Johnson Controls IFC-200 Reference guide

IFC-200 Technical Manual 444
Hardware Installation Section
Technical Bulletin
Issue Date 1293
© 1993 Johnson Controls, Inc. 1
Order No. 444-040
IFC-200 Hardware Installation Procedures
Hardware Installation Procedures Page 5
● General 5
- Backbox Mounting 5
● Power Supplies 6
- DC Power Output Connections 7
- AC Power Connections 7
- Battery Power 7
● Output Circuits 8
- Indicating Appliance Circuits 8
- Releasing Circuits 8
● Standard Relays 9
● Remote Printers 9
- Installation 10
- Printer Configuration 10
- PRN-3 Setup Paper Feed Advance 11
- Keltron Printer Option 12
● CRT-1 Configuration 12
- Function Key Programming 14
● Wiring the Signaling Line Circuit 14
- Isolator Modules 14
- Monitor Modules 15
- Control Modules 15
- Intelligent Detectors 15
- Device Capacity 15
- SLC Resistance Measurement 16
- Isolator Module Operation 20
- SLC Shield Termination 21

2 Hardware Installation—IFC-200 Hardware Installation Procedures
● Isolator Module 23
● M500MJ Monitor Module 23
- SLC Connections 23
- NFPA Style B Initiating Device Circuit 24
- NFPA Style D Initiating Device Circuit 24
- Test Switch 24
● M501MJ Monitor Module 24
- NFPA Style B Initiating Device Circuit 25
● M502MJ 25
- SLC Connections 25
- NFPA Style B Initiating Device Circuit 25
- NFPA Style D Initiating Device Circuit 26
● Control Module 30
- SLC Connections 30
- NFPA Style Y Indicating Appliance Circuit 30
- NFPA Style Z Indicating Appliance Circuit 30
- Indicating Appliance Power 31
- Test Switch 31
- SLC Connections 31
- Contact Connections 31
● Addressable Manual Pull Station 34
- BGX-101L Installation 34
● Intelligent Detectors 35
- Installation 35
● Optional Modules 36
- Optional Module Installation 36
- RTM-8 Option Module 36
● NR45-24 Remote Battery Charger 39
- Connecting the Primary Power Source 39
- Connecting the Secondary Power Source 39

Hardware Installation—IFC-200 Hardware Installation Procedures 3
Supply Calculations Page 43
● AC Branch Circuit 43
● Main Power Supply 43
- Smoke Detectors 43
- Standby Current Load on Batteries 45
- Four-Wire Detectors 45
- Alarm Current Load on Batteries 45
- Calculating Necessary Battery Size 45
Wire Requirements 47

4 Hardware Installation—IFC-200 Hardware Installation Procedures

Hardware Installation—IFC-200 Hardware Installation Procedures 5
Hardware Installation
Procedures
This IFC-200 Hardware Installation Procedures Technical Bulletin is
divided into three major sections. The Hardware Installation Procedures
section contains step-by-step instructions to help you install the hardware
related to the IFC-200 Fire Control System. The Supply Calculations
section helps you determine the required current, current loads, and power
to support the IFC-200. Specific wiring information for each circuit in the
system is found in the Wire Requirements section. Read this document
before attempting to install the IFC-200 hardware.
1. Carefully unpack the system and check for shipping damage.
2. Mount the cabinet in a clean, dry, vibration-free area where extreme
temperatures are not encountered. The area should be readily
accessible with sufficient room to easily install and maintain the
panel.
3. Locate the top of the cabinet approximately five feet above the floor
with the hinge mounting on the left.
4. Determine the number of conductors required for the devices to be
installed.
5. Pull the required conductors into the box through the knockout
provided.
All wiring should be in accordance with the National and/or Local codes
for fire alarm systems.
1. Remove the main PC board assembly by unscrewing the four screws
in the corners of the board. Set the board aside in a safe, clean place.
Avoid static discharge, which may damage the board.
2. Mark and pre-drill the four mounting bolts using the dimensions
shown in Figure 1.
3. Install two upper fasteners in wall with screw heads protruding.
4. Using upper keyholes, mount the backbox over the two screws.
Tighten the screws.
5. Install the lower two screws.
6. When location is dry and free of construction dust, reinstall the main
PC board.
General
Backbox
Mounting

