DirectLOGIC DL405 User manual

1
Manual Revisions
If you contact us in reference to this manual, be sure to include the revision number.
Title: DL405 Interrupt Input Module
Manual Number: D4–INTR–M
Issue Date Effective Pages Description of Changes
Original 8/94 Cover/Copyright
Contents
Manual History
1 — 24
Original Issue
Rev. A 6/98 Entire Manual
Manual Revisions Downsize to spiral Rev. A

1
Table of Contents
Introduction 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overview of the module’s operation 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Module Features 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interrupt Signal Processing 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
When do you need an interrupt? 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How does an interrupt solve response problems? 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How does the CPU process the interrupts? 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Special Considerations in CPU processing 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Do I have to use an Interrupt Module? 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
What can I use in the Interrupt routines? 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
When can the Interrupts Occur? 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Using the Interrupt Input Module...4 Steps 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Physical layout of the D4–INT components 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Step 1: Setting the DIP Switches 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Switch 1: Enabling/Disabling Input Points 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Switch 2: Selecting Rising or Falling Edge Triggering 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Switch 2: Selecting the Response Delay Time 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Step 2: Installing the Module in the Base 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Module Restrictions 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CPU Compatibility 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installing the Module in the Base 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O Points Used 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O Assignments with a D4–430 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O Assignments with a D4–440 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Step 3: Connecting the Field Wiring 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wiring Guidelines 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical Field Wiring and Internal Module Wiring 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Solid State Field Device Wiring 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Check the Terminal Block 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Step 4: Writing the Control Program 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Task 1: Enable / Disable the Interrupts 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Task 2: Place Numbered Interrupt Subroutines after the END Statement 20. . . . . . . . . . . . . . . . . .
Task 3: Understand the Types of Instructions used in Interrupt Subroutines 21. . . . . . . . . . . . . . . .
Task 4: Enter the Conditions for a Return from the Subroutine 22. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Environmental Specifications 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Specifications 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

111
Introduction
The DL405 Interrupt Input module (D4–INT) is
an 8-point isolated interrupt input module for
use with the DL405 family of products. The
module consumes 16 X input points and must
be installed in Slot 0, next to the CPU. You can
use two Interrupt modules, installed in Slots 0
and 1, if you are using a D4–440 CPU. (More
on this later.)
The Interrupt module is intended for applications
that have one or more high-priority events which
require immediate attention. That is, these are
events that cannot wait until the CPU has
finished it’s normal program execution.
When this high priority event occurs, the
interrupt module sends an interrupt signal to the
CPU. Once the interrupt is received, the CPU
immediately suspends its routine scan cycle
and jumps to a subroutine that corresponds to
the particular interrupt input signal.
The following diagram shows a brief overview of this concept.
I
N
T
C
P
U
Main Program
Interrupt
Subroutine(s)
1. Field device (event) triggers
an interrupt signal from the
interrupt module to the CPU.
2. CPU recognizes the interrupt, stops the
normal program execution, and jumps to
subroutine.
END Statement 3. CPU finishes the subroutine
executionandreturnstothepoint
where it left in the normal
program execution.
This module has some great features that make interrupt processing easier.
SInterrupts are prioritized (lowest number takes priority)
SRising or Falling edge trigger
SSelectable response delay (allows you to easily ignore false signals)
SModule parameters are easily selected by setting dipswitches on the
back of the module
SNo complex programming, only simple ladder instructions are required
SIf you don’t use all 8 points as interrupts, you can use the non-interrupt
points as regular discrete inputs.
Overview of the
module’s operation
Module Features

