Brandywine PDU-240 User manual

MANUAL P/N 900000154 REV A
User Guide
Pulse Distribution Unit
Model PDU-240
P/N 018000501
Revision B
June 2017
Brandywine Communications
1153 Warner Avenue
Tustin, CA 92780
[phone]
[phone]
http://www.brandywinecomm.com/

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Revision History
REVISION
DATE
COMMENTS
A
5-20-2016
Original release of PDU-240 user guide.
B
9-21-2017
Added information on fuse replacement

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Safety Warnings
WARNING: This unit contains lethal AC voltages.
Disconnect the unit from the AC supply before removing
the cover.
WARNING:
The lightning flash with an arrowhead inside of an equilateral triangle is
intended to alert the user to the presence of un-insulated “dangerous
voltage” within the product’s enclosure. The “dangerous voltage” may be
of sufficient magnitude to constitute as a risk of electrical shock to people.
CAUTION:
The exclamation point inside of an equilateral triangle is intended to alert
the user to the presence of important operation and maintenance
instructions in the user guide.

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Table of Contents
1 Specifications..................................................................................................5
1.1 Inputs........................................................................................................5
1.1.1 Reference Pulse Input......................................................................5
1.1.2 Fault Discrete (Optional)..................................................................5
1.1.3 Fault/Status.......................................................................................5
1.2 Outputs.....................................................................................................6
1.2.1 Reference Pulse Output...................................................................6
1.3 Switches and Indicators............................................................................7
1.3.1 Status LED Indicators......................................................................7
1.3.2 Environmental ..................................................................................7
1.3.3 Power ................................................................................................7
1.3.4 Physical.............................................................................................7
2 Option Configuration Sheet.............................................................................8
3 Unpacking and Installation ..............................................................................9
3.1 Unpacking.................................................................................................9
3.2 Installation.................................................................................................9
3.3 Connections............................................................................................10
3.3.1 Alarm Input Connection.................................................................10
4 Operation.......................................................................................................11
4.1 Powering the PDU-240...........................................................................11
4.2 Selecting the Input Reference.................................................................11
4.3 Fault Indicator.........................................................................................11
5 Maintenance and Troubleshooting ................................................................12
6 Calibration.....................................................................................................13
7 Drawings .......................................................................................................14

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1 Specifications
1.1 Inputs
1.1.1 Reference Pulse Input
Pulse: 1 PPS through 10Mhz
Input Levels
o1 level : 2.5V min, 10.5V max
o0 level : 0.25V max
Input Impedance: 50 ohm or 10k ohm. Settable by link, see figure 1
Number of Inputs: 2 with auto selection and manual override from the
front panel toggle switch
Connector Type: BNC
1.1.2 Fault Discrete (Optional)
Number of Inputs: 2
Level: TTL
Active low
Forces a changeover when active for online reference
1.1.3 Fault/Status
Connector Type: DB-9 Female
Mating Connector: AMP P/N 747904-2
Figure 1

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1.2 Outputs
1.2.1 Reference Pulse Output
Number of Outputs: 24
Connector Type: BNC
Output Protection: short circuit proof
Output Level: o1 level: 5V±5% into 50 ohms (10V ±5%
settable with link)
oOptional 1 level: 2.5V into 50 ohm
o0 level: 0.25V max into 50 ohm
Rise Times (10% to 90%)
o0-10V 20ns
o0-5V 15ns
o0-2.5V 10ns
Cross talk: -80 dBc
Spurious: -60dBc
Figure 2

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1.3 Switches and Indicators
1.3.1 Status LED Indicators
Power (Green)
Reference Input A Available (Green)
Reference Input A Online (Green)
Reference Input B Available (Green)
Reference Input B Online (Green)
lAutomatic Reference Selection Selected (Green)
Fault (Red)
1.3.2 Environmental
Temperature:
oOperating: -30 to +60C
oStorage: -40 to +85C
Humidity: 10 - 95% non-condensing
1.3.3 Power
115/230 VAC 50/60 Hz
< 25 W
Fuse Value: T1, 250V, 1A
1.3.4 Physical
1.72” H x 14.5” D x 17.00” W and 1U 19” rack mount
Weight: 7.5 lbs nominal
1.3.5 Input detection time
Setting input available LED time.
oThe detection time in seconds can be adjusted for low frequency
pulses. Set with DIP switch on LED board. Figure 3
1PPS: default at 1 second
10PPS: set to 10 second
1PPM: set to 60 second
Figure 3

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2 Option Configuration Sheet
Configuration Options
2.1 Base Unit
Part Number
2 switched input 24 output 10V level
018000501
2 switched input 24 output 5V levels
018000502
2 switched input 24 output 3.3V levels
018000503
2 independent input 12 output
Group 1 10V
Group 2 10V
018000504
2 independent input 12 output
Group 1 10V
Group 2 5V
018000505
2 independent input 12 output
Group 1 10V
Group 2 3V
018000506
2 independent input 12 output
Group 1 5V
Group 2 5V
018000507
2 independent input 12 output
Group 1 5V
Group 2 3V
018000508
2 independent input 12 output
Group 1 3V
Group 2 3V
018000509
Power Supply Options
85 - 265 VAC 50/60 Hz
018001000
36 - 72VDC Isolated
018001001
18 - 36VDC Isolated
018001002
9 - 18 VDC Isolated
018001003

