Cattron CT24 Series User manual

CT24-9, CT24-17 and
CT24-32 MCU
User Manual
9M02-7608-A001-EN

CT24 MCU
User Manual
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Version 2.0
Revision History
VERSION
DATE
NOTES
1.0
05/2016
Initial Release
2.0
09/2019
Rebranded to Cattron
Added CT24-9-ASO
Any information furnished by Cattron™ and its agents is believed to be accurate and reliable. All specifications are subject to change without notice.
Responsibilityfortheuseandapplication ofCattronproductsrestswiththeendusersinceCattronanditsagentscannotbeawareofallpotentialuses.
Cattron makes no warranties as to non-infringement nor as to the fitness, merchantability, or sustainability of any Cattron products for any
specificor generaluses.CattronHoldings,Inc.,oranyofitsaffiliatesoragentsshallnotbeliableforincidental or consequentialdamagesof any
kind. All Cattron products are sold pursuant to the Terms and Conditions of Sale, a copy of which will be furnished upon request. When used as a
tradename herein, Cattron means Cattron Holdings, Inc. or one or more subsidiaries of Cattron Holdings, Inc. Cattron™, corresponding logos,
and other marks are trademarks or registered trademarksofCattronHoldings,Inc.Othermarksmaybethepropertyofthirdparties.Nothingherein
providesalicenseunderanyCattronoranythirdpartyintellectualpropertyright.

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Contents
1. Introduction...................................................................................................................................................................................6
Terminology .......................................................................................................................................................6
2. Warnings and Cautions ..............................................................................................................................................................7
2.1 General Safety Information................................................................................................................................9
2.2 Intended Use....................................................................................................................................................10
2.3 Improper Use ...................................................................................................................................................10
2.4 Safety Instructions for Assembly/Disassembly ................................................................................................10
2.5 Operation of OCUs and MCUs with Identical System Address........................................................................10
3. General .......................................................................................................................................................................................11
3.1 Radio Transmission .........................................................................................................................................11
3.1.1 Continuous Transmission.............................................................................................................................11
3.1.2 Radio Interference........................................................................................................................................11
3.2 Telegram Security............................................................................................................................................11
3.2.1 Frame Type..................................................................................................................................................11
3.2.2 System Address...........................................................................................................................................11
3.2.3 CRC .............................................................................................................................................................11
3.2.4 Frame Counter.............................................................................................................................................12
3.5 System Parameters..........................................................................................................................................12
4. CT24 MCU Overview................................................................................................................................................................13
4.1 Description.......................................................................................................................................................14
4.1.1 Optional 9-36 VDC Input MCU.....................................................................................................................20
5. Installation...................................................................................................................................................................................21
5.1 General ............................................................................................................................................................21
5.2 Mounting ..........................................................................................................................................................21
5.2.1 Choosing a Mounting Location.....................................................................................................................21
5.3 Interface...........................................................................................................................................................25
5.4 Interface Wiring................................................................................................................................................25
5.5 Safety Critical Interfaces..................................................................................................................................25
5.6 Power and Control Cables Interface ................................................................................................................25
5.7 Determination of Correct Control Circuit Wire Gauge......................................................................................26
5.7.1 For High Duty Cycle Applications.................................................................................................................27
5.7.2 For Low Duty Cycle Applications .................................................................................................................27
5.8 Examples of Wire Sizing..................................................................................................................................28
5.8.1 Low Duty Application (Typical Crane)..........................................................................................................28
5.8.2 High Duty Application (Crane with Multi Select or Machine)........................................................................28
5.8.3 High Duty Maximum Current Application .....................................................................................................28

