Comtech EF Data Radyne RCU101 User manual

Part Number TM055Revision 2.2
IMPORTANT NOTE: The information contained in this document supersedes all previously
published information regarding this product. This manual is subject to change without prior notice.
RCU101
1:1 Converter Protection Switch
Installation and Operation Manual
Part Number TM055
Revision 2.2
May,2002

Copyright ©2002 Comtech EF Data. All rightsreserved. Printed in the USA. ComtechEFData,
2114 West 7thStreet,Tempe, Arizona 85281 USA, 480.333.2200, FAX: [phone]

RCU101 1:1 Protection Switch Warranty Policy
TM055 - Rev. 2.2 ii
RADYNE COMSTREAM WARRANTY POLICY
WARRANTY AND SERVICE
Radyne ComStream (Seller) warrants the items manufactured and sold by Radyne ComStream to be free
of defects in material and workmanship for a period of two (2) years from date of shipment Radyne
ComStream's obligation under its warranty is limited in accordance with the periods of time and all other
conditions stated in all provisions of this warranty.
This warranty applies only to defects in material and workmanship in products manufactured by Radyne
ComStream. Radyne ComStream makes no warranty whatsoever concerning products or accessories not
of its manufacture.
Repair, or at Radyne ComStream's option, replacement of the Radyne ComStream products or defective
parts therein shall be the sole and exclusive remedy for all valid warranty claims.
WARRANTY PERIOD
The applicable warranty period shall commence on the date of shipment from Radyne ComStream's
facility to the original purchaser and extend for the stated period following the date of shipment. Upon
beginning of the applicable Radyne ComStream warranty period, all customer's remedies shall be
governed by the terms stated or referenced in this warranty. In-warranty repaired or replacement products
or parts are warranted only for the remaining unexpired portion of the original warranty period applicable
to the repaired or replaced products or parts. Repair or replacement of products or parts under warranty
does not extend the original warranty period.
WARRANTY COVERAGE LIMITATIONS
The following are expressly not covered under warranty:
1. Any loss, damage and/or malfunction relating in any way to shipping, storage, accident, abuse,
alteration, misuse, neglect, failure to use products under normal operating conditions, failure to use
products according to any operating instructions provided by Radyne ComStream, lack of routine care and
maintenance as indicated in any operating maintenance instructions, or failure to use or take any proper
precautions under the circumstances.
2. Products, items, parts, accessories, subassemblies, or components which are expendable in normal
use or are of limited life, such as but not limited to, bulbs, fuses, lamps, glassware, etc.