2
Interrupt Signal Processing
In normal circumstances, the CPU reads the status of input points, solves the relay
logic program, and then updates all of the output points. This process is called the
scan and usually takes place in a matter of milliseconds. The following diagram
shows how this works.
Solve
Program
Read
Inputs
Write
Outputs
Scan
Critical Event
Input Module
Off/On Delay
Output Module
Off/On Delay
Normal Scan
Solve
Program
Output Turns
On
Solve
Program
Event occurs in the middle of the
program execution
Longer Overall
Response Time
As you can see from the diagram, there can be a delay between the actual
occurrenceoftheeventandtheCPUprocessingrequiredtorespondtotheevent.In
mostapplications,thescanhappensdozensoftimesinasecond,sothedelayisnot
critical.
However, in some applications you can have events that require an immediate
response. For example, your application may have a critical event that requires an
action to be initiated within 10 milliseconds of when the event occurs. Even with a
veryfastscantime,itmaytake10to30millisecondstocompletelyscantheprogram
before it can update any outputs. So, you can see that you need some method for
interrupting the normal scan to react to these critical events.
When do you need
an interrupt?

333
What is needed is a mechanism for interrupting the normal CPU scan cycle when
something needs to be done. The CPU can then take care of what has to be done,
and go back to its normal business. Here is the same diagram, but it has been
changedtoshowhowtheCPUreactsiftheCriticalFieldEventisbeingmonitoredby
an Interrupt Input Module. There are several things to notice.
SThere is very little Off/On delay (the Interrupt Module has selectable
response, or filtering).
SWhen an interrupt is received, two things happen.
1. The CPU
finishes executing the current program rung .
2. The CPU then suspends the normal program execution and jumps to
a subroutine that corresponds to the interrupt point that became active.
SBy using Immediate Instructions in the Subroutine, you can quickly read
input points and write output points.
SThe CPU resumes the normal program execution on the rung
following
the rung that was being processed when the interrupt occurred.
Interrupt
Module
Off/On Delay
Sol
Prog
ve
ram
Solve
Program
Return to
point in program where
interrupt occurred
Scan
Critical Event
Output Module
Off/On Delay
Shorter Overall Response Time
Normal Scan
Solve
Program
Use Immediate Output in the Interrupt
Subroutine to turn output on before the
end of the normal scan
Event occurs in the middle of the
program execution
Execute
Subroutine
Interrupt Module has
selectable filtering for
shorter response delays
Read
Inputs
Write
Outputs
How does an
interrupt solve
response
problems?

4
ItmayhelpyoutounderstandexactlyhowtheCPUworkstogetherwiththeInterrupt
module to process the interrupt signals.
Single Interrupt Signal: When the interrupt input module senses an input signal, it
has an extremely short delay before it signals an interrupt. This
Response Delay
(also called filtering) can be selected via a dipswitch setting and helps reduce the
possibility of false interrupt signals. (The Response Delay ranges are discussed in
more detail later in this manual.)
Once the delay period has passed, the module will latch an internal signal and send
aninterrupt requestto theCPU. OncetheCPU receivesthe request,theCPU stops
itsnormalscantojumpintotheinterruptroutine;andatthesametime,sendsareset
signal back to the module. The following diagram shows this operation.
Input signal (X0)
Latch output
CPU resets latch
<0.08ms
0.16ms
0.5ms
Latch
This sig al ig ored,
duratio is less tha
respo se delay selectio
OffĆtoĆO delay expires, sig al is ot false. Module latches
sig al for 0.5ms, se ds i terrupt request to the CPU.
Execute
i terrupt
subrouti e 0
I terrupt
Mai
Program
Internal CPU
processing Back to
Mai
Program
Multiple Signals from the Same Interrupt Input: There may be occasions where
several interrupt signals are received very close together in time. In the diagram
below, the time line reads from left to right. The first signal is latched. It takes 0.5
millisecondstocompletethelatchingprocess.Ifwithinthattimespananothersignal
is sent, the module will ignore the second signal and only recognize the first.
Execute
i terrupt
subrouti e 0
I terrupt
Mai
Program
Internal CPU
processing Back to Mai
Program
Input signal (X0)
Latch output
CPU resets latch
0.16ms
0.5ms
Latch
This sig al ig ored,
occurred while i terrupt
poi t was bei g latched.
0.16ms
Respo se delay
expires, latch sig al
How does the CPU
process the
interrupts?

