Micronor MR380-1-3 User manual

© Copyright 2013-2021, Micronor LLC., USA
MR380-1-3
Universal DIN Rail Controller
For Use with MR38X Series
Fiber Optic Signaling Sensors
Instruction Manual
Document: 98-0380-01
Revision E dated 5/7/2021
MICRONOR LLC.
900 Calle Plano, Suite K
Camarillo, CA 93012
USA
[phone]
[e-mail]
www.micronor.com
For Support in Europe:
MICRONOR AG
Pumpwerkstrasse 32
CH-8105 Regensdorf
Switzerland
[phone]
[e-mail]
www.micronor.ch
Notice of Proprietary Rights
The design concepts and engineering details embodied in this manual, which are the property of MICRONOR
LLC., are to be maintained in strict confidence; no element or detail of this manual is to be spuriously used, nor
disclosed, without the express written permission of MICRONOR LLC. All rights are reserved. No part of this
publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means,
electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from
MICRONOR LLC.

MR380-1-3 Instruction Manual
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Revision History
Revision
Date
Notes
A
12/11/2013
•Initial release
B
7/13/2015
•
Added 50/125 fiber pigtail option
•Controller design upgraded to Universal and will work
with both 50/125 and 62.5/125 multimode fiber
C
10/15/2015
•Update with new Camarillo address and tel/fax numbers
C1
03/09/2016
•Style Update
D
10/17/2016
•
E-Stop part number change, MR380 to MR387
•Added Single Mode option
•Added reference to IECEx Test Report
•Added MR380-2-2 Switch Contoller
•
Added Declaration of Conformity
D1
12/1/2016
•Corrected SIL typo, is SIL1/PLc
D2
3/2/2017
•Added Single Mode Declaration of Conformity to
Appendix
D3
5/18/2017
•Remove 850nm Multimode Option
D4
9/27/2019
•Single Mode MR387/MR381 maximum loss specification
increased to 5dB
•
Combined SM/MM Declaration of Conformity added
E
5/7/2021
•
Updated text and logos to reflect change to Micronor
LLC., a division of Photon Control
•Updated MR380-1-3 and MR387 E-Stop System
Functional Safety and Declaration of Conformity
•Added MR380-1-3
Controller minimum system loss
budget of 23dB, maintained typical system loss budget
of 25dB
•Removed MR380-1-2 and MR380-2 Controllers
•Removed MR381 E-Actuator and MR385 Foot Pedal
•
Updated figures

MR380-1-3 Instruction Manual
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Table of Contents
1. Product Description ................................................................................5
MR387 Fiber Optic Emergency Stop Switch ...................................................................5
MR386 Fiber Optic Microswitch......................................................................................6
Fields of Application .......................................................................................................7
Features ..........................................................................................................................7
2. Standard Contents ..................................................................................8
3. MR380-1-3 Controller Installation and Operation ...................................9
Mounting the MR380-1-3 Controller Module..................................................................9
Connecting the MR380-1-3 Controller Module...............................................................9
Mounting the MR387 E-Stop Switch .............................................................................10
MR380-1-3 Installation .................................................................................................. 11
3.4.1. Electrical Connections............................................................................................11
3.4.2. MR380-1-3 and MR387 E-Stop System Start-Up & Performance Check ................. 12
4. Troubleshooting....................................................................................13
Potential Issues & Solutions ..........................................................................................13
Damaged in Shipment ..................................................................................................14
5. Warranty Information ............................................................................15
6. Specifications ........................................................................................16
MR380-1-3 Controller Module ......................................................................................16
MR387 Emergency Stop Switch ....................................................................................17
7. Theory of Operation..............................................................................19
The “Universal” Controller ............................................................................................19
Functional Block Diagram .............................................................................................20
8. Application Notes .................................................................................21
Determining System Loss Budget when Chaining Multiple Switches ............................ 21
Triggering Multiple Controllers with a Single E-Stop .................................................... 22
9. Reference Documents...........................................................................23
MR380-1 Controller Reference Drawing........................................................................23
MR387 E-Stop Reference Drawing................................................................................23
MR380 Series Declaration of Conformity ...................................................................... 23