Warranty Policy RCU101 1:1 Protection Switch
TM055 - Rev. 2.2 iii
Radyne ComStream reserves the right to revise the foregoing list of what is covered under this warranty.
WARRANTY REPLACEMENT AND ADJUSTMENT
Radyne ComStream will not make warranty adjustments for failures of products or parts which occur after
the specified maximum adjustment period. Unless otherwise agreed, failure shall be deemed to have
occurred no more than seven (7) working days before the first date on which a notice of failure is received
by Radyne ComStream. Under no circumstances shall any warranty exceed the period stated above
unless expressly agreed to in writing by Radyne ComStream.
LIABILITY LIMITATIONS
THIS WARRANTY IS EXPRESSLY IN LIEU OF AND EXCLUDES ALL OTHER EXPRESS AND IMPLIED
WARRANTIES, INCLUDING BUT NOT LIMITED TO WARRANTIES OF MERCHANTABILITY AND OF
FITNESS FOR PARTICULAR PURPOSE, USE, OR APPLICATIONS, AND ALL OTHER OBLIGATIONS
OR LIABILITIES ON THE PART OF RADYNE COMSTREAM, UNLESS SUCH OTHER WARRANTIES,
OBLIGATIONS, OR LIABILITIES ARE EXPRESSLY AGREED TO IN WRITING BY RADYNE
COMSTREAM.
All obligations of Radyne ComStream under this warranty shall cease in the event its products or parts
thereof have been subjected to accident, abuse, alteration, misuse or neglect, or which have not been
operated and maintained in accordance with proper operating instructions.
IN NO EVENT SHALL RADYNE COMSTREAM BE LIABLE FOR INCIDENTAL, CONSEQUENTIAL,
SPECIAL OR RESULTING LOSS OR DAMAGE OF ANY KIND HOWSOEVER CAUSED. RADYNE
COMSTREAM’S LIABILITY FOR DAMAGES SHALL NOT EXCEED THE PAYMENT, IF ANY,
RECEIVED BY RADYNE COMSTREAM FOR THE UNIT OR PRODUCT OR SERVICE FURNISHED OR
TO BE FURNISHED, AS THE CASE MAY BE, WHICH IS THE SUBJECT OF CLAIM OR DISPUTE.
Statements made by any person, including representatives of Radyne ComStream, which are inconsistent
or in conflict with the terms of this warranty, shall not be binding upon Radyne ComStream unless reduced
to writing and approved by an officer of Radyne ComStream.
WARRANTY REPAIR RETURN PROCEDURE
Before a warranty repair can be accomplished, a Repair Authorization must be received. It is at this time
that Radyne ComStream will authorize the product or part be returned to the Radyne ComStream facility
or if field repair will be accomplished. The Repair Authorization may be requested in writing or by calling:
Radyne ComStream Corporation
3138 E. Elwood St.
Phoenix, Arizona 85034 (USA)
Attn: Customer Support
Phone: [phone] Fax: [phone]
Any product returned to Radyne ComStream for examination must be sent prepaid via the means of
transportation indicated as acceptable to Radyne ComStream. Return Authorization Number must be
clearly marked on the shipping label. Returned products or parts should be carefully packaged in the
original container, if possible, and unless otherwise indicated, shipped to the above address.
NON-WARRANTY REPAIR
When a product is returned for any reason, Customer and its shipping agency shall be responsible for all
damage resulting from improper packing and handling, and for loss in transit, not withstanding any defect
or nonconformity in the product. By returning a product, the owner grants Radyne ComStream permission
to open and disassemble the product as required for evaluation. In all cases, Radyne ComStream has
sole responsibility for determining the cause and nature of failure, and Radyne ComStream's
determination with regard thereto shall be final.

RCU101 1:1 Protection Switch Record of Revisions
TM055 - Rev. 2.2 iv
RCU101 1:1 Protection Switch
Installation and Operation Manual
TM055 - Record of Revisions
Radyne ComStream Corporation is constantly improving its products and therefore the information in this
document is subject to change without prior notice. Radyne ComStream Corporation makes no warranty
of any kind with regard to this material, including but not limited to the implied warranties of
merchantability and fitness for a particular purpose. No responsibility for any errors or omissions that may
pertain to the material herein is assumed. Radyne ComStream Corporation makes no commitment to
update nor to keep current the information contained in this document. Radyne ComStream Corporation
assumes no responsibility for use of any circuitry other than the circuitry employed in Radyne ComStream
Corporation’s systems and equipment.
Revision
Level Date Reason for Change
1 7-15-96 Initial Release
2 11-28-96 Added Illustrations of front and rear panels, new interconnection
diagram, added schematics, updated Operation and Maintenance
2.1 2-7-97 Updated Fault Status connector, updated specifications
2.2 5-31-02 Added Appendix B

RCU101 1:1 Protection Switch Table of Contents
TM055 - Rev. 2.2 v
Table of Contents
1.0 Introduction….…..……………………………………………………………………………………… 1-1
2.0 Installation Requirements..…...……………………………………………………………………… 2-1
2.1 Unpacking..………..…………………………………………………………………………………… 2-1
2.1.1 Removal and Assembly..…………………………………………………………………………… 2-1
2.2 Mounting Considerations.…..………………………………………………………………………… 2-1
2.3 Cabling..………………………………………………………………………………………………… 2-1
2.4 Hardware Interface..…………………………………………………………………………………… 2-4
2.4.1 Protection Switch Interface Connector……………………………………………………………2-4
2.4.2 Switch Fault/Status Connector…….……………………………………………………………… 2-5
2.4.3 RCU101 RF and IF Rear Panel Connectors..……………………………………………………2-5
2.4.4 Interfaces Common to the Converters…………………………………………………………… 2-6
2.4.5 Operator Serial I/O.………………………………………………………………………………… 2-6
2.4.6 Up/Downconverter Equipment RS485 Port..…..…………………………………………………2-7
3.0 Operation (Definitions)…….……………………………………………………………………………3-1
3.1 Switch Logic………..……………………………………………………………………………………3-1
3.2 Manual/Auto Mode Selection Switch.….…………………………………………………………….. 3-1
3.3 Switch LEDs…………………………………….……………………………………………………… 3-2
3.4 Troubleshooting and/or Replacing a Faulted Converter……………………………………………3-2
4.0 Periodic Maintenance…………..………………………………………………………………………4-1
Appendix A - Technical Specifications….…………………………………………………………………A-1
Appendix B - RCU101 Block Diagram, Configuration Drawings and Schematics……………………B-1