555
Simultaneous Signals from Different Interrupt Inputs: What happens if the
module senses signals simultaneously from several of the interrupt input points? In
this case, there is a priority. The highest priority is given to X0, then comes X1, then
X2 and so forth down to X7. The diagram below shows two signals being received
simultaneously.
Execute
interrupt
subroutine 0
Input signal (X0)
Latch interrupt
request 0
Reset latch 0
Input signal (X1)
Reset latch 1
Interrupt
Main Program
Internal CPU
processing
Latch interrupt
request 1
Back to Main
Program
Execute
interrupt
subroutine 1
(Example assumes that signals are true, and does not show response delay)
In each of the previous examples, you noticed that the CPU interrupted the main
program execution. The CPU does not just drop everything that it is doing. Instead,
the CPU performs an orderly transition to the subroutine by
finishing the current
programrungbefore it jumpstothesubroutine.
Thistypicallytakes atleast 1ms,but
the actual response depends on the instructions on the rung. For example, if the
CPU receives the interrupt signal on a rung that contains several math instructions,
then the response will be slower than if the rung only contained a simple output coil.
There’s not much you can do about this, but just be aware of it.
Also, since the CPU only executes the logic in the interrupt subroutine, it does not
handle any communication requests from external devices. In the vast majority of
casesthisisnotaproblem.However,someoperatorinterfacescanhavea“timeout”
type of error if they issue a request and do not get a response from the CPU in a
certain amount of time. If you are using an Operator Interface and this happens, try
reducing the communications baud rate. The slower speeds usually allow for a
longer response time from the CPU.
Special
Considerations in
CPU processing

6
You don’t always have to use an Interrupt Input module to generate an interrupt.
Basically, an interrupt can be initiated two different ways:
SYou can use a timed interrupt (an interrupt on a defined time interval,
D4–440 CPU only)
SOr, you can use the Interrupt Input module (interrupt triggered by a limit
switch closing, proximity switch, etc. via the interrupt module)
NOTE: Theseexamples DO NOT show all oftheinstructionsnecessary to correctly
program an interrupt routine. This is discussed later in this manual.
Timed Interrupts: The D4–440 offers a
single timed interrupt
instruction . You can
specify how often the interrupt occurs,
from 3–1000 ms. This is great for those
applications where you know you need to
takesomeactioneverysooften.However,
itmayalsoslowthesystemdownbecause
it may be executing even when the
machine (or process) doesn’t need
immediate attention.
NOTE: The time value is specified in
BCD format. If the number is not BCD,
or if the number is outside of the range
(3–1000) then the routine will not work.
You may have noticed that we didn’t
mentionthe D4–430. Timed Interrupts are
not available in the D4–430.
INT O 17
END
Y5
OUTI
X20
LD K10
X1
Load the constant, K10,
which will indicate 10
milliseconds
OUT V737
Copy the value to V737, which
is used to define the time inter-
val for the timed interrupt
Interrupt happens
every 10ms in
this example
Hardware Interrupts: In the vast majority of
applications, there is some real world event,
such as a switch closing, etc. that needs to
trigger an interrupt. By wiring these field
devices to an Interrupt Input module, you
can easily interrupt the CPU scan cycle
when the event occurs. INT O 1
END
Y5
OUTI
X20
INT O 2
Y6
OUTI
X21
Whenthe interrupt inputpointcomes on,
the CPU suspends the normal program
execution and jumps to the interrupt
routine that corresponds to the interrupt
point, X0 – Interrupt 0, X1 – Interrupt 1,
etc. Once the subroutine execution is
complete, the CPU returns to the main
program.
In the example shown here, the CPU
automatically handles the transition to
the Interrupt subroutine whenever
Interrupt input X1 comes on.
(Main program)
Executes routine
and returns to the
main program
IRT
Do I have to use an
Interrupt Module?

