FMBM Operation

The Davicom FMBM can be operated in three different modes.

The first mode uses the front-panel LCD and 3 control buttons. This is for stand-alone operation where the FMBM’s alarm contacts are connected to external alarm monitoring status inputs.

The second mode operates through any Davicom Intelligent Remote Control system that is running firmware version 5.42 or higher. This mode offers remote control capability and close integration with the Davicom’s automation structure.

The third mode is via the FMBM’s back-panel USB connector in conjunction with a communications-terminal program such as HyperTerminal, commonly found on Windows Operating Systems. The FMBM’s USB communications driver must be installed prior to operating in this mode. This driver is included on the CD supplied with the FMBM.

Local operation with front-panel display & buttons

Default display

If an appropriate high-level signal or antenna is connected to the unit and it is powered from a 12 Vdc power supply, the FMBM will automatically start displaying the receive frequency and modulation level, alternating between the frequency drift and signal strength. Display of stereo presence/absence (ST/MONO) is permanently present on the bottom right of the LCD screen.

Note that at all times when in this Default display mode, the UP and DOWN buttons control the audio output level going to the headphones.

The 2 screens below show displays that would typically appear when tuned to a monophonic station at 104.7 MHz. The display alternates between the 2 screens over an 8 second period. The shaded fields would obviously vary depending on the frequency selected and on the station’s signal parameters.

The fields indicate the selected receive Frequency, the frequency Deviation (FM Modulation), the presence (or absence) of a Stereo (Mono) signal, the amount of carrier Frequency Drift between the received carrier frequency and the FMBM’s highly-stable internal frequency reference and finally, the Receive Signal Strength Indicator (RSSI). If the High-Level RF input is selected, RSSI is replaced by Lvl, and the units become Volts instead of dBm. If the AM band is selected, typical displays would be as shown below, where Mod is the AM Modulation index.

When the signal source is set to MPX, these the following screen is displayed:

Menu selection mode

Pressing the MENU button once will display the first menu item. Pressing the UP (or DOWN) button after the first MENU press scrolls to the next (or preceding) menu item. Pressing a second time selects that menu item and allows it to be modified by pressing the UP or DOWN buttons. The table below presents the menu items in order and their possible settings.

Menu items and description

*Note that on the AM band, the term Deviation is replaced by Modulation.

1- Exit exits the Menu selection mode and returns to the default display. Note that an Exit exists at both the very beginning and very end of the Menu Selection mode. Firmware version is also shown in the Exit screen.

2- Band AM-FM allows selection between the AM and FM broadcast bands. Note that an appropriate antenna or high-level signal must be connected to the rear-panel connectors.

3- Tuning Step allows selection between steps of 50, 100 or 200 kHz when tuning across the FM broadcast band. In AM Mode, the steps are 1 and 10 kHz. Note that certain settings can produce difficult reception conditions. For example, if starting at 104.2 MHz and selecting 200 kHz steps, one could never actually select actual operating frequencies as used in North America (104.1, 104.3, 104.5 …).

4- Frequency is for the actual operating frequency of the receiver. Operating frequency covers 88 to 108 MHz in FM mode and 520 to 1710 kHz in AM mode. Note that the receive frequency doesn’t actually become active until the MENU button has been pressed to exit the selection mode.

5- Alarm Display shows a summary of the alarms that are active in the unit.

6- RF Input selects internal calibration and settings to account for the 51dB attenuator that is in series with the high-level input. Both the high-level and low-level (antenna) inputs are connected together through the 51dB attenuator. Therefore, only one input must be connected at a time for readings to be accurately measured.

7- MPX Mode selects the MPX connector as an Input or an Output.

8- Source selects the signal source: Tuner (Antenna) or MPX (MPX connector).

9- Audio Level sets the audio level for the rear-panel audio outputs and is adjustable from 0 to +10 dBm referenced to 600 Ω (0 to +10 dBu). This menu also sets the audio level of the digital AES output on the rear panel. When the audio level is set to +8 dBm, the audio level on the digital AES output is -14 dBFS.

10- Peak Deviation Limit sets the threshold above which the deviation peak counter will increment. It is adjustable from 1 to 150 kHz.