TM054 - Rev. 2.2 vi

RCU101 1:1 Protection Switch Description
TM055 - Rev. 2.2 Page 1-1
Section 1 - RCU101 1:1 Protection Switch Description
1.0 Introduction
The Radyne ComStream RCU101 1:1 Protection Switch Unit provides automatic circuit
restoration for one online frequency Up or Downconverter. The switch provides complete
isolation of primary and backup converters by providing transfer switching of both the RF and IF
signal paths. Converter fault and circuit restoration is initiated from the summary fault contacts
of the online converter. Upon clearing of the fault in the online converter, or after replacement
of the online converter, the switch can be directed to restore the operation to the online
converter (or the converter that is selected as the ‘online’ unit). An RS485 Equipment interface
between the converters allows the backup converter to ‘learn’ the gain and frequency settings of
the online unit.
Figure 1-1. RCU101 1:1 Protection Switch Front Panel

Description SFC4200 C-Band Downconverter
Page 1-2 TM054 - Rev. 2.2

RCU101 1:1 Protection Switch Installation
TM055 - Rev. 2.2 Page 2-1
Section 2 - Installation
2.0 Installation Requirements
The RCU101 is designed to be installed within any standard 19-inch equipment cabinet or rack,
and requires 1 rack unit of mounting space (1.75 inches) vertically, and 17-inches of depth.
Including cabling, a minimum of 20-inches of rack depth is required. The unit can be placed on
a table or suitable surface if required.
There are no user-serviceable parts or configuration settings located inside the RCU101
chassis. There is a potential shock hazard internally at the power supply module. DO
NOT open the RCU101 chassis under any circumstances.
⇒ CAUTION: Before initially applying power to the unit, it is a good idea to disconnect
the transmit output from the operating satellite ground station equipment. This is
especially true if the current RCU101 configuration settings are unknown, where incorrect
setting could disrupt existing communications traffic.
2.1 Unpacking
The RCU101 was carefully packaged to avoid damage and should arrive complete with the
following items for proper installation:
1. RCU101 1:1 Protection Switch
2. One cable set per paragraph 2.3.
3. Installation and Operation Manual.
2.1.1 Removal and Assembly
If using a knife or cutting blade to open the carton, exercise caution to ensure that the blade does
not extend into the carton, but only cuts the tape holding the carton closed. Carefully unpack the
unit and ensure that all of the above items are in the carton. The RCU101 is shipped fully-
assembled and does not require removal of the covers for any purpose in installation.
2.2 Mounting Considerations
When mounted in an equipment rack, adequate ventilation must be provided. The ambient
temperature in the rack should be between 10°and 35°C, and held constant for best equipment
operation. The air available to the rack should be clean and relatively dry.
2.3 Cabling
The RCU101 comes complete with all the cabling required to interface with two Upconverters or
Downconverters. Refer to Figure 2-1 to become familiar with the rear panel connectors on the
RCU101. Figure 2-2 shows a typical interconnection between two Upconverters and the
RCU101. The list of supplied cables is as follows:
P/N Description QTY
CA/3291 RS485 Equipment Interface Cable 1
CA/3292 B/U Switch Interface Cable 2

