5-3
5.4 MVD Direct Connect Wiring
Note: This section applies only to QTA sensors used in MVD Direct Connect installations.
Note: MVD Direct Connect installations based on the QTA sensor cannot include the MVD Direct
Connect I.S. barrier.
In MVD Direct Connect installations, you must connect the sensor to a remote host and to a power
supply.
5.4.1 Power Supply Requirements
The power supply must meet the following requirements:
•
Power must be supplied from a common floating regulated power supply with the correct
voltage.
•
The voltage requirement for a single sensor is 15–26 VDC. The maximum power consumption
of a single sensor is approximately 3 W.
•
The power supply may be used to power any number of sensors, but must not be used to
power other devices.
•
Use shielded wiring.
•
The power supply must not allow power surges or conducted radio frequency interference
(RFI) to propagate through to its output.
•
The power supply must not be grounded.
•
•
In EU countries, the power supply must meet the requirements of the EMC directive.
•
The power supply cable must comply with the size and length requirements listed in Table 2-1.
A minimum DC input of 15 V is required for each sensor. At startup, the power source must
provide a minimum of 0.2 A of short-term current per sensor. The maximum steady state
current is 0.15 A. For assistance in sizing the power supply cable, refer to Table 5-1 and use
the equation below:
Minimum Supply Voltage = 15V + (Cable Resistance x Cable Length x 0.15A)
Grounding the power supply to the sensor can cause
damage to the sensor or the remote host.
To avoid damaging the sensor or the remote host, ensure
that the power supply to the sensor is not grounded.
CAUTION
Instruction and Operation Manual
X-CM-QmBS-eng
Part Number: 541B052AHG
June, 2008
Section 5 Installing Sensor to Transmitter
QmBS Sensor / QTA Transmitters