MR380-1-3 Instruction Manual
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Table of Figures
Figure 1. MR387 Emergency Stop Switch with MR380-1-3 Controller..........................5
Figure 2. Complete E-Stop Functional System Overview .............................................6
Figure 3. MR386 Microswitch with MR380-1-3 Controller ............................................6
Figure 4. MR380-1-3 Mounting Options: DIN Rail Mount versus Chassis Mount..........9
Figure 5. Panel Cut Out Dimensions and Assembly Hierarchy of E-Stop Switch ........10
Figure 6. E-Stop Switch Orientation Interchangeable when Mounting into Optical Block 10
Figure 7. Front Panel Outputs of MR380-1-3 Controller. Error! Bookmark not defined.
Figure 8. Controller with E-Stop: Power On (Left) and E-Stop Depressed (Right).......12
Figure 9. LC Loopback MR380-1-3 Controller Check .................................................14
Figure 10. Block Diagram for a MR380-1-3 Controller System ...................................20
Figure 11. Example E-Stop System Using Three MR387 E-Stop Switches ..................21
Figure 12. Example System With One MR387 E-Stop Triggering Two Remote MR380-1-3
Controllers..........................................................................................................22

MR380-1-3 Instruction Manual
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1. Product Description
MR387 Fiber Optic Emergency Stop Switch
Figure 1. MR387 Emergency Stop Switch with MR380-1-3 Controller
The MR387 Fiber Optic Emergency Stop Switch paired with MR380-1-3 Controller provides a new,
innovative emergency signaling detection that can be deployed in hazardous environments and
over very long distances. The E-Stop Switch employs a photo interrupt scheme operating over a
duplex multimode or single mode optical link that allows for reliable signal detection and
implements a known default failure state.
The optical signal levels are rated inherently safe, allowing the sensor to be safely deployed in any
type of explosive atmosphere or hazardous location. The entire fiber optic sensor system has a
generous system loss budget, enabling long distance systems, complex routing and daisy chaining
of multiple switches.
Depressing the switch interrupts the optical signal and the controller provides both Double Pole
Double Throw (DPDT) relay contacts and digital outputs for signal and control. The controller will
indicate if there is a broken fiber connection or depressed switch in the system which provides
increased safety margin over electrical emergency switches. The controller will always default to
the emergency state when the switch is depressed, in case of a broken or disconnected fiber, or
due to loss of power to the controller unit.
Multiple E-Stops may be wired in series to one controller as long as all optical losses fall within the
optical loss budget of the controller used.
Figure 2provides a complete functional overview of the emergency switch system.

MR380-1-3 Instruction Manual
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Figure 2. Complete E-Stop Functional System Overview
MR386 Fiber Optic Microswitch
Figure 3. MR386 Microswitch with MR380-1-3 Controller
The MR386 Fiber Optic Microswitch paired with the MR380-1-3 Controller provides a new,
innovative signaling detection that can be deployed in difficult, hazardous environments and over
very long distances. The Microswitch employs a photo interrupt scheme operating over a duplex
62.5/125μm fiber optic link that allows for reliable signal detection. This provides the same
mechanical attributes typically associated with ubiquitous electrical microswitches. It has
mechanical tactile feedback when the switch toggles – essential when precise switching points
need to be set.

MR380-1-3 Instruction Manual
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There are two switch materials. The completely non–metallic version is designed to operate within
an MRI environment where high magnetic fields would interfere with any electronic switch. The
switch may be safely used within the MRI bore because it is immune to the magnetic field as well
as invisible to the imaging process. It is also an ideal switch for deployment in highly corrosive
atmospheres. Meanwhile, the industrial version employs a metallic non-magnetic spring and can
work over a wider temperature range. The optical signal levels are rated inherently safe, allowing
the system to be safely deployed in various explosive atmospheres or hazardous locations.
In addition, there are two optical circuit configurations. The Normally Open (NO) layout
corresponds to an optical circuit that is open until the microswitch is depressed; the Normally
Closed (NC) layout corresponds to an optical circuit that is closed until the microswitch is
depressed.
Fields of Application
•Hazardous Environments: Oil & gas mining/extracting, refining
•Medical: MRI environment
•Energy Distribution: Switches may be deployed next to high voltage lines
Features
•EMI/RFI Immune
•Immune to High Voltage Lines and Lightening
•ATEX classified Inherently Safe for EPL Mb/Gb/Gc/Db/Dc applications
•Wide System Loss Budget
•Complex Routing Capability
•Long Distance Signaling without Interference
•Double Pole Double Throw (DPDT) Relay Output
•Digital Signal Out
•Universal DIN Rail Controller, compatible with 50/125 µm, 62.5/125 µm and 9/125 µm links
•E-Stop Switch available with 50/125µm, 62.5/125µm and 9/125µm fibers
•Multiple E-Stop Switches can be Wired in Series