11- Peaks/min Count sets the number of counts in the preceding minute above which the High Deviation Alarm will become active. The count threshold can be set from 1 to 9 counts per minute. When the “OFF” mode is selected, the alarm will be active each time the deviation exceeds the limit set in step 10, and it will toggle normal when the deviation falls back below the limit.

12- Low Deviation Limit sets the level below which the Low Deviation Timeout timer starts. It is adjustable from 0 to 79 kHz.

13- Low Deviation Timeout sets the number of seconds during which the deviation must be continuously below the Low Deviation Limit for a Low Deviation Alarm to become active.

14- Power Monitor Calibration operates in 2 different modes, depending on which RF Input is selected (Antenna or High Level in Menu step 6). If Antenna input mode was selected, pressing the MENU button here in Menu step 14, sets a new reference level that is used by the FMBM as the normal receive signal level. See Menu step 15 for setting the alarm level that will be x dB below this normal level. If High-level input mode was selected in Menu item 6, the display shows the voltage that is output to the rear panel RF Power Monitor output. This output level is calibrated through the front-panel potentiometer (RF Power Monitor Adjust.) while injecting a known level of RF at the High-level input connector.

15- Low Power Limit sets the number of dB below the Power Monitor Calibration level (Menu item 14) that will set a low-power alarm. It can be set from -1 to -9 dB for Highlevel mode and from -1 to -99 dB for Antenna input mode.

16- Frequency Drift Limit sets the frequency range beyond which the FMBM will activate the frequency drift alarm. It can be set to any value between 0.5 kHz to 10 kHz and is only used on the FM band.

17- Stereo Alarm setting allows users to enable or disable the stereo presence alarm. This is useful for stations that normally transmit in Mono mode only. It is used on the FM band only.

18- RDS Data turns on the RDS data display mode that shows the {Program Station}, {Program Type} and {Radio Text} data as it is transmitted by the station. It is useable on the FM band only for stations that do transmit RDS or RDBS data. RDS data is displayed for a period of approximately 2 minutes and then the display reverts to its default mode.

19- RF Alignment allows fine tuning of the RF input circuit to optimize signal reception depending on antenna type and matching. Selecting this Menu item displays a tuning setting between 0 and 127 as well as an RSSI level in dBm. Press the up or down buttons to change the tuning setting in order to maximize the receive signal level. Once the highest signal is achieved, exit the Alignment mode by pressing the Menu button again.

20- Firmware Upgrade allows users to upgrade the FMBM’s operating firmware to install new versions that could incorporate improvements, new features and corrections to bugs. Selecting this menu item, without pressing the upgrade button, also shows the current version number of the firmware installed in the unit. See this article for details.

21- Exit exits the Menu selection mode and returns to the default display. Note that an Exit exists at both the very beginning and very end of the Menu Selection mode. Firmware version is also shown in the Exit screen.

Remote operation through Davicom unit

Using the supplied cable, connect your FMBM’s USB port to the back-panel USB Port on any Davicom unit (DV-200, Mini and Micro). Note that the Davicom units MUST be running Firmware Version 5.42 or higher. If this is not the version of Firmware you have, please go to the Software & Firmware page to find the newest Firmware.

Power-up the FMBM and wait a few seconds for it to automatically sync with the Davicom. To connect to the FMBM through the Davicom, first connect to the unit in your usual way, startup DavLink and connect to your unit.

Once connected, click on the Configuration icon in the DavLink Toolbar:

The following Configuration window will appear. Select the Devices Tab.

Then click on the “Davicom Expansions” button as shown below.

Clicking on the “Davicom Expansions” button brings-up the window below which allows configuration of the FMBM and all its settings:

If the FMBM was not connected or had not been detected by the Davicom, a message at the top of the window would have indicated that no FMBM was detected.

FMBM drop-down list: The Davicom can accommodate up to 4 FMBM units which are selected through the FMBM drop-down list.

Auto Read: Checking the Auto Read box ensures that the readings displayed in the AM/FM Broadcast Monitor screen are automatically refreshed every time a different unit is selected from the FMBM drop-down list. Otherwise, the Read button must be pressed to refresh the display with the latest readings from the corresponding FMBM.

Read & Write: Clicking on these buttons reads the data from the FMBM, or writes data to the FMBM following any changes made in the configuration screen. The Write operation is necessary because changes made to the settings displayed on the screen are only present in your PC and aren’t transferred to the connected FMBM until the Write button is pressed.