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5.9 Connection of Wires to Interface Connectors ..................................................................................................28
5.9.1 Interface Connectors....................................................................................................................................28
5.9.2 Overview ......................................................................................................................................................28
5.9.3 Spring Clamp Type Inserting a Wire............................................................................................................29
5.9.4 Spring Clamp Type Removing a Wire..........................................................................................................29
5.9.5 Terminal Specifications................................................................................................................................29
5.9.6 Ferrule Types...............................................................................................................................................29
6. MCU Connections .....................................................................................................................................................................32
6.1 CT24-9-ASO Compatibility with CT24-9............................................................................................................33
6.1 Conduit.............................................................................................................................................................36
6.2 The Controller Machine....................................................................................................................................37
6.3 Control Transformer.........................................................................................................................................37
6.4 Relay Outputs ..................................................................................................................................................37
6.5 Mainline Circuit.................................................................................................................................................37
6.6 Transfer Switch................................................................................................................................................39
6.7 Antenna............................................................................................................................................................40
7. Optional System Features........................................................................................................................................................42
7.1 OCU Automatic Turn-Off..................................................................................................................................42
7.2 Motion Enable Features...................................................................................................................................42
7.2.1 Push To Operate (PTO)...............................................................................................................................42
7.2.2 Push To Enable (PTE) .................................................................................................................................42
7.2.3 Double Jog Enable (DJE) (LRC OCUs only)................................................................................................43
7.2.4 Vigilance.......................................................................................................................................................43
7.3 IR Link..............................................................................................................................................................44
7.3.1 Feature and Benefits....................................................................................................................................44
7.3.2 Features Options..........................................................................................................................................44
7.4 RF Range Control............................................................................................................................................46
7.4.1 Feature and Benefits....................................................................................................................................46
7.4.2 Feature Options ...........................................................................................................................................47
7.4.3 Operating Modes..........................................................................................................................................47
7.4.4 Notes on the Differences between IR and RF Close Start...........................................................................48
7.5 Delayed Shutoff (LRC OCUs only)...................................................................................................................48
7.6 User Authorization............................................................................................................................................49
7.7 Multi Address Capability (MAC).......................................................................................................................49
7.7.1 REQUEST Function.....................................................................................................................................50
7.7.2 RELEASE Function......................................................................................................................................50
7.8 Sub Address Capability....................................................................................................................................50
7.8.1 T-SAC TransKeys ........................................................................................................................................50

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7.8.2 B-SAC..........................................................................................................................................................50
7.9 TDMA...............................................................................................................................................................51
7.10 Frequency Scanning........................................................................................................................................51
7.11 SymmetryLock™..............................................................................................................................................51
7.11.1 Key Value Statements .............................................................................................................................52
7.12 Multi-MCU Talkback.........................................................................................................................................52
7.13 Talkback and LCD Display Resolution.............................................................................................................52
Appendix: Error Codes.....................................................................................................................................................................53
CE Declaration of Conformity..........................................................................................................................................................54

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1. Introduction
This manual includes general information concerning the operation of the radio remote Machine Control Unit
(MCU) series CT24. The information is of a general nature and does not include system-specific data. System-
specific data is provided in the technical documentation accompanying the delivery of the system.
For information pertaining to the matching Operator Control Unit (OCU), please refer to the separate OCU user
manual.
Terminology
The following represents important acronyms and long form names used in this document:
•OCU –Operator Control Unit, historically referred to as a transmitter
•MCU –Machine Control Unit, historically referred to as a receiver
•ASO –Automatic Safety Override; in this context, a fully automatic system shutdown made possible by
the use of safety relays on motion output relays to detect a welded or closed contact when it should be
open
•N/O –SPST Normally Open, Form A
•N/C –SPDT Normally Closed, Form C (BBM)

