector and double check to make sure going to the M1XRF319 +12V is the Solid Brown, Data A is Solid Green and Solid Orange, Data B is White Green and White Orange and NEG is White Brown.
In your Bus Configuration you have:
- 4 Conductor going to the M1DBH —- correct?
- You have the M1XRFTWM connected to J1 or J2 —- correct?
- In this case you DO NOT place a Jumper on JP3 on the M1 Main Board. You will place a Black Jumper on to JP1 “Term Res” of the M1XRFTWM
To Test Bus Resistance”
- Power Down the M1 System including any secondary power supplies or the P212S power the bus devices
- Un-plug each device from the M1DBH
- Plug the RJ45 with built in 120Ω Ohm Resistor into J1 on the M1DBH
- Measure the resistance Across Data A and Data B at the M1
- You should measure ~60-70Ω Ohms of resistance
- Move the RJ45 Plug to J2 and plug any device into J1
- Measure the resistance across Data A and Data B — You should measure ~60-70Ω Ohms of resistance
- Keep repeating this process of moving the RJ45 Plug to the next un-used Port and plugging in another bus device and measuring the resistance until all of you bus devices are connected
- The Resistance should always be ~60-70Ω Ohms However this does not mean the bus wiring is correct you should still have Data A and Data B reversed at some point BUT still get a good resistance reading
- If the resistance readings are good power up and measure the DC Voltage at each Bus Device — You should measure 12-14 VDC
Your Question “Any ideas how to fix the ElkM1XRF319 “ See Above” And the question “is my data bus address 2 fine” — What device are your referring to as Address #2? You can have a keypad at Address #2 and the M1XRFTWM MUST be address #2 .