Descriptions (Default and Alternate): These descriptions are used to identify the FMBM whenever alarms are sent or events are logged in the Davicom unit’s System Log. The Default description is in Unicode and can accommodate any compatible international alphabet. The Alternate description is in ASCII and is generally used for an English description. The Davicom automatically copies the Default into the Alternate description if the Alternate field is empty and if the language is ASCII compatible.

Band: The operating frequency band is selected with the Band drop-down list

The operating frequency is set in the Frequency field. For AM, it can be set from 520 to 1710 kHz and for FM it can be set from 88 to 108 MHz. Note that the actual frequency isn’t transferred to the FMBM until the Write button is pressed.

Received Signal Strength Indicator (RSSI): The Low Limit field indicates the number of dB below the Normal Level at which the RSSI Alarm will be set. The Normal Level is set on-site with the FMBM’s front-panel screen and Menu buttons. Whenever the RSSI alarm turns on, the Davicom’s 1FM01 flag will become true. This flag can then be used in the Davicom’s logic structure with Virtual Logic Gates to perform different actions and send alarms.

Note that if more than one FMBM is connected, the Davicom will create flags 2FM01 for the 2nd FMBM, 3FM01 for the 3rd FMBM and so on.

Deviation: The Deviation (Modulation) Low limit field indicates the number of kHz of deviation below which the Low Deviation alarm will be set to on. Note that this low-deviation condition must be present for a time greater than the time set in the Low Deviation Timeout field explained below. This alarm will also turn on the Davicom’s 1FM03 flag which can be used with Virtual Logic Gates to perform different actions or make alarm calls.

The Deviation (Modulation) High limit field indicates the number of kHz of deviation above which the High Deviation counter will make one count (see “High Deviation Alarm counts per Minute” below).

High Deviation Alarm counts per minute: This field indicates the number of high-deviation counts per minute, above which the High Deviation Alarm and 1FM03 flag will be turned on.

Low deviation: Timeout This field indicates the time, in seconds, during which the low deviation condition must be continuously present for the Low Deviation Alarm and 1FM03 flag to be turned on.

Frequency Drift Limit: The frequency Drift Limit field indicates the number of kHz above which the Frequency Drift Alarm will be set to on. This alarm will also turn on the Davicom’s 1FM02 flag which can be used with Virtual Logic Gates to perform different actions or make alarm calls.

The following table summarizes the Davicom’s FMBM-related logic flags.

NOTE: FMBM5/6/7/8 Active Only when FMBM1 is in Scan Mode

To view the current levels and alarm states of the FMBM, go back to the DavLink main screen and click to the “View” (eyeglasses) icon as shown below.

This will display the screen as shown below.

Click on the Devices tab and then on the FMBM button.

This will display the screen shown below.

Remote operation with a PC

The FMBM can also be operated through its back-panel USB interface. This requires using a PC with a USB Port and a communications program such as HyperTerminal that is supplied with the Windows XP OS. Other equivalent terminal-type programs like TeraTerm freeware can also be used. This mode of operation is known as the VT-100 mode.

You must also have previously installed the FMBM’s USB driver so that your PC can communicate with the FMBM. This driver is included in the software package found on the CD supplied with the FMBM (see this article).

The communications parameters that must be set in your communications program (HyperTerminal or equivalent) are: 115200 baud, No parity, 8 bits, 1 stop bit, no flow control and the appropriate COM port. Once communications is established, enter “M” for Main menu and the following screen will appear.

Menu items are selected simply by pressing the corresponding letter on your keyboard.

Pressing A (for Radio Settings) will display the following screen and allow setting of parameters such as the operating band, receive frequency, etc.

Starting from the Main VT-100 menu screen and pressing “B” will display the menu shown in the image below.

The following screens are obtained by pressing the corresponding letters on your keyboard.

Note that the “F” key has no effect in VT-100 mode

Note that the “I” Update Firmware selection is used to set the FMBM in firmware update mode where it awaits input from the “FMBMUpgradeTool.exe” software (see this article).

Pressing the “X” key exits the VT-100 mode and terminates communications. To re-start, simply press the “M” key again.