777
X20
In any of the above methods, Interrupt
subroutines are required. These subroutines
are placed
after the END statement, which is
the last line in the main program.
INT O 1
END
Y5
OUTI
X21
INT O 2
Y20
OUTI
X40
(Main Program)
You can use most any type of instruction
in the subroutines. You can have math
instructions, data manipulation
instructions, etc. However, most people
find that the Immediate instructions and
the FOR/NEXT looping instructions are
the most useful. Immediate instructions
immediately read the status of inputs
and/or immediately update the outputs.
Byusingtheimmediateinstructionsinthe
subroutine, the CPU can read input
points or update output points
immediately. By using the FOR/NEXT
instructions, you can literally have a
“mini-scan” by creating a loop inside of
the subroutine.
K3
FOR
Y6
OUTI
X22
NEXT
Y7
OUTI
X23
123
(Loops 3 times before
returning to program)
IRT
NOTE:Youcanuse manydifferenttypesof instructionsinthe interruptsubroutines.
However, if you use instructions with long execution times, such as some math
instructions,FOR/NEXTloops,etc.,thenyoumayexceedtheWatchdogTimerlimit.
The Watchdog Timer is set at 200ms from the factory. It can be changed with the
handheldprogrammeror
Direct SOFT.YoucanalsouseaRSTWTinstructioninside
of the subroutine to reset the Watchdog Timer.
ThepreviousdiagramsshowedasimplifiedCPUscancycle.However,theCPUcan
process the interrupts during any portion of the scan cycle. Interrupts can occur in
themiddleofthecommunicationsservice,inputupdate,outputupdate,etc.So,this
helps ensure the fastest possible response for critical events.
The CPU does not perform any other functions when it is executing the interrupt
subroutine. For example, the CPU will not acknowledge any communication
requestsuntilithasfinishedwiththeinterruptsubroutine.Somedevices,suchasan
operatorinterface,mayissueacommunicationstimeouterrorduetothe delayinthe
response from the CPU. If this occurs, check your device documentation for
procedures on changing the communications timeout error settings.
Now that you understand how the CPU processes the Interrupts, you’re ready to
install (and use) the D4–INT Interrupt module.
What can I use in
the Interrupt
routines?
When can the
Interrupts Occur?

8
Using the Interrupt Input Module..4 easy steps!
Yes, I know, you were expecting to see the “4 Steps” on this page. But, first, take a
minute and familiarize yourself with the basic physical characteristics. It will make
the “4 Steps” even easier.
SThe dipswitches are located on the back of the module.
SThe terminal block can be easily removed by loosening the terminal
block retaining screws.
SThe LED status indicators show you when an input is active.
Base Connector
DIP Switches for response
time, trigger direction &
enable/disable
Status Indicators
Removable
Terminal Block
TB
INTERRUPT MDOULE
0
1
2
3
4
5
6
7
Front Back
D4-INT
Physical layout of
the D4–INT
components

999
Now that you know your options in using Interrupt processing, it’s time to learn the
basic setup requirements for the Interrupt Module.
Switches
Install
Step 1:
Set the DIP Switches.
Terminal screws
Step 2:
Install the Module in the Base.
Step 3:
Connect the Field Wiring.
Step 4:
Write the Control Program with
simple RLL Instructions.
INT O 1
END
Y5
OUTI
X20
(Main Program)
IRT

10
Step 1: Setting the DIP Switches
There are two banks of DIP switches, SW1 and SW2, located on the back of the
module. You can enable/disable interrupt points; adjust the response time, and set
the triggering to be either on the rising edge or trailing edge of the input signal. The
following table shows an overview of the switch settings. If you are unsure of the
meaning of some of these options, just keep reading. The remaining paragraphs
explain these in more detail.
SW1 Position 1 2 3 4 5 6 7 8
Input 0 1 2 3 4 5 6 7
SW1
ON
SW2
ON
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
ON = ENABLE OFF = DISABLE
SW2 Position
Input 0, 1 2, 3 4, 5 6, 7
1 2 3 4
ON=Interrupt triggered by the rising edge
OFF= Interrupt triggered by the falling edge
SW2 Position
Input
5 6 7 8
0 1 2 3
ON=Low speed (slower response time)
OFF= High speed (faster response time)
By setting the switches1 thru 4 of
SW2, you can select whether the
interrupt is triggered on the rising or
falling edge.
By setting switches 5 thru 8 of SW2,
you can select the response delay
time from one of two ranges for
inputs 0 thru 3. This feature is not
available for inputs 4 thru 7, which
are always set at the fastest
response time.
By setting the switches1
thru 8 of SW1 to the ON
or OFF position, you can
ENABLE or DISABLE the
corresponding inputs as
indicated.
Positions 1–8 on Switch 1 enable (or disable) each individual interrupt point. Your
applicationmaynotrequirethatall8inputsbeusedasinterruptinputs.Forexample,
you may only need one interrupt input. In this case, you could use the other 7 points
as normal discrete inputs.
You can enabletheinterrupt for eachindividualpoint by slidingtheDIP switch tothe
positionONforthoseinputpointsyouwishtoenable.Forexample,slidingposition4
to the ON position will enable input point X3.
NOTE: Any points not designated as interrupt points can be used as normal input
points
. For normal inputs, set the switch to the OFF position.
Switch 1:
Enabling/Disabling
Input Points