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2. Warnings and Cautions
WARNING and CAUTION statements are strategically placed throughout all text prior to operating or
maintenance procedures, practices or conditions considered essential to the protection of personnel (WARNING),
or equipment and property (CAUTION). A WARNING and CAUTION applies each time the related step repeats.
Before starting any task, review and understand the WARNINGS or CAUTIONS included in the text. All
WARNINGS and CAUTIONS appearing in this manual are included below.
WARNING
ALL EQUIPMENT MUST HAVE A MAINLINE (ML) CONTACTOR INSTALLED AND ALL
TRACKED EQUIPMENT (I.E., CRANES) MUST HAVE A BRAKE INSTALLED.
THE REMOTE CONTROL SAFETY RELAYS MUST BE CONNECTED TO THE MAINLINE SO
THAT STOP COMMANDS WILL DE-ENERGIZE THE MAINLINE CONTACTOR AND SET THE
EQUIPMENT BRAKE.
FAILURE TO COMPLY WITH THE ABOVE WARNINGS MAY RESULT IN SERIOUS INJURY OR
DEATH TO PERSONNEL AND DAMAGE TO EQUIPMENT.
WARNING
MORE THAN ONE REMOTE CONTROL SYSTEM MAY BE USED AT, AROUND, OR NEARBY
YOUR OPERATING FACILITY. THEREFORE, BEFORE INSERTING A 'TRANSKEY', YOU MUST
INSURE THE CORRECT CODED 'TRANSKEY' IS SELECTED FOR THE DESIRED EQUIPMENT
TO BE OPERATED.
IF THE WRONG 'TRANSKEY' IS INSERTED, OTHER REMOTE CONTROLLED EQUIPMENT
LOCATED AT, AROUND, OR NEARBY YOUR FACILITY MAY BECOME OPERATIONAL.
FAILURE TO COMPLY WITH THE ABOVE WARNINGS MAY RESULT IN UNINTENDED
OPERATION OF REMOTE CONTROLLED EQUIPMENT WHICH IN TURN COULD RESULT IN
SERIOUS INJURY OR DEATH TO PERSONNEL AND DAMAGE TO EQUIPMENT.
WARNING
BEFORE ATTEMPTING TO USE THE REMOTE CONTROL SYSTEM, VERIFY THE TARGET
CRANE OR MACHINE YOU WISH TO OPERATE IS UNDER THE DIRECT COMMAND OF
YOUR OCU. THIS IS ACCOMPLISHED BY OPERATING A NON-MOTION OCU FUNCTION
SUCH AS THE HORN AND OBSERVING THAT THE HORN SOUNDS ON THE TARGETED
CRANE OR MACHINE.
FAILURE TO IMPLEMENT THE ABOVE MAY RESULT IN SERIOUS INJURY OR DEATH TO
PERSONNEL AND DAMAGE TO EQUIPMENT.
!
!
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WARNING
UNLESS SPECIFIED, REMOTE CONTROL SYSTEMS ARE NOT DESIGNED TO INTERFACE
DIRECTLY TO SAFETY CRITICAL BISTABLE MAINTAINED FUNCTIONS (i.e., magnetic circuits,
vacuum circuits, grab, pump motors, fire suppression, etc.).
A PROPER INTERFACE TO SAFETY CRITICAL BISTABLE MAINTAINED FUNCTIONS SHALL
BE INSTALLED, IDEALLY USING A RELAY INTERFACE UNIT.
SHOULD CATTRON SYSTEMS BE INADVERTENTLY CONFIGURED TO INTERFACE
DIRECTLY WITH SAFETY CRITICAL BISTABLE MAINTAINED FUNCTIONS AT YOUR
OPERATING FACILITY, DAMAGE TO EQUIPMENT, SERIOUS INJURY OR DEATH TO
PERSONNEL MAY RESULT.
IT MUST BE FULLY UNDERSTOOD THAT CATTRON WILL NOT BE HELD LIABLE FOR
PERSONAL INJURY, DEATH, EQUIPMENT OR PROPERTY DAMAGE WHICH MAY ARISE
FROM IMPROPER CONFIGURATION OF YOUR REMOTE CONTROL SYSTEM.
WARNING
THE USE OF UNAPPROVED COMPONENTS OR ACCESSORIES IN THE SYSTEMS SOLD BY
CATTRON AND ITS SUBSIDIARIES IS STRICTLY PROHIBITED. UNAPPROVED
COMPONENTS ARE DEFINED AS ANY COMPONENT NOT INSPECTED AND SOLD BY
CATTRON. THIS ALSO INCLUDES ANY COMPONENT MODIFIED FROM ITS INTENDED USE
AND/OR ANY COMPONENT EXHIBITING OBSERVABLE DAMAGE OR DEFECT.
USE OF NON-CONFORMING PARTS, ASSEMBLIES AND ACCESSORIES MAY LEAD TO
INJURY OR DEATH.
WARNING
ONLY PERSONEL TRAINED AND AUTHORIZED BY CATTRON, OR PERSONEL UNDER THE
DIRECT GUIDANCE OF CATTRON TECHNICAL STAFF AND WHILE USING THE
APROPRIATE TOOLS, ARE AUTHORIZED TO CARRY OUT BOARD LEVEL MAINTENANCE
OF THE CT24 MCU.
COMPONENT LEVEL REPAIR BY PERSONEL OTHER THAN CATTRON TECHNICAL STAFF
IS STRICTLY FORBIDDEN.
USE OF NON-CONFORMING PARTS, ASSEMBLIES AND ACCESSORIES MAY LEAD TO
INJURY OR DEATH.
!
!
!