MR380-1-3 Instruction Manual
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2. Standard Contents
MR380-1-3 Controller Module:
•MR380-1-3 Controller Module
•Phoenix Terminal Block (1879599) inserted as part of unit
•Instruction Manual (this document, one soft copy supplied with each shipment)
MR387 series Sensor:
•MR387 sensor (confirm pigtail and/or connector interface as ordered)

MR380-1-3 Instruction Manual
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3. MR380-1-3 Controller Installation and Operation
Mounting the MR380-1-3 Controller Module
The controller unit mounts on DIN rails as well as a single mounting clip. Both mounting schemes
are shown below in Figure 4.
Figure 4. MR380-1-3 Mounting Options: DIN Rail Mount versus Chassis Mount
Connecting the MR380-1-3 Controller Module
An LC Duplex optical cable is used to interconnect the sensor and controller. The sensor
incorporates a 3m optical pigtail (or alternate length as specified by customer). If a longer
connection to the controller is required, then an extension cable having an LC Duplex connector
may be used.
Remove the LC Duplex connector's dust cap(s) and open the external shutter of the controller.
When inserting the LC Duplex connector, there should be a positive click when the connector is
engaged properly. Avoid repeated fiber optic disconnects to reduce likelihood of surface
contamination.

MR380-1-3 Instruction Manual
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Mounting the MR387 E-Stop Switch
When mounting the E-Stop switch into a panel, provide a cut-out as dimensionally shown below
in Figure 5 and the Mechanical Reference Drawing in Section 9.2.
Refer to Figure 6 below for switch orientation. Secure panel-mount switch with all appropriate
designations and requirements.
Figure 6. E-Stop Switch Orientation Interchangeable when Mounting into Optical Block
Figure 5. Panel Cut Out Dimensions and Assembly Hierarchy of E-Stop Switch
Mushroom Push
Mounting
Panel Lock Washer
Gasket
2-56 x 3/16
Panhead Philips

MR380-1-3 Instruction Manual
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MR380-1-3 Installation
3.4.1. Electrical Connections
Figure 7. Front Panel Outputs of MR380-1-3 Controller
The table above depicts the pinouts for the MR380-1-3 controller, and the state of each
terminal when an E-stop switch is on or off. For powering the controller, +24 VDC is supplied
to terminal 1 and grounded using terminal 2. For typical E-stop operation, connect to
terminals 5 and 6 or terminals 8 and 9.
The contact on the controller module uses a Phoenix Contact screw terminal. For more
information, consult Controller specifications given in Section 6.1. If connectors are lost or
damaged, contact Micronor Sales for replacement details.
MR380-1-3 Fiber Optic Controller State Table
Terminal
Description
1 +24 VDC Power Supply
Module
Powered
Module Not
Powered
2 Ground Input
Switch
ON
Switch
OFF
Switch
ON/OFF
3
Digital 24V Normally High
LOW
HIGH
-
4
Digital 5V Normally High
LOW
HIGH
-
5
Normally Closed Relay Contact 2
OPEN
CLOSED
OPEN
6
Common Relay Contact 2
-
-
-
7
Normally Open Relay Contact 2
CLOSED
OPEN
CLOSED
8
Normally Closed Relay Contact 1
OPEN
CLOSED
OPEN
9
Common Relay Contact 1
-
-
-
10
Normally Open Relay Contact 1
CLOSED
OPEN
CLOSED

MR380-1-3 Instruction Manual
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3.4.2. MR380-1-3 and MR387 E-Stop System Start-Up & Performance Check
Connect +24VDC supply and ground to the designated terminals on the controller module.
Verify that the ‘POWER’ LED (green) is illuminated. If the E-Stop Switch is not connected, do
so at this time and verify that the ‘EMERGENCY ON’ LED (red) is as shown below:
E-Stop Switch
‘Power’
LED
‘Emergency
ON’ LED
24V Digital
Out
5V Digital
Out
Relay Contacts
Not Depressed
ON
OFF
Hi
> +20V
Hi
> + 4V
NO=Open
NC=Closed
Depressed
ON
ON
Low
< +1V
Low
< +0.5V
Polarization Change
NO=Closed
NC=Open
If the Emergency Switch and Controller LEDs are not illuminated as shown below, see Section
4Troubleshooting for help.
Figure 8. Controller with E-Stop: Power On (Left) and E-Stop Depressed (Right)