6 Hardware Installation—IFC-200 Hardware Installation Procedures
1.00 14.5
12.5
0.5
9.5 16.0
200bckbx
Mounting Holes
Primary Power
120 VAC
Low Voltage
Wiring
Figure 1: IFC-200 Backbox Mounting
Note: Insert all cables from the side of the cabinet. Do not insert wiring
from the back of the cabinet. Note the entry locations of primary
120 VAC power and low voltage wiring above.
!
CAUTION: Damage may occur when removing and/or
inserting cards, modules, or interconnecting cables
while this unit is energized. Several different
power sources can be connected to this panel.
Disconnect all power sources before servicing.
Power Supplies

Hardware Installation—IFC-200 Hardware Installation Procedures 7
All DC power outputs are power-limited.
High Ripple Regulated Power
24 VDC power for indicating appliances
TB1 Terminal 1 (+) and 2 (-).
Note: This power is unsuitable for all
RS-485 annunciation devices,
except the ACM-8R.
1.0 amps standby
2.25 amps alarm
Non-resettable Power
24 VDC filtered, regulated,
non-resettable power can be
drawn from TB1 Terminals 3 (+)
and 4 (-). This power is suitable
for all RS-485 annunciation
devices. 0.50 amps
4-wire Smoke Detector Power
24 VDC filtered, regulated,
resettable power for 4-wire smoke
detectors can be obtained from TB1
Terminals 5 (+) and 6 (-). 0.50 amps
dcpowr
T
B
1
1 2 3 4 5 6
+ - + - + -
Figure 2: DC Power Output Connections
Primary power required for this panel is 120 VAC, 50/60 Hz, 3.0 amps.
Overcurrent protection for this circuit must comply with Article 760 of the
National Electrical Code (NEC) and/or local codes. Use 14 AWG or
larger wire with 600 volt rating.
AC Power Battery
Power
acbatpwr
+
_
Figure 3: AC Power Connections and Battery Power
Observe polarity when connecting the battery. Connect the battery cable
to J3 on the main board using the plug-in connector provided. An MTA
connector tool is required. Refer to Figure 1 in the IFC-200 System
Description Technical Bulletin in this manual for the location of J3. See
the Supply Calculations section of this document to calculate the correct
battery rating.
!
CAUTION: Sulfuric acid in batteries can cause severe burns to the
skin and eyes and can destroy fabrics. If contact is
made with sulfuric acid, immediately flush skin or
eyes with water for 15 minutes and seek immediate
medical attention.
DC Power Output
Connections
AC Power
Connections
Battery Power

8 Hardware Installation—IFC-200 Hardware Installation Procedures
The IFC-200 provides four indicating appliance circuits (Style Y only).
Each circuit is capable of producing 2.25 amps of current at 24 VDC.
Total current drawn from these, as well as any other panel DC power
outputs, cannot exceed 5.0 amps. Use UL Listed 24 VDC indicating
appliances only. Circuits are supervised and power-limited. See
Figure 23 for a list of recommended compatible indicating appliances.
Any or all of these circuits may be used as a releasing circuit by
programming it for RELEASE CKT. See the Releasing Applications
section of the IFC-200 Applications Technical Bulletin in this manual for
more information, including a list of compatible solenoid valves.
T
B
2
B+ B- B+ B- B+ B- B+ B-
1 2 3 4 5 6 7 8
+ -
+ -
+ -
Style Y Indicating Appliance Circuit (Supervised and Power-limited)
Polarized Bell
Polarized Strobe
Polarized Horn
4.7K, 1/2 W (Part No. 71252, UL Listed)
(Supervisory Voltage is 2-3 VDC)
Releasing Circuit
(Supervised and Power Limited)
Dummy Load
All Unused
Circuits 4.7K, 1/2 W
Note: Indicating circuit polarity is shown in the
alarm
state.
tb2conn
Circuit 1 TB2 1 and 2
Circuit 2
Circuit 3
Circuit 4
TB2 3 and 4
TB2 5 and 6
TB2 7 and 8
Figure 4: Circuit Connections
Output Circuits
Indicating
Appliance
Circuits
Releasing
Circuits