11 1111
Positions1,2,3and4 onSwitch2determinewhethertheinterrupt istriggeredonthe
rising (leading) edge of the input signal or on the falling (trailing) edge of the input
signal. This is often called “triggering.” The examples earlier in this manual showed
the timing diagrams with a Rising edge trigger. They could just as easily have been
shown using the falling edge trigger. The following diagram shows the difference.
Rising edge
Module starts the latching
process when the input comes ON
Input OFF
Falling edge
Module starts the latching
process when the input goes OFF
Input ON
Set the dipswitches to the ON position for rising edge triggering, or set the
dipswitchesto OFF forfalling edge triggering.You will alsonotice that thepointsare
“paired.” That is, one switch sets the triggering for
two points. For example, If you
slide the position 2 switch to the ON position, then
both inputs 2 and 3 will generate
interrupts on the
rising edge.
Switch 2:
Selecting Rising or
Falling Edge
Triggering

12
Positions 5,6,7 and 8 on Switch 2 control the response delay time for the first four
input points only (X0 – X3). The response delay is defined as follows:
SOff-to-On Delay — the amount of time between the occurrence of the
field event, such as a switch closing, and the Interrupt module point
turning on.
SOn-to-Off Delay — the amount of time after the field event is complete,
such as a switch opening, and the Interrupt module point turning OFF.
Field Event
Field event occurs. This could be
a switch closing.
OFF to ON
delay
ON to OFF
delay
There are two speeds for response.
SSlow Response — 0.88ms–6.47ms for off–to–on delay and
1.64ms–9.81ms for on–to–off delay.
SFast Response — 0.08ms to .59ms for off–to–on delay and
0.15ms–0.89ms for on–to–off delay.
Youwillnoticearangeoftimeshown.Thismeansthattherecanbeavarianceinthe
responsetimes, so we recommend that you planyourapplication for the worst case
scenario.
Selectingaslowerresponsetimecanbehelpfulifyourcriticalfieldeventinputsignal
is electrically noisy, or, if you expect contact bounce on the switch. (The slower
response provides more filtering and helps reduce the possibility of false input
signals. If you have input signals that are subject to these possibilities, it is best to
connect them to the first four inputs on the module.)
NOTE:Thisfeatureisavailableforthefirstfourinputs(X0,X1,X2,andX3)only.The
response time for inputs X4, X5, X6 and X7 is not configurable. The off–to–on delay
and the on–to–off delay for these are fixed at the fast response delay time.
Switch 2:
Selecting the
Response Delay
Time

13 1313
TheResponseDelayhelpsyouunderstandhowlongitwilltaketheInterruptmodule
to latch the interrupt signal. The following diagram shows how the Off-to-On delay
affects a signal with Rising edge triggering.
Input signal
Fast Response
(start of latch)
Response Delay Range for Rising Edge Triggering
Slow Response
(start of latch)
Rising edge
0.08 - 0.59ms
0.88 - 6.47ms
0.5ms latch
0.5ms latch
For falling edge triggered signals, the On-to-Off delay is more important. This is
because the Interrupt module “waits” for a normally high signal to go low before it
recognizesaninterrupt.