Installation RCU101 1:1 Protection Switch
Page 2-2 TM055 - Rev. 2.2

RCU101 1:1 Protection Switch Installation
TM055 - Rev. 2.2
Page 2-3

Installation RCU101 1:1 Protection Switch
Page 2-4 TM055 - Rev. 2.2
CA/3293 RF Cable, 1:1 Switch 2
CA/1961-003 IF Cable, 1:1 Switch 2
Routing of the cables between the two converters and the switch is depicted in Figure 2-2. Note
that the RF/IF cabling included with the switch does not include cables to other panels in the
rack.
2.4 Hardware Interfaces
Hardware interfaces between the online and backup converter and the switch equipment include
the RF interface, IF interface, Switch Interface, and Equipment RS-485 interface. In addition to
the above, the operator has access to all converter equipment in the system including the switch
via the operator RS-232 interface on the converter.
2.4.1 Protection Switch Interface (Primary & Backup) Connector (J1 & J2)
The protection switch interface connector is a DB 15-pin connector that connects each converter
with the backup switch unit. This cable is not daisy-chained between converters but serves as a
direct link for each converter in the configuration whether they are the primary converter or the
backup unit. This interface finds use in both the 1:1 and 1:N configuration type switches. The
pinout of the switch is as follows:
J1 B/U Switch Interface
J1 Pin# DB 15 Nomenclature Description Controller AS/3048
J7
1 N.O Form-C contact summary fault normally open contact 1
5 N.C. Form-C contact summary fault normally closed contact 9
9 COM Form-C contact summary fault common contact 2
13 GND 10
2 +15V Or’d Diode Or’d +15 Vdc from converter 3
6 FCB1 Fault Code bit 1 11
10 FCB2 Fault Code bit 2 4
14 FCB3 Fault Code bit 3 12
3 FCB4 Fault Code bit 4 5
7 IDB1 IDBit1 13
11 IDB2 IDBit2 6
15 IDB3 IDBit3 14
4 IDB4 IDBit4 7
8 INT O Interrupt 15
12 RMT 8

RCU101 1:1 Protection Switch Installation
TM055 - Rev. 2.2
Page 2-5
The ID Bits provide information to the converter that tells the converter which slot (either primary
or backup) the converter is plugged into. The addresses are as follows:
IDB4 IDB3 IDB2 IDB1 Position
1 0 1 0 Backup
1 0 1 1 Primary
2.4.2 Switch Fault/Status Connector (J11)
The RCU101 Redundancy Control Unit contains a summary Fault/Status connector that is
available to the equipment operator for the purpose of monitoring the summary fault status of
both converters as well as the individual status of the converters. The pinouts of this 15-pin D
SUB connector are as follows:
J11 DB15 Description
1 Primary Converter Summary Fault Relay Com.
2 Primary Converter Summary Fault Relay N.C.
3 Primary Converter Summary Fault Relay N.O.
9 Backup Converter Summary Fault Relay Com.
4 Backup Converter Summary Fault Relay N.C.
5 Backup Converter Summary Fault Relay N.O.
10 Switch Online Status Com. (B active/A inactive)
11 Switch Online Status N.C. (Primary Online) - continuity
12 Switch Online Status N.O. (Backup Online) - continuity
13 Remote Primary (Active Low)
14 Remote Backup (Active Low)
6 Switch Summary Fault Relay Com. (Active on OK/Inactive on Fault)
7 Switch Summary Fault Relay N.C.
8 Switch Summary Fault Relay N.O.
15 Ground
The primary and backup summary fault relay contacts provide fault indications to flow through
the switch into one common connector. In addition, the two Form-C summary fault contacts on
the test fault connector on the rear of the RCU101 provide a Form-C closure to indicate which
converter is presently online. Continuity of these contact closures implies online status for the
indicated converter.
2.4.3 RCU101 RF and IF Rear Panel Connectors
The following paragraphs describe the RF and IF connectors located on the rear panel of the
RCU101.
2.4.3.1 J3 RF Primary
The RF Primary connector goes to the RF port of the primary converter. This connection is
made via the supplied semi-rigid cable with the RCU101 system. If the primary converter is