MR380-1-3 Instruction Manual
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4. Troubleshooting
The following are potential issues and recommended solutions when troubleshooting the MR380-
1-3 fiber optic system. For issues not listed, please contact Micronor Sales.
Potential Issues & Solutions
If the Instructions do not rectify the problem, then contact Micronor Sales for further assistance.
Function
Symptom
Instructions
‘Power’
Green LED
Not
illuminated
when
controller
powered
•Verify solid electrical connection between wires and screw
terminal for both +24VDC and GND.
•Verify controller module power supply is +24VDC with a current
output of at least 80mA.
‘Emergency ON’
Red LED
(Using MR387
Only)
Illuminated
when E-Stop
not depressed
•
Check if emergency switch is ‘On’ when depressed. If so, reset
switch and verify ‘Emergency ON’ is now off.
•Verify optical link cabling is properly connected and undamaged.
•Verify that the fiber optic system does not exceed system loss
margin specifications. Measure the output power using a power
meter set at 1300nm. It should read between -8.5dBm to -6.5dBm
whe
n using 62.5/125µm or 50/125µm MM fiber, or between
-9.5dBm to -6.5dBm when using 9/125µm SM fiber.
•Clean all fiber optic connector surfaces using appropriate cleaning
materials.
+5V and +24V
Digital Outputs
No high
voltage output
•
Verify
solid electrical connection between wires and screw
terminal for Digital Out and GND.
•
Verify that the controller module is properly powered with
+24VDC and grounded.
•
Verify emergency switch is connected and 'Emergency ON’ is off.
Relay
Switching
failure
•Verify solid electrical connection between wires and screw
terminal for NO2, NC2, CM2, NO1, NC1, CM1
•
Verify that the controller module is properly powered with
+24VDC and grounded.
•Verify E-Stop Switch is connected and “Emergency ON’ is off.
•Verify when switch is depressed the controller will electro-
mechanically switch the state of the relay resulting in a faint ‘click’
sound.
Damaged
Sensor
E-Stop
•
Verify controller module outputs optical power by connecting LC
loopback directly from one LC connector to the other, shown in
Figure 9
. ‘Power’ should be illuminated and ‘Emergency ON’
should be OFF.
•Verify undamaged fiber with visual fault finder.
•Verify that the switch loss is less than the Optical Insertion Loss
specification of the switch sensor using an optical power meter.
•Clean fiber optic surfaces on the switch using the appropriate
cleaning materials.

MR380-1-3 Instruction Manual
Page 14 of 29
Figure 9. LC Loopback MR380-1-3 Controller Check
Damaged in Shipment
In the event of a damaged instrument, write or call your nearest MICRONOR office in the U.S. A.
Please retain the shipping container in case reshipment is required for any reason.
If you receive a damaged instrument you should:
1) Report the damage to your shipper immediately.
2) Inform MICRONOR
3) Save all shipping cartons.
Failure to follow this procedure may affect your claim for compensation.

MR380-1-3 Instruction Manual
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5. Warranty Information
Warranty
MICRONOR LLC. warrants this product to be free from defects in material and workmanship for a
period of 1 (one) year from date of shipment. During the warranty period we will, at our option,
either repair or replace any product that proves to be defective.
To exercise this warranty, write or call your local MICRONOR LLC. representative, or contact
MICRONOR LLC. headquarters. You will be given prompt assistance and return instructions. Send
the instrument, transportation prepaid, to the indicated service facility. Repairs will be made and
the instrument returned transportation prepaid. Repaired products are warranted for the balance
of the original warranty period, or at least 90 days.
Limitations of Warranty
This warranty does not apply to defects resulting from unauthorized modification or misuse of any
product or part. This warranty also does not apply to Fiber Optic Connector interfaces, fuses or
AC line cords. This warranty is in lieu of all other warranties, expressed or implied, including any
implied warranty of merchantability of fitness for a particular use. MICRONOR LLC. shall not be
liable for any indirect, special or consequent damages.
Contact Information:
Micronor LLC Phone [phone]
900 Calle Plano, Suite K Email sales@micronor,com
Camarillo, CA 93012 URL www.micronor.com
USA
For Europe:
Micronor AG Phone [phone]
Pumpwerkstrasse 32 Email [e-mail]
CH-8015 Regensdorf URL www.micronor.ch
SWITZERLAND