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3 Unpacking and Installation
3.1 Unpacking
Carefully remove the PDU-240 from its shipping carton. The following items
should be included in the shipment:
1 PDU-240
1 power cord
1 user guide
Note the power entry module on the rear of the PDU-240 chassis. Please take
note of the voltage displayed on the rear of the power entry module and verify
that the voltage matches the local line’s voltage.
WARNING:
REMOVE THE POWER CORD FROM THE PDU-240 BEFORE
ADJUSTING THE LINE VOLTAGE.
CAUTION:
THE PDU-240 WILL BE DAMAGED IF THE INCORRECT AC
LINE SETTING IS USED.
If the AC line setting is incorrect, detach the power cord from the power entry
module. Use a small screwdriver to lift up the fuse cover on the power entry
module to remove the fuse holder. Reverse the fuse holder and re-insert the
fuse holder, making sure that the correct AC line voltage is now displayed on the
rear panel.
3.2 Installation
The PDU-240 should be bolted directly into a 19” rack mount enclosure or
mounted on a shelf. The PDU-240 when fully populated has up to 27 cables
attached to the rear panel, therefore it is recommended that some appropriate
cable strain-relief system be used to support these cables, particularly when the
unit is not supported by a shelf.

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3.3 Connections
Insert the power cord provided in the shipment into the rear power entry module.
Connect the input reference signals to the appropriate connectors on the rear
panel.
NOTE:
FOR CORRECT OPERATION, REFERENCE PULSE A
AND REFERENCE PULSE B MUST BE THE SAME
PULSE RATE, WHICH IS TYPICALLY 1 PPS.
Connect the output cables to the desired output connectors. Any unused
connectors may be left un-terminated.
3.3.1 Alarm Input Connection
The PDU-240 may be used with an external reference such as the Brandywine
Communications GPS8 or PTS system that incorporates a discrete alarm signal.
This alarm signal is used to indicate a fault (e.g. rubidium out of lock) on the
reference signal, although the 1 PPS input signals may be present.
The factory standard PDU-240 configuration is a logic HI signal on the ALARM IN
pin indicating that the input is GOOD. A built in pull-up resistor ensures that if no
ALARM IN connection is made the reference is considered good.

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4 Operation
Refer to Figure 1 for a guide of the front panel controls and indicators.
4.1 Powering the PDU-240
Once all connections to the PDU-240 have been made, apply power to the unit
by placing the on/off switch to the on position. The on/off switch is located on the
rear panel power entry module.
If an external reference is fitted, verify that the two green LEDs Reference A
Available (1) and Reference B Available (2) are illuminated. This indicates that
the PDU-240 has detected the presence of the external references.
Place the Reference Select Switch (3) in the center (AUTO) position. The green
Reference A Online LED (4) and the AUTO LED (6) should illuminate. This
indicates that the PDU-240 outputs will be driven from Reference A and if
Reference A fails, it will automatically switch to Reference B.
If an internal oscillator is installed, allow 5 - 10 minutes for the initial warm up of
the Pulse reference. The PDU-240 is now ready for operation.
4.2 Selecting the Input Reference
The external pulse source used is selected by the Reference Select Switch (3).
Moving the switch to the left position will select input A as the reference. Moving
the switch to the right position will select input B as the reference. The center
(AUTO) position will use Reference A as the input if it is present and the status
indicator indicates that it is good.
Either one or two internal oscillators may be installed. If one is installed, it is
always installed as Reference A. To operate as a free running standard, leave
the reference select switch in the left position.
4.3 Fault Indicator
The red LED on the front panel indicates that one or more of the outputs has a
low signal. There are four potential causes for this as listed below:
1. There is no input signal or the internal OCXO (if fitted) has failed.
2. Input B has been manually selected and there is no input signal
connected to reference Input B.
3. One or more output buffers have failed.
4. There is a short on an output cable.

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5 Maintenance and Troubleshooting
There is no preventive maintenance required for the PDU-240.
SYMPTOM
POTENTIAL CAUSE
CORRECTIVE ACTION
No signal
outputs
1. There is no input
reference.
2. The Reference Select
switch is set to a channel
with no input
1. Connect the reference
input.
2. Set the selector switch to
auto or to a channel with a
valid input.
Fault light
illuminated
1. One or both of the status
inputs are pulled low
1. Check the status of the
source. Repair the source
or remove the low input to
the status inputs

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6 Calibration
No calibration is required for the PDU-240
NOTE:
The pulse counter MUST be configured to use an external reference
such as a Cesium, Rubidium, or GPS disciplined OCXO as its time-base.
The calibration accuracy of the PDU-240 can only be as accurate as the
reference against which it is calibrated. It should be better than 1x10-10

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7 Drawings
FIGURE
DESCRIPTION
1
PDU-240 Front Panel
2
PDU-240 Rear Panel
3
PDU-240 Mechanical Outline
4
PDU-240 Link Location