Configuring the Davicom Unit to Work With a MEXM

If you are not familiar with the Davicom unit and the DavLink software, please refer to the DV-200 Knowledge Base topic or the DV-200 Reference Manual (PDF).

MEXM autodetection by the Davicom

Autodetection is possible for both RTU and TCP connection mode. Note that these two modes are exclusive: mixed communication modes (simultaneous operation in both RTU and TCP mode) are not possible.

To add a MEXM to a Davicom unit configuration:

RTU MODE:

  • If more than one MEXM is used: plug all units together in daisy-chain
  • Set the communications-mode selector switch to any position between 1 and 7
  • If more than one MEXM is used, make sure the communications-mode selector switches are set to different positions for each unit
  • Power up the units
  • Connect the USB cable from the first MEXM-1 to the Davicom unit
  • In DavLink, go to Unit Configuration / Devices / ModBus and click on AutoDetect

TCP MODE:

  • Set the communications-mode selector switch to position 0
  • Connect the ETHERNET cable to the MEXM and to the Davicom
  • Power up the MEXM
  • In DavLink, go to Unit Configuration / Devices / ModBus and click on AutoDetect

Manually adding a MEXM as a Modbus slave in TCP

Go to Unit Configuration / Devices / ModBus Setup window and check that the settings are as shown below:

Manually adding a MEXM as a Modbus slave in TCP mode

Warning: the MEXM module checkbox must be checked for the MEXM to work properly.

To add another MEXM in TCP mode, select a blank entry in the Slave Setup table (image above) and fill out the fields with the same parameters except the IP address which must be different for each additional unit and within the same subnet.

Manually adding a MEXM as a Modbus slave in RTU

Go to Unit Configuration / Devices / Modbus Setup window and fill in the information as shown in the image below.

Manually adding a MEXM-1 as a Modbus slave in RTU mode

Warning: the MEXM module checkbox must be checked for the MEXM to work properly.

To add more MEXM units in RTU mode, you have to select a blank entry line in the Slave Setup table (image above) and fill in the blank fields with the same parameters except the RTU Address which must be the same as the one selected on the TCP / RTU communications-mode rotary switch of the MEXM.

Comm Loss settings

The Davicom can be configured to automatically signal an alarm, and/or enter Pause mode, when there is a communications problem between the MEXM and the Davicom. By default, the settings are set for: MAJ1 alarm call, Pause mode, High Sensitivity. These settings can be configured under the “Slave Problem” tab (see image below) when the MEXM is set to the TCP or RTU communications mode.

The High, Medium, Low Sensitivity settings increase the tolerance of the Davicom to communications errors before declaring a COMM LOSS

Comm loss default parameters (TCP or RTU)

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