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WARNING
THE REMOTE CONTROL SYSTEM YOU HAVE PURCHASED IS DESIGNED TO STOP IN A
SAFE MODE UNDER A VARIETY OF CONDITIONS. SOME EXAMPLES OF THESE
CONDITIONS ARE EXCESSIVE RADIO SIGNAL INTERFERENCE, LOSS OF BATTERY
AND/OR ELECTRICAL POWER, FAILURE OF CERTAIN COMPONENTS, OPERATION
BEYOND SIGNAL RANGE AND OTHERS. ALTHOUGH CATTRON AND ITS SUBSIDIARIES DO
NOT SPECIFY THE POSITION OF THE OPERATOR WHEN CONTROLLING THE EQUIPMENT,
WE ARE AWARE THAT SOME USERS ARE INSTRUCTED AND TRAINED BY THEIR
EMPLOYER TO RIDE THE EQUIPMENT IN A SAFE MANNER. IT IS IMPERATIVE THAT YOU
ARE PREPARED FOR AN UNPLANNED STOP OF THE EQUIPMENT AT ANY TIME AND DO
NOT PLACE YOURSELF OR OTHERS IN A POSITION WHERE THIS SITUATION MAY CAUSE
YOU TO FALL FROM THE EQUIPMENT. FAILURE TO USE CAUTION MAY LEAD TO INJURY
OR DEATH.
2.1 General Safety Information
•Persons under the influence of drugs, alcohol and/or other medicine that impairs reaction may not
assemble, disassemble, install, put into operation, repair or operate the product.
•All conversions and modifications of an installation or system must conform to the relevant safety
requirements. Only qualified, trained, authorized personnel may perform work on the equipment, in
accordance with the relevant safety requirements.
•In the event of malfunction and/or visible defects or irregularities, the product must be stopped, switched
off, and the relevant master switches also switched off.
WARNING
Observe the statutory regulations and directives applicable for the intended purpose, e.g.:
•Accident prevention regulations
•Safety rules and directives
•Standards
•Generally applicable statutory and other binding regulations for accident prevention and
environmental protection, and general safety and health requirements.
•Keep the operating manual permanently accessible at the place of product use.
•The personnel assigned to work on/with the product must have read and understood this operating
manual and the safety instructions.
•The safety instructions must, if necessary, be supplemented by the user with instructions concerning the
work organization, work sequences, qualified personnel, etc.
•All repairs made during the warranty period must be carried out by the manufacturer or appointed
authorized service center; failure to comply will invalidate the warranty.
•Only trained personnel may perform maintenance and repair on the product.
•All repairs made should be carried out in a suitably clean static-safe environment, free from contaminants
such as metal filings, water, oil, etc.
•It is the user’s responsibility to ensure that the product always operates in good condition and that all
applicable safety requirements and regulations are observed.
•Product modifications may not be carried out without the consent of the manufacturer.
•Original spare parts from the manufacturer must be used.
•Carry out periodic inspections and/or maintenance either required by law or prescribed in the user manual
within the required intervals.
!
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2.2 Intended Use
The product must only be used in good condition, by instructed personnel, and subject to compliance with all
applicable safety and accident prevention regulations. Use only for the intended purpose and according to the
instructions contained within this user manual.
2.3 Improper Use
Ensure compliance with equipment ratings and operate only as intended, in particular:
•Only authorized and trained personnel should open the MCU cover and install/maintain
•Ensure all supplies to the equipment are isolated before installation/maintenance
•Check that power supply voltage/frequency data is correct
•Do not misuse or exceed operating specifications
•Ensure daily and periodic maintenance routines are observed
CAUTION
Damage to the device:
The unit is rated at IP65. For environments harsher than this, use an appropriate secondary
enclosure.
Neglecting the above can result in danger for life and limb and/or cause physical damage to the
product or the environment.
2.4 Safety Instructions for Assembly/Disassembly
Only trained and qualified persons may perform installation/maintenance work.
Note: Ensure suitable transient protection devices are fitted to controlled electrical relays or valves. Ensure
correct wiring of the crane’s main contactor and the manual radio transfer switch.
•Isolate the system from the electrical power in accordance with the applicable regulations.
•Observe user-specific regulations.
•Only use suitable tools.
•Secure the installation area.
2.5 Operation of OCUs and MCUs with Identical System Address
To ensure safe operation, OCUs and MCUs are uniquely paired by way of a unique system address. This system
address will only be assigned once by the manufacturer.
CAUTION
Conflict of Addresses:
The user must ensure that the system address is used as designed and intended for a single
system.
The system address is marked on the master TransKey; the OCU and intended MCU address
must match.
In the event of a breach of this undertaking, the user is liable for any resulting damage/loss and
shall indemnify the manufacturer against all third-party liability claims.
!
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3. General
With an OCU and a matching MCU, a machine such as a crane or vehicle can be remotely radio controlled,
avoiding the need for a wired connection between the human interface and the controlled device. A number of
different control elements are integrated into the OCU housing so that commands to the device securely encode
into a radio transmission. The MCU is then able to receive this transmission, securely decode these commands,
and provide suitable interfaces to drive the machine.
3.1 Radio Transmission
The transmission between the OCU and MCU is performed by means of radio communication. With regard to the
actual radio frequency that is used, there are several radio frequency bands available.
A specific RF frequency band and channel will often have been selected prior to delivery of the system.
Depending on the frequency band, a certain number of RF channels are available.
The OCU and MCU must operate on the same RF channel in order to be able to communicate
3.1.1 Continuous Transmission
Typically, transmission is continuous and the MCU uses this as part of the information required to maintain the
safety relays in an active state. If the MCU does not receive a valid telegram in this mode for a certain period of
time, it automatically turns off; i.e., safety relays and command relays open. Depending on the application, the
time varies from 0.5 s to 2.0 s.
In order to ensure optimum communication between the OCU and the MCU, ideally operate the OCU with line of
sight to the MCU antenna at all times. Avoid total shielding of the signal path by metallic and other solid
obstructions.
In some configurations, the MCU may be configured to operate safely in the absence of RF signal, much as a
safety PLC will do. Such applications are strictly defined.
3.1.2 Radio Interference
Signals from other RF-emitting sources might interfere with the radio communication between the OCU and MCU.
If the radio link is affected by these sources, changing the RF channel or even the RF band might be necessary.
3.2 Telegram Security
The transmitted telegram contains several security features.
3.2.1 Frame Type
Each message has an 8-bit message type identifier that is unique to the equipment in use.
3.2.2 System Address
This system uses a 24-bit addressing scheme, with each OCU/MCU pair sharing a common, unique system
address. This system address is contained in every telegram sent by the OCU and is checked by the MCU every
time a RF signal is received. The MCU processes a command only when the address in the telegram and the
address stored in the MCU match. This is a safety measure to ensure that the MCU will act only upon its assigned
OCU.
3.2.3 CRC
The telegram is checked for integrity using a 16-bit CRC; frames containing mismatched CRC will be rejected.