MR380-1-3 Instruction Manual
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6. Specifications
For additional clarification of parameters related to Functional Safety, Laser Safety, Explosive
Atmospheres and CE Marking, consult Micronor document 93-0380-01, Declaration of Conformity.
MR380-1-3 Controller Module
Functional States
As Applies to MR387 E-Stop Sensor
Normal RESET (Up Position) Red LED is OFF
Digital 5V and 24V Outputs=HI
Relay NC contacts=Closed, NO contacts=Open
ACTIVATED (Down Position)
Broken Fiber, Loss of Optical Signal,
or Controller Failure
Red LED is ON
Digital 5V and 24V Outputs=LOW
Relay NC contacts=Open, NO contacts=Closed
Digital Outputs
5V Logic
5 VDC/2k Ω Load Max
24V Logic
24 VDC/2k Ω Load Max
Relay Contacts
2x Form C (COM-NO-NC)
Switching Power Rating
60 W / 62.5 VA
Contact Material
AgNi, Gold Covered
DC Rating 75 V @ 0.75A; 24 V @ 2A
AC Rating
50 V @ 1A; 24 V @ 2A
Optical Class I Eye Safe
Compatible Fibers Multimode OM1 62.5/125 or OM2 50/125
Single Mode OS1 9/125 or SMF-28
System Loss Budget
Minimum 23dB, Typical 25dB
Maximum Optical Link Length Distance is a function of user’s system loss budget which is the total round-trip loss
of all optical link components - sensor(s), connectors, splices and cable segments.
Consult Application Note AN118 for more information.
Contact Micronor for longer distance applications.
Interface
NOTE: Electrical connections shall not exceed 3 meters.
Electrical
10-pin Screw Terminal, 30-14 AWG (Phoenix Mating Plug 1803659)
Optical
LC-Duplex, 9/125 SM transmit fiber, 62.5/125 MM receive fiber
Power Supply
+24 VDC, <80 mA input
Functional Safety
For MR387 E-Stop Sensor + MR380-1-3 Universal Controller
ISO 13849
Category 2
MTTFd
4.14 E+06 hours (473.1 years)
Performance Level (PL)
PL=c
Safety Integrity Level (SIL) SIL=1
Explosive Atmospheres
Inherently Safe Optical Radiation
Ex Classification Controller shall be installed in non-hazardous location only
Power supply to Controller shall be current limited to 200mA or less
IECEx Test Report (ExTR) GB/CML/ExTR 16.0105/00 (Multimode Controllers)
ATEX EPL Mb/Gb/Gc/Db/Dc
IEC Ex
EPL Mb/Gb/Gc/Db/Dc
NEC
Exempt

MR380-1-3 Instruction Manual
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Environmental Performance
Temperature/Humidity
-5°C to +55°C (23°F to +131°F), 0-95% RH, Non-Condensing
Ingress Protection
IP50
Physical Attributes
Mounting
35mm DIN Rail
Housing
11.4 x 8.9 x 3.2 cm (4.5 x 3.5 x 1.25 inches)
Weight
230 g (8.1 oz)
Specifications subject to change without notice
MR387 Emergency Stop Switch
Functionality
ISO 13850 ISO 13850 defines the characteristics and requirements for a traditional
electromechanical E-
STOP switch. The MR380 Sensor/Controller integrates the
definition of purpose and functionality only.
Functional States
MR380-1-3 Universal Controller Output States
Normal RESET (Up Position) Red LED is OFF
Digital 5V and 24V Outputs=HI
Relay NC contacts=Closed, Relay NO contacts=Open
ACTIVATED (Down Position)
Broken Fiber, Loss of Optical Signal,
or Controller Failure
Red LED is ON
Digital 5V and 24V Outputs=LOW
Relay NC contacts=Open, Relay NO contacts=Closed
Functional Safety
For MR387 E-Stop Sensor + MR380-1-3 Universal Controller
ISO 13849
Category 2
MTTFd4.14 E+06 hours (473.1 years)
Performance Level
PL=c
Safety Integrity Level SIL=1
Optical Interface
Interface Duplex LC for pigtailed sensors, MR387-XX-YY where YY is pigtail length in meters
ODVA IP-LC connector receptacle, MR387-XX-D00 sensors in housing
Insertion Loss For calculating System Loss Budget:
MR387-2X-XX, IL=2.5dB max (2dB typical), 62.5/125 OM1 MM Fiber
MR387-3X-XX, IL=5.0dB max (3dB typical), 9/125 OS1 SM Fiber
MR387-5X-XX, IL=3.5dB max (3dB typical), 50/125 OM2/OM3 MM Fiber
Consult Application Note AN118 for guidance on determining system loss budget
and maximum distance
Explosive Atmospheres
Inherently Safe, Simple Mechanical Device
EX Classification Inherently safe, simple mechanical device when used with MR380 Controller
IECEx Test Report GB/CML/ExTR 16.0105.00/00
ATEX EPL Mb/Gb/Gc/Db/Dc
EAEU/GOST EPL Mb/Gb/Gc/Db/Dc
IEC Ex EPL Mb/Gb/Gc/Db/Dc
North America Exempt, non-electrical
Environmental
Temperature/Humidity
-40°C to +65°C (-40°F to +150°F), 0-95% RH, Non-Condensing