Installation RCU101 1:1 Protection Switch
Page 2-6 TM055 - Rev. 2.2
online, this port will be connected to the RF In/Out port (J4).
2.4.3.2 J4 RF In/Out
The RF In/Out port is the user interface to the RCU101 protection switch system. This
connection is an SMA F-type. The conversion to the N-type connector should be made at the
rack interface panel. If the system requires interface to an N-connector cable, an SMA-to-N
adapter is recommended.
2.4.3.3 J5 RF Termination 50-Ohm
The 50-ohm RF termination terminates the RF output of a redundant upconverter system or the
input of a redundant downconverter system for the converter that is in standby or faulted mode.
By removing the termination, access to the RF port of the standby converter can be obtained.
2.4.3.4 J6 RF Backup
The RF Backup connector is a type SMA-F that routes the RF signal of the backup converter to
the transfer switch in the RCU101. This connection is made via the supplied semi-rigid cable
assembly that is included with the RCU101.
2.4.3.5 J7 IF Termination 75-Ohm
The IF Termination is a 75-Ohm BNC type termination for the IF port of the converter that is in
standby mode. By removing the 75-Ohm termination, the operator can gain access to the IF port
of the converter that is currently in standby mode.
2.4.3.6 J8 IF Prime
This BNC-F connector goes to the IF connector of the primary converter. This connection is
made via the supplied IF cable assembly with the RCU101.
2.4.3.7 J9 IF In/Out
This BNC-F connector is the user IF interface to the redundant converter system.
2.4.3.8 J10 IF Backup
The IF Backup BNC-F connector connects to the IF port of the backup converter. This
connection is made with the IF cable assembly supplied with the RCU101 System.
2.4.4 Interfaces Common to the Converters
The RS485 equipment interface and the operator serial I/O interface found on the converter
hardware both play a role in the operation of the switch and are included here for continuity. For
further information, please refer to the converter manual for more information on these two
interfaces.
2.4.5 Operator Serial I/O (J8 on Converter Rear Panel)
Through the Operator Serial Port, the operator can gain access to all of the control features of
the converter. This enables the remote operator to configure the switch, set the gain and
frequency of the converter and interrogate status of the converter.
The Operator Serial Port is a DB 9-pin female connector at the rear of the converter. This port
provides serial interface that can be configured as either a RS232, RS422 or RS485 interface.
This port allows the user to remotely control all of the features outlined in the Serial Protocol
(Appendix B). The serial port comes configured as an RS-232 Serial port for DCE unless

RCU101 1:1 Protection Switch Installation
TM055 - Rev. 2.2
Page 2-7
indicated otherwise. The pinout of the D sub 9-pin socket connector configured for RS232 or
RS422/485 is as follows:
Operator Serial I/O Connector (Rear Panel)
J8 DB 9 Pin# RS232 RS422/485 AS/3048 J10
1 N/C RXData\ 1
2 TXData TXData 3
3 RXData RXData 5
4 DTR -- to pin 6 DTR -- to pin 6 7
5 GND Gnd 9
6 DSR -- to pin 4 DSR -- to pin 4 2
7 RTS -- to Pin 8 RTS -- to Pin 8 4
8 CTS -- to pin 7 CTS -- to pin 7 6
9 N/C TXData\ 8
NOTE: In order to obtain these signals at the output connector, the jumper configuration on the
AS/3048 Controller PWB must have been performed as outlined in Appendix C. A summary of
jumper selections is as follows:
Configuration JP4-1 JP4-2 JP4-3 JP4-4 JP4-5 JP4-6 JP3 JP5 JP6 JP7 JP8
RS232 OUT OUT OUT OUT IN IN OUT OUT IN OUT OUT
RS422 IN IN IN IN OUT OUT OUT* OUT OUT OUT IN
RS485 IN IN IN IN OUT OUT OUT* OUT OUT OUT IN
485 1/2 DPLX IN OUT OUT IN OUT OUT OUT* IN OUT IN IN
*Receiver terminations for twisted pair RS422/485 can be optionally terminated at 120 ohms by
installing JP3. Factory-supplied cables for multiple converter "daisy chain" operation are
terminated at the cable ends.
2.4.6 Up/Downconverter Equipment RS485 Port (J6 on Converter Rear Panel)
An equipment multi-drop, full-duplex, bi-directional RS485 Interface allows communication
between converters. Because the RS485 interface uses a master/slave (talker/listener)
configuration, the converter that is designated the backup converter will automatically be

Installation RCU101 1:1 Protection Switch
Page 2-8 TM055 - Rev. 2.2
established as the master. Under normal RS485 protocol, the master will poll a specific slave
by address and only then will the slave unit respond. The swapping of Transmit Data and
Receive Data is accomplished in the inter-converter cable as the hardware interface is identical
for all converters.
J6 DB 9-Pin Description 10 Pin AS/3048
1 GND 1
2 SRCLK 3
3 No Connect 5
4 TXNot 7
5 TX 9
6 SRDAT 2
7 No Connect 4
8 RXNot 6
9 RX 8
The signals on pins 2 and 6 of the DB9 connector are the clock and data of the I-squared bus
which is an optional interface employed in the 1:8 (RCU108) protection systems only.