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3.2.4 Frame Counter
Each message has an 8-bit embedded frame counter that changes on every data frame; this prevents frozen data
and data frame hacking.
3.5 System Parameters
The system parameters, including the system address and the selected RF channel, are set by programming the
TransKey. This is a removable radio frequency identification device (RFID) located inside the OCU and MCU. It is
programmed by the manufacturer.
Note: Please refer to the separate 'Configuration Data' documents for the specific system parameter settings
of your system.

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4. CT24 MCU Overview
Portable Remote Control (PRC) systems offer the safety and dependability required for industrial control
applications, including those with reversing motor control such as overhead cranes, conveyors, etc. The MCU
described in this manual incorporates high-performance microprocessors and an advanced design that is
compliant with all standard global requirements.
This MCU can be operated with one or more operator control units (OCUs). Basically, in its most simple form, the
OCU is a radio transmitter and the MCU is a radio receiver. A radio frequency (RF) receiver, decoder and relay
interface contained in the MCU is under the direct control of the operator with the OCU.
The CT24 MCU is supplied in three different size enclosures: the smaller CT24-9, the medium CT24-17 and the
larger CT24-32 (some variations exist for each with fewer relays).
The standard MCU operates from a 110–240 VAC input supply and is shown below:
Figure 1: Typical CT24 MCU Component Layout (CT24-17 shown here)