MR380-1-3 Instruction Manual
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Ingress Protection
Pigtail Version=IP61, Panel Mount Housing=IP65
Mechanical
Housing
Aluminum body, anodized finish
Durability
100,000 operations min.
Physical
Housing Dimension
Consult Mechanical Reference Drawing
Mounting
Consult Mechanical Reference Drawing
Unit Weight
Sensor with 5 meter pigtail, 240 g (8.5 oz)
Specifications subject to change without notice

MR380-1-3 Instruction Manual
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7. Theory of Operation
The “Universal” Controller
The MR380-1-3 Controller is designed to be universally compatible with any standard fiber optic
cabling. This is accomplished through the design of its transmit and receive fibers.
In fiber optics, coupling two fibers of different core diameters is only permitted when the core of
the receiving fiber is the same size or larger than that of the transmitting fiber. For example,
transmitting from OS1 9/125µm single mode fiber to OM1 62.5/125µm or OM2 50/125 multimode
fiber does not produce any losses since the core diameter expands from 9µm to 62.5µm or 50µm.
Conversely, transmitting from OM1 or OM2 fiber to OS1 fiber causes significant losses and is
unacceptable as the core of the receiving fiber is smaller than that of the transmitting fiber.
However, if the receiving fiber is only slightly smaller than the transmitting fiber, there is a smaller
loss that can be built into the system loss budget. For example, transmitting from OM1 fiber
(62.5µm core) to OM2 fiber (50µm core) produces a loss of approximately 1.2dB, which is not a
problem in most situations.
In the MR380-1-3 controller, the transmit fiber is OS1 9/125µm single mode fiber. Since the core
of the fiber is smaller than any other standard fiber, no losses are produced at this connection, no
matter which standard fiber the rest of the system uses. And, at the other end, the controller’s
receive fiber is OM1 62.5/125µm multimode fiber. Similarly, no losses are produced at the receive
connection because the OM1 fiber is larger than any standard fiber the rest of the system might
use.
As a result, the MR380-1-3 controller is compatible with any standard fiber, hence its designation
as a universal controller. Despite this designation, users should use the same fiber throughout their
system to avoid complications and simplify future alterations.

MR380-1-3 Instruction Manual
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Functional Block Diagram
A functional block diagram is shown in Figure 10, showing the switch sensor, optical link and
controller module. The switch is connected to the controller by a duplex fiber optic cable of readily
available 50/125µm or 62.5/125µm multimode fiber or 9/125µm single mode fiber. The controller’s
9/125µm single mode transmit fiber guides steady optical power from a near-IR light source to the
optical switch. Then, a 62.5/125µm multimode receive fiber returns the light relaying if the switch
is open or closed.
Controller
Figure 10. Block Diagram for a MR380-1-3 Controller System
The light source power is held constant under normal operating conditions allowing for a known
system loss budget when designing a system. Additionally, the optics within the switch are
designed to couple maximum light back into the receive fiber enabling the ability to create long
distance systems and chain multiple switches.
Next, the optical power is identified by the photodetector and translated into a logic signal
depending on the power level. The photodetector operates with an active low signal scheme
which provides a known failure state. The controller then interprets events such as broken fiber,
poor connection, high loss or a depressed switch as a failure or ‘EMERGENCY ON’.
The photodetector outputs a logic signal to the remaining logic circuitry which then interprets high
or low levels for the +24V and +5V digital outputs.