RCU101 1:1 Protection Switch Operation
TM055 - Rev. 2.2 Page 3-1
Section 3 - Operation
3.0 Definitions
The nomenclature used throughout this manual is meant to imply various roles that each (up or down)
converter assumes depending upon the state of the converters and the settings of the protected
converter system. These descriptions are as follows:
AProtected Converter System consists of the primary converter, backup converter, and the
RCU101 switch and required interface cables.
The Primary Converter is the converter that is connected to the Primary Port on the Switch.
The Backup Converter is the converter that is connected to the Backup Port on the Switch
The Online Converter can be either the primary or backup converter.
3.1 Operation
The 1:1 protection switch unit provides automatic restoration for one online converter. An RS485
equipment interface allows the backup converter to ‘learn’ the frequency and gain settings of the
primary converter. The learning process is initiated by the user, via the backup converter. By
entering the Utilities menu from the front panel of the backup converter, it will allow the user to initiate
the learning process. The backup converter will indicate whether the learning process was successful.
If the process was not successful, the converter will indicate the learning process failed. Refer to the
converter manual for more details.
(MENU) for next menu
(ENTER) for Learn Mode
<ENTER>
Automatic Learning in Process Automatic Learning
Failed
Automatic Learning <MENU>
Successfully Completed Reason For
Failure
3.1 Switch Logic
The RCU101 uses the output of the Form-C relay in the converter to determine what action to take.
In the following descriptions, it is assumed that the switch is in Auto mode and that the other converter
is not faulted. (If the switch were in Manual mode, no switching would take place).
The Fault N.O logic level is derived from the normally open contact of the summary fault Form-C
relay in the converter. The converter, when clear of any and all faults, asserts the summary fault
relay to the not faulted state and the contact is open. A fault in the converter, turning the converter
off, failure of the converter power supply, or disconnecting the switch interface cable will cause the
relay to close. Upon detection of this event, the switch will toggle control and data to the other
converter.
Once the fault in the faulted converter is cleared, the converter will reset the summary fault relay and
the contact will again be open. Upon detection of this event, the switch will place the converter in
standby, so that it can be placed online in the event that the other converter fails. The switch will not
automatically switch back to the original online converter.
The following truth table illustrates this switching logic. A ‘1’ in this table indicates that the
corresponding converter is faulted.

Operation RCU101 1:1 Protection Switch
Page 3-2 TM055 - Rev. 2.2
Primary Backup Action
0 0 No action. Whoever was online, stays online.
1 0 Backup converter is placed online.
0 1 Primary converter is placed online.
1 1 No action. Whoever was online, stays online.
In addition to providing the switching logic, the RCU101 provides each converter with 4 ID bits that tell
the particular converter whether it is the primary or backup converter. The ID bits are as follows:
ID Bits Meaning
1010 Backup
1011 Primary
3.2 Manual/Auto Mode Selection Switch
The Manual/Auto mode selection switch is located on the front of the RCU101 and is used in the
following manner:
When the switch is placed to the far left (PRI), the primary converter is placed online and will stay
online even if it faults.
When the switch is placed to the far right (BU), the backup converter is placed online and will stay
online even if it faults.
When the switch is placed in the middle position, it will automatically switch to the backup when a
fault is detected in the online converter.
If the front panel switch is accidentally left in the manual mode, the RCU101 can be placed in the auto
mode remotely by sending a Manual Command followed by an Auto Command to the converter that
was deselected by the front panel switch. (See the applicable converter manual for more details).
3.3 Switch LEDs
The are two sets of identical switch LEDs, one set for the primary converter and one for the backup
converter. Their meanings are the same.
Online LED - The Online LED indicates that the corresponding converter has been placed
online by the switch.
Standby LED - The Standby LED indicates that the corresponding converter is in Standby.
Fault LED - The Fault LED indicates that the corresponding converter is currently faulted.
Manual LED - The MANUAL LED indicates that the converter has been manually selected and will
stay there.
3.4 Troubleshooting and/or Replacing a Faulted Converter
Prior to testing or replacing a faulted converter it is strongly recommended that the mode selection
switch be set to manually select the converter that is currently online. Once the faults on the faulted
converter have been cleared (or the converter has been replaced), the converter can be placed in the
standby by moving the mode selection switch back to the center, thus placing the switch in auto
mode.
Note: If the switch is left in the middle (auto) position while tests are being performed on a converter
that is not faulted, and the online converter faults, the switch will automatically toggle control and data

RCU101 1:1 Protection Switch Operation
TM055 - Rev. 2.2
Page 3-3
to the converter under test. This can result in unwanted operation when the converter under test is
not at the same frequency or gain levels as the online converter.