Hardware Installation—IFC-200 Hardware Installation Procedures 9
The IFC-200 provides a set of Form-C alarm contacts and a set of Form-C
trouble contacts rated for 2.0 amps at 30 VDC (resistive). The panel also
provides a Form-A supervisory contact rated for 2.0 amps at 30 VDC
(resistive). These contacts are derated to 0.5 amps at 30 VAC.
T
B
3
NO C NO NC C NO NC C
tb3conn
1 2 3 4 5 6 7 8
SUPV ALARM TROUBLE
Figure 5: Relay Connections
The PRN-3 Remote Printer provides a hardcopy printout of all status
changes within the system and time-stamps the printout with the current
time of day and date. The PRN-3 provides 80 columns of data on standard
9 inch by 11 inch tractor-feed paper.
3 2 17
TX REF RX REF OUT OUT IN IN A B B+- A+- B- A-
T
B
4
T
B
5
T
B
6
Plug this DB-25 connector into the
RS-232 printer port.
Connect CRT-1 pin 3 to TB4 TX.
Connect CRT-1 pin 7 to TB4 REF.
Connect CRT-1 pin 2 to TB4 RX.
PRN-3
prn3conn
PRN-3
IFC-200
System Common (-)
IFC-200, TB1-2, or Enclosure
Figure 6: Remote Printer Connections
Standard
Relays
Remote Printers

10 Hardware Installation—IFC-200 Hardware Installation Procedures
Note: The RS-232 printer interface may also be used with EDP-listed
equipment, such as personal computers, to monitor the IFC-200 for
supplementary purposes.
Since the IFC-200 is not the receiving unit in a proprietary system, its use
is optional from a standards compliance standpoint. Remote printers
require 120 VAC, 50/60 Hz primary power. A secondary power source
(battery backup) is not provided; the use of a separate Uninterruptible
Power Supply (UPS), UL Listed for Fire Protection Signaling is
recommended.
The IFC-200 and PRN-3 connect via an RS-232 interface. A custom cable
must be assembled for connection to the printer’s RS-232 port.
Refer to the documentation supplied with the PRN-3 for instructions on
the printer’s menu controls. Set the printer’s options as listed in Table 1.
Table 1: PRN-3 Printer Options
Under the Menu Area:
Character Density 10 CPI
Character Presentation
Character Set Standard
Italic No
Proportional No
Slashed Zero Yes
Courier ISO/PC/Epson 0
National Character 11 (E-US ASCII)
Line Density 6 LPI
Paper Form 11
Skip Over Fold 0.5
Printer Options
Paper Options No Option
Selected Paper Path Push Tractor
Ribbon Options No Option
Left Margin 1
Right Margin 80
Horizontal Tabs 25
No Vertical Tabs Set
Top Margin Top of Form
Bottom Margin 10.5 Inches
Vertical Alignment 12-1/72 Inches
Under the Technical Listing Area:
Auto PrintPrint Commands CR
CR Implies LF No
Continued on next page . . .
Installation
Printer
Configuration

Hardware Installation—IFC-200 Hardware Installation Procedures 11
Under the Technical Listing Area: (Cont.)
Line Overflow CR+LF
Paper Handling
Autoview 3 Sec.
No Autoquicktear
Communication Setup
Buffer Large
Data Bits 7
Parity Even
Stop Bit 1 Stop
Baud Rate 2400
Protocol XON/XOFF
Wake Up Mode On Line: Yes Menu Concealed: Yes
Emulation Mode 3 (ANSI + EPSON FX-105)
Escape Character ESC
Technical Setups
L/R Adjustment 0
Paper Mode Text On
Continuous Form 0-1/72 Inch
Sheet Feeder Rear Tray 0-1/72 Inch
Sheet Feeder Front Tray 0-1/72 Inch
Single Sheet 0-1/72 Inch
When the PRN-3 printer receives an alarm or trouble message from the
control panel, the printer faceplate may hide the message. If this happens,
the printer needs to be configured by adding a one inch printer advance
selection to the printer’s internal setup. This selection advances the paper
up one inch if the printer does not receive additional alarm and/or trouble
messages within three seconds.
To configure the printer correctly, modify the PRN-3 printer software
setup as indicated below.
1. Power down the PRN-3.
2. Press and hold the local switch (fourth faceplate switch from the left)
and power the printer back up.
3. Release the local switch. The MENU LED illuminates.
4. Press the LF-FF key (third key from the left).
5. Using the left/right arrow keys (first and second switches from the
left) move the print head under “Technical Listings.”
Note: Moving the print head to the extreme right or left moves the
software selection back one step. A printed selection does not
appear on the paper.
PRN-3 Setup
Paper Feed
Advance