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The enclosure output interface to the controlled machine is handled by relays rated for typical machine interfaces.
Each relay has an adjacent ‘STATUS’ LED that illuminates when the relay is energized.
Note: These relay ‘STATUS’ LEDs are only visible when the cover has been removed from the MCU.
Individual relay outputs are routed to the controlled equipment via a terminal strip.
When a fault condition is detected, the main contactor safety relays and all other outputs are disabled.
Note: The CT24-9-ASO, CT24-17 and CT24-32 main contactor safety relays KO-S and KO-M are each
protected with a fuse. The CT24-9 only has a single fuse. If the OCU is communicating with the MCU
and the machine Mainline Contactor fails to energize, these fuses should be checked for continuity.
Just like the OCU, MCUs use a removable 'TransKey' to define and enable the appropriate operating parameters.
Note: OCU and MCU TransKeys must not be swapped. The OCU (transmitter) TransKey is black. The MCU
(receiver) TransKey is yellow. Swapping TransKeys will result in OCU/MCU fault indications and the
system will not operate.
4.1 Description
The receiver may be supplied with either an internal or external antenna. To ensure optimum communication, the
transmitter and the receiver should be installed with line of sight between the antennas of both units. Any
shielding by metallic constructions should be avoided.
If the receiver is installed inside a metallic enclosure, a detached antenna is required.

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Figure 2: CT24-9 MCU
This MCU has two main contactor safety relays with one fuse and one pair of terminals, seven N/O relays and two
C/O relays. The following items are identified in Figure 2:
1. Status LEDs on micro board
2. TransKey inserted in slot inside enclosure
3. Seven N/O function relays
4. Terminal main input voltage
5. Fuse main input
6. Removable terminal strip for function relays
7. Fuse for main contactor safety relays
8. Terminal strip for main contactor safety relays
9. Two main contactor safety relays
10. Two C/O function relays

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Figure 3: CT24-9-ASO MCU Printed Circuit Assembly
This MCU has an enhanced safety design with separated main contactor circuits and some upgraded function
relays resulting in two main contactor safety relays with two fuses and two pairs of terminals, five N/O relays, two
N/O safety relays and two C/O safety relays. The following items are identified in Figure 3:
1. Five N/O function relays
2. Two N/O function safety relays
3. Two C/O function safety relays
4. Main contactor safety relays
5. Fuses for main contactor safety relays
6. Terminals for main contactor safety relays
NB: If you are replacing a CT24-9 relay board with a CT24-9-ASO relay board, it will be necessary to link the two
safety main contactor relays in series with an additional link wire between the two terminal blocks 6a and 6b.

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Figure 4: CT24-17 MCU
The following items are identified in Figure 4:
1. Transkey
2. Status LEDs
3. Terminal main input voltage
4. Fuse main input
5. Function relay plug in terminal strips
6. Fuses for main contactor safety relays
7. Terminal strip for main contactor safety relays

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Figure 5: CT24-32 MCU
NB: Optional HAN style connector shown fitted
The following items are identified in Figure 5:
1. Status-LEDs
2. TransKey
3. Terminal main voltage
4. Fuse mains
5. Removable terminal strips for function relays
6. Fuses for main contactor safety relays
7. Terminal strip for main contactor safety relays

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As illustrated in the following figure, all CT24 MCUs have five externally visible LED indicators on the front cover
that display the current system status to the operator. The status/fault messages associated with each LED are
described in Table 1.
Figure 6: MCU System Status LEDs (all CT24 versions)
Table 1: MCU External Status/Fault LED Messages
MCU EXTERNAL
LED INDICATORS
DESCRIPTION
1. Power On
Illuminates orange when the MCU receiver has voltage
2. Scan Mode
Flashes red/orange in Scan Mode
Not used when system is configured for fixed frequency
3. RF Reception
Illuminates green when valid data from the OCU is received and both safety
relays are energized
Illuminates orange if valid data from the OCU is received and the safety relays are
de-energized
Illuminates red if data from another OCU (with invalid address) is received
4. Command
Illuminates green when commands are received from the OCU (normal condition)
5. Fault indication
Blinks red when the MCU detects a fault (refer to the Appendix on Error Codes for
the blink sequence and the corresponding fault messages)

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Referring to Figure 7, an additional processor status LED indicator is mounted on the MCU processor board and
may be viewed by removing the MCU front cover. This LED blinks orange if the receiver does not detect a
transmitter and green if valid messages are received. In addition, if the second processor detects a fault, this LED
blinks red.
Figure 7: MCU Status and Fault LEDs
4.1.1 Optional 9-36 VDC Input MCU
An optional 9-36 VDC input MCU, Part Number 1MCU-7608-A103, is available. This MCU is identical to the
standard MCU except that the power supply on the relay board is changed.