TECHNICAL DATA SHEET
02-074 Issue 6
canford.co.uk
CANFORD GROUP LTD, Elliott House, Crowther Road, Washington, Tyne & Wear, NE38 0BW, UK
TECHNICAL SPECIFICATION
Indicating meter required to:
BSEN 6840: pt 10: 1991; IEC268-10
Input signal:
0dBu (+/- 3dBu)
Resolution of meter drive circuitry:
8 bit
Resolution of rectifier:
10 bit @+14dBu
Input impedance:
100kO (per leg) balanced
Frequency response:
20 - 16000Hz
Power supply requirements:
12-30V DC or 6V to 15V DC @ 25mA
Dimensions:
67 x 54mm
Weight:
25g
CANFORD PPM DRIVE CARD
58-321
CANFORD PPM DRIVE CARD MONO
This PPM drive card incorporates a micro controller to
control the PPM characteristics and can be run from either
a single or dual rail power supply and be driven from either
balanced or unbalanced sources. Peak LED illuminates at
PPM 6, if fitted. The frequency response has a roll-off above
16kHz and there is provision for an external meter and
internal PPM SLOW mode.
Observe handling precautions for ESD sensitive devices at
all times.
CONNECTIONS
•
For balanced use connect input signal to pins 6 and
7. Connect screen to pin 8 for single rail or supply
common for dual rail operation.
•
For unbalanced use connect input signal to pin 6 and
screen to pin 7. Also connect screen to supply common
or pin 8 in single rail supply.
•
Only one LED can be fitted directly.
•
An external meter may be connected via pins 1 and 2
(see wiring diagram).
•
Connect pin 3 to pin 4 to activate PPM SLOW mode.
(Refer to connection diagram fig. 1).
For optimal EMC performance, care must be taken with
appropriate shielding of external connections and with
grounding/routing of signal and control cables. Ideally,
the assembled meters should be housed in screened
cases and power supply common should be earthed as
close as possible to the PCB. Ferrite rings may be used
to improve performance in sensitive areas. In particular,
any long cables to remote control switches and external
meter should be via earthed screened cable. Ceramic de-
coupling capacitors may be connected close to the PCB if
necessary.
POWER SUPPLIES
Power can be dual or single supply. Single 12-30VDC at
25mA is recommended as the ground plane is then 0V. This
gives improvements in the EMC performance of the unit.
CALIBRATION
Calibration of the drive is factory set to PPM4 at 0dBu.
When fitting the meter to the card it may be necessary
to adjust pot RV2, to compensate for the meter tolerance.
After applying 1kHz tone at 0dBu, adjust RV2 to align
the pointer with PPM 4. RV1, Input Gain control, should
not need adjustment but the user may wish to alter the
reference level for systems which are not at 0dBu.