12 Hardware Installation—IFC-200 Hardware Installation Procedures
6. Press the Set key (third key from the left). All printer parameters list
automatically at this point.
7. At the “Technical” heading, use the left/right arrow keys to move the
print head over the “Menu” heading.
8. Press the Set key.
9. Use the left/right arrow keys to position the printer head over the
“Paper Handling” heading.
10. Press the Set key.
11. Use the left/right arrow keys to move the print head under the “3s”
selection.
12. Press the Set key.
13. Press Local.
Note: Current shipments of the PRN-3 have been modified to include this
software selection.
The IFC-200 may also be used with a Keltron printer. For more
information, or to order a Keltron printer, contact Keltron Corporation at
the following address:
Keltron Corporation
225 Crescent Street
Waltham, MA 02154
617-894-8700
Figure 7: CRT-1 Connections
Keltron Printer
Option
CRT-1
Configuration
T
B
4
T
B
5
T
B
6
Connect CRT-1 pin 3 to TB4 TX
Connect CRT-1 pin 7 to TB4 REF
Connect CRT-1 pin 2 to TB4 RX
Plug this DB-25 connector
into the RS-232 port of the CRT-1.
CRT-1A
IFC-200
System Common (-)
IFC-200, TB1-2, or
Enclosure
CRT-1
7321
TX REF RX REF
OUT OUT IN IN
A B B+- A+- B- A-

Hardware Installation—IFC-200 Hardware Installation Procedures 13
1. Enter Setup Mode on the CRT-1 by pressing
SHIFT
and
Setup
Hold
simultaneously.
2. Notice that the SET 0 setup menu displays on the bottom line of the
CRT-1 screen. In setup mode, there are six setup menus
(numbered 0-5). Each setup menu is divided into parameter blocks
containing user-selectable values.
3. Select the operational parameters for the CRT-1 as shown below.
CRT-1 (newer model with pastel-colored function keys only)
SET 0 | FDX | P PAGE | S PAGE | PROT OFF | COPY |
(MON) OFF | GRAPH OFF | HI OFF | RS:2400
SET 1 | KEYS: | REPT OFF | CLICK ON | EDIT DUPE |
MRG BL OFF | EOM: NULL | AUX 2400
SET 2| WRAP OFF | LF OFF | SCROLL ON | KB ON |
DISPLAY PE OFF | STD VID | X-ON ONLY
Note: KB OFF for a CRT-1 without a keyboard.
SET 3 | DATA BIT 7 | BIT8 0 | PARITY ON | PARITY
BIT EVEN | STOP BIT 1 | EMULATION T101+
SET 4 | CURSOR UL | CURSOR BLINK | HERE IS:~~|
TIME OFF | FREQ 60
Note: To change the “HERE IS” parameter, press the Enter key on
the number pad. Pressing Enter also saves changes.
SET 5| KB TYPE:US | STATUS LINE OFF | AUX/KB:KB |
AUTO PG OFF | AUX:X-ON ONLY | RS232
4. To advance through the blocks of a given setup menu, press
or
5. To advance through the setup lines, press
or
6. To change a parameter block press
SPACE
until the desired value is displayed, then press any arrow key to move
the cursor from the current parameter block.
7. To save Setup mode parameters entered, press
SHIFT
and
S
at
the same time. To terminate the Setup mode, press
Setup
Hold
.
8. All the values displayed in the parameter blocks on the screen are
stored permanently, even if power to the CRT-1 is removed.
Note: If any mistakes are made during the setup process, simply repeat
this procedure.

14 Hardware Installation—IFC-200 Hardware Installation Procedures
1. Enter Menu SET 1 Mode.
2. Position cursor to the field keys:
3. Program the function keys by entering the keys illustrated in Table 2
below.
Note: A first entry of 1 transmits keyboard data to the host only.
4. To save the function key programming, press
SHIFT
+
S
at the
same time.
Table 2: Function Key Programming
System
Function Function Key Clear Previous Data First Entry Second Entries Store Data
Acknow-
ledge
F12
Clear
1
SHIFT
+
~
`
SHIFT
+
L
Enter
Signal
Silence
F13
Clear
1
SHIFT
+
~
`
SHIFT
+
M
Enter
System
Reset
F14
Clear
1
SHIFT
+
~
`
SHIFT
+
N
Enter
Note: When programming function keys, use the Enter key located on the
number pad.
The IFC-200 communicates with intelligent and addressable initiating,
monitor, and control devices through a Signaling Line Circuit (SLC). The
SLC can be wired to meet the requirements for NFPA Style 4 (Figure 10),
Style 6 (Figure 11), or Style 7 (Figure 12). It is recommended that
twisted-shielded pair cable be used for the SLC as detailed in the Wire
Requirements section of this document.
M500XJ Isolator Modules permit a group of smoke detectors and modules
to be electrically isolated from the remainder of the SLC, allowing critical
SLC components to function in the event of a circuit fault (Figures 10, 11,
and 12). These are required to meet the requirements of NFPA Style 7.
Function Key
Programming
Wiring the
Signaling Line
Circuit
Isolator Modules

Hardware Installation—IFC-200 Hardware Installation Procedures 15
M500MJ and M501MJ addressable monitor modules allow the IFC-200 to
monitor entire circuits of conventional normally open contacts, alarm
initiating devices, manual pull stations, normally open alarm contacts of 4-
wire smoke detectors, heat detectors, waterflow, and supervisory devices
(Figures 18 and 19). The M502MJ Addressable Monitor Module can
directly power 24 VDC 2-wire UL Listed smoke detectors. Point
annunciation of manual pull stations is provided with the BGX-101L
addressable pull station (Figures 10 and 11).
Through M510CJ addressable control modules, the IFC-200 can
selectively activate indicating appliance circuits or Form-C output relays
(Figures 22 through 25).
Through the SLC, the IFC-200 communicates with intelligent ionization,
photoelectric, and thermal detectors (Figure 27).
The capacity of each IFC-200 is up to 99 intelligent detectors, and an
additional combination of up to 99 addressable pull stations, control
modules, and monitor modules. In addition, the IFC-200 supports four
indicating appliance circuits.
Note: Refer to the Supply Calculations section of this document and the
installation drawings supplied with each device for rating and
specification information.
Table 3: Communications SLC Performance
Fault Condition
Single
Open on
Loop
Single
Ground
on Loop Shorted Loop
Loop
Shorted and
Opened
Loop
Shorted and
Grounded
Loop
Opened and
Grounded Communications Loss
Style 4 (Two Wire) SLC Operation (Meets NFPA 72 Style 4 Requirements)
Trouble1Alarm
Capability
Trouble2
Trouble Trouble Trouble Trouble Trouble
Style 6 (Four Wire) SLC Operation (Meets NFPA 72 Style 6 Requirements)
Alarm
Capability
Trouble
Alarm
Capability
Trouble
Trouble Trouble Trouble Alarm
Capability
Trouble
Trouble
Style 7 (Four Wire) SLC Operation3(Meets NFPA 72 Style 7 Requirements)
Alarm
Capability
Trouble
Alarm
Capability
Trouble
Alarm
Capability
Trouble
Trouble Alarm
Capability
Trouble
Alarm
Capability
Trouble
Trouble
Notes: 1 Trouble indicates a trouble signal will be generated at the control panel during the abnormal condition.
2 Alarm Capability indicates an alarm signal can be transmitted to the control panel during the abnormal condition.
3 Loop operation meeting Style 7 requirements isolates entire physical “zones” on the communications loop from
faults that occur within other areas of the loop.
Monitor Modules
Control Modules
Intelligent
Detectors
Device Capacity

16 Hardware Installation—IFC-200 Hardware Installation Procedures
Style 4
Complete the following steps to determine branch resistance on a Style 4
SLC.
1. Short the termination point of one branch at a time and measure DC
resistance from the beginning of the SLC to the end of that particular
branch as shown in Figure 8. The total DC resistance from panel to
branch end cannot exceed 40 ohms.
2. Repeat this procedure for all remaining branches.
Add the lengths of all the branches on the SLC. This sum cannot exceed
10,000 feet (12 AWG).
Figure 8: IFC-200 Wire Requirements: Two-Wire, Style 4 SLC
SLC Resistance
Measurement
SLC Out
Branch
IFC-200
TB6 A
B B+ A+ B- A-
Branch B
Branch A
Branch C
Branch D
Branch E
SLC Out

Hardware Installation—IFC-200 Hardware Installation Procedures 17
Style 6
Total length of the SLC loop pair cannot exceed 10,000 feet (12 AWG).
DC resistance of the loop pair cannot exceed 40 ohms. Measure the loop
pair by completing the following steps:
1. Disconnect Loop Out and Return at the control panel.
2. Short the two leads of Loop Return.
3. Meter Loop Out as shown in Figure 9.
Figure 9: IFC-200 Wire Requirements: Four-Wire, Style 6 Circuit
IFC-200
Loop Out
TB6 A
B B+ A+ B- A-
Loop Return
No T-Tapping
Allowed
B=Output Loop
A=Return Loop

18 Hardware Installation—IFC-200 Hardware Installation Procedures
M510CJ
IFC-200
TB4
TB5
TB6
TX
REF
RX
REF
OUT OUT
IN IN
A B B+ A+ B- A-
For use with 1551J, 2551J,
and 5551J Intelligent Detectors
B501BJ Base
1
2
3
4
9
8
7
6
5
ION
PHOTO
THERM
Loop Address Type
2(+)
3
1(-)
M500MJ
1
2
3
4
9
8
7
6
5
M500XJ
1
2
3
4
9
8
7
6
5
1
2
3
4
9
8
7
6
5
M500XJ
Note:
M500XJ devices not
reguired to meet NFPA Style 4.
BGX-101 L
Seperate T-Tap
to other Loop Devices
Connect SLC + to TB6 B+
Connect SLC - to TB6 B-
FIG2-6
Figure 10: Two-Wire, Style 4 SLC Communications Circuit
(Supervised and Power-Limited)

Hardware Installation—IFC-200 Hardware Installation Procedures 19
M510CJ
IFC-200
TB4 TB5 TB6
TX
REF
RX
REF
OUT OUT
IN IN
A B B+ A+ B- A-
For use with 1551J, 2551J,
and 5551J Intelligent Detectors
B501BJ Base
1
2
3
4
9
8
7
6
5
ION
PHOTO
THERM
Loop Address Type
2(+)
3
1(-)
M500MJ
1
2
3
4
9
8
7
6
5
M500XJ
1
2
3
4
9
8
7
6
5
1
2
3
4
9
8
7
6
5
M500XJ
Note:
M500XJ devices not
required to meet NFPA Style 6.
BGX-101 L
Connect SLC + OUT to TB6 B+ and SLC - OUT to TB6 B-
Connect SLC + OUT to TB6 A+ and SLC - OUT to TB6 A-
FIG2-7
Figure 11: Four-Wire, Style 6 SLC Communications Loop
(Supervised and Power-Limited)

20 Hardware Installation—IFC-200 Hardware Installation Procedures
T
B
6A B B+ A+ B- A-
M500XJ
Isolator Module M500XJ Isolator Module
M500XJ
Isolator Module
M500XJ
Isolator Module
Protected
Premises
Area "1"
Protected
Premises
Area "3"
Protected Premises Area "2"
4wcl_2
Connect SLC + OUT to TB6 B+ and SLC - OUT to TB6 B-
Connect SLC + OUT to TB6 A+ and SLC - OUT to TB6 A-
Optional Optional
Optional Optional
IFC-200
Figure 12: Four-Wire, Style 7 Communications Loop
By flanking a group (zone) of devices on the SLC with a pair of M500XJ
fault isolator modules, each area is protected from a short circuit fault on
another area. When a short circuit occurs in one area, the M500XJ on
either end of that section of the SLC will open the SLC, thus allowing the
other addressable devices on the SLC to continue to communicate. For
example, a fault on Area 2 will not affect Areas 1 and 3. The isolator
modules on either side of Area 2 will open the loop. Area 1 will still
operate from power on Loop Out, and Area 3 will operate from Loop
Return. Since the IFC-200 will no longer be able to communicate with
Area 2, a trouble signal(s) will be generated for those devices (Invalid
Reply error messages). The Style 7 circuit does not allow T-tapping or
branching, and the ratings and characteristics for this circuit are the same
as for a four-wire circuit meeting NFPA Style 6 requirements. It is
recommended that no more than 30 addressable devices be located
between any pair of isolator modules.
Isolator Module
Operation