Table of Contents
Advertisement
Quick Links
Advertisement
Table of Contents
Summary of Contents for BEL BM-A1
- Page 1 BM-A1 Audio monitor/alarm system User’s Guide Version 0.2 05/02/04...
- Page 2 BEL DIGITAL AUDIO BM-A1 BEL (Digital Audio) Ltd. has made every effort to ensure the accuracy of information contained within this document which is nevertheless supplied for information purposes only and does not constitute any form of warranty or guarantee.
-
Page 3: Table Of Contents
Adjusting analog input level Adjusting audio monitor output level Adjusting bargraph break-points and ballistics Inserting bargraph graticules BM-A1 SERIAL PROTOCOL VERVIEW Frame format OMMANDS ATA FORMATS ROBLEM SOLVING Sample problems and their solutions PECIFICATION 2004 BEL (Digital Audio) Ltd... -
Page 4: Main Features
Audio input signals can be in the form of analog or AES. The BM-A1 accepts audio inputs in groups of 4 channels from the selected source and can direct any two from these to the speakers. The same signal is also available as a line-level audio monitor output. -
Page 5: Bm-A1
The headphone output, which is taken before the limiters, mutes the speakers when used. Alarm tone is added just before the speaker output. When select switches are used a soft mute is applied to the audio to reduce glitches. 2004 BEL (Digital Audio) Ltd Version 0.2... -
Page 6: Operation
Selecting sources The audio source switch routes either analogue or AES source audio to the speaker selectors, the bargaphs and the monitoring line output. Using alarms The BM-A1 can provide the following warnings: Alarm event Notes Alarm indication Audio loss... -
Page 7: Alarm Arming
To prevent the anti-phase detector from generating intermittent alarms, only persistent anti- phase conditions are used to raise an external alarm or generate an audio tone. An alarm is generated when an anti-phase condition exists for more than 10 seconds. 2004 BEL (Digital Audio) Ltd Version 0.2... -
Page 8: Bargraph Scales
BM-A1 scale graticules Note: Bargraph color transition points and peak hold decay may also be adjusted internally. Refer to the Configuration chapter for switch settings and graticule fitting instructions. 2004 BEL (Digital Audio) Ltd Version 0.2... -
Page 9: Installation
BM-A1 Installation The BM-A1 1U frame may be installed in 19 inch bays with 327mm depth including typical cable and connector depth. The dimensions of the BM-A1 are 483x283x44.3. Its weight is 5kg and the max power dissipated is 60 W. -
Page 10: Rs232 Host Interface Connector Pinout
Format: 8 bit, no parity, 2 stop bits Description Not connected Rx (from host) Tx (to host) Not connected Not connected Not connected Not connected Not connected Note: A null-modem lead will be required to interface to a PC. 2004 BEL (Digital Audio) Ltd Version 0.2... -
Page 11: Configuration
Bargraph settings – SW2 and SW6 main board, near power supply Warning: Configuration instructions are for trained personnel. To avoid dangerous electric shock, do not remove any covers or carry out adjustments unless qualified to do so. 2004 BEL (Digital Audio) Ltd Version 0.2... -
Page 12: Adjusting Analog Input Level
Note: It is intended that only one switch lever is set ON for each analog input. The ON position is obtained with a switch lever in the direction of the arrow (downward in the above drawing). *Clockwise rotation increases gain. 2004 BEL (Digital Audio) Ltd Version 0.2... -
Page 13: Adjusting Audio Monitor Output Level
Note: It is intended that only one switch lever is set to ON for each monitor output. The ON position is obtained with a switch lever in the direction of the arrow (downward in the above drawing). *Clockwise rotation increases gain. 2004 BEL (Digital Audio) Ltd Version 0.2... -
Page 14: Adjusting Bargraph Break-Points And Ballistics
Scale type Extended VU NORDIC No scale No scale Note: The OFF position is obtained with a switch lever in the direction of the arrow, (to the right in the above drawing). 2004 BEL (Digital Audio) Ltd Version 0.2... - Page 15 SW2-1 SW6-8 SW6-7 SW6-6 Segment from bargraph top None Note: It is not possible to set 25 red and 25 amber segments, since there are only 25 segments for level display purposes. 2004 BEL (Digital Audio) Ltd Version 0.2...
- Page 16 Select from none to 25 using SW6-5, SW6-4, SW6-3, SW6-2 and SW6-1 as follows: SW6-5 SW6-4 SW6-3 SW6-2 SW6-1 Segment from last RED ZONE None Note: Any remaining unassigned segments will be green. 2004 BEL (Digital Audio) Ltd Version 0.2...
-
Page 17: Inserting Bargraph Graticules
BEL DIGITAL AUDIO BM-A1 Configuration Inserting bargraph graticules The following bargraph scale graticules are supplied with each BM-A1: BM-A1 scale graticules To apply a graticule proceed as follows: • peel back the protective backing from the chosen graticule • apply the graticule to the space between a pair of bargraphs •... -
Page 18: Bm-A1 Serial Protocol
BM-A1 BM-A1 serial protocol Overview The BM-A1 is automatically placed in the remote mode upon receipt of a valid RS232 command. The front panel can be reactivated by powering off and on or by sending it a disconnect command. Commands to be communicated to the remote unit (BM-A1) are arranged in frames. These frames will then be sent to the remote unit, which will always reply with either ACK for acceptance or NAK for rejection. -
Page 19: Commands
It is calculated thus: checksum = (character+checksum) AND 0x7F FOR ALL CHARACTERS IN FRAME. End Flag: A character 0XFE ends the frame. Commands Commands from the remote controller to the BM-A1. Code(Hex) Function Reply General prompt for a reply C0 - ACK (OK) -
Page 20: Data Formats
BEL DIGITAL AUDIO BM-A1 BM-A1 serial protocol Data formats General Prompt (0x80) This command will cause the BM-A1 to respond with an ACK or NACK reply. It can be used to poll for alarms. Set up switches (0x83) Bit 7 Bit 6... - Page 21 3 Second hold time 7 Second hold time Indefinite hold time AES offset This bit selects the bar graph offset when AES is input to an analog bar graph. Code Function -18dB -20dB 2004 BEL (Digital Audio) Ltd Version 0.2...
- Page 22 Over-level Byte 1 Disable The Auto bit will cause the BM-A1 to generate spontaneous ACK signals every second while an alarm is active. The toggle disable bit will inhibit the set-up function of the front panel toggle switch. Request Detail (0x85) This command will cause the BM-A1 to respond with a frame containing the command 0XC5 and data describing the state of the unit and any alarms.
- Page 23 A character was detected before receipt of a start character. A checksum error occurred. The erroneous value is placed in Byte 1 RS232 format 8 data bits, no parity, 2 stop bits, 9600 Baud. 2004 BEL (Digital Audio) Ltd Version 0.2...
-
Page 24: Problem Solving
AES B – lights yellow to indicate the presence of the AES B input • ALARM – lights yellow to indicate an active alarm event Note: The bottom bargraph segment in each bar is used as an audio alarm. 2004 BEL (Digital Audio) Ltd Version 0.2... -
Page 25: Sample Problems And Their Solutions
Note: In the unlikely event that the unit ‘locks up’ switch the unit off at the rear for a few seconds and then restore power. 2004 BEL (Digital Audio) Ltd Version 0.2... -
Page 26: Specification
-80dB w.r.t. maximum output Speaker driver units Peak acoustic level (@2ft) 100dB SPL Shielding Magnetic Meters Level meters 4 x hi-resolution tri-color bargraphs (All audio measurements made using Audio Precision un-wtd 22Hz to 22kHz 2004 BEL (Digital Audio) Ltd Version 0.2... - Page 27 Power 60W (max) 90-264 VAC 50-60Hz Autoselect, Fuse 4A HAC Environmental Temperature 0°C to 30°C Humidity 70% max (non-condensing) Weight 11.6lbs (5kg) Computer interface 9 pin RS-232 male PC-AT serial interface (null-modem) 2004 BEL (Digital Audio) Ltd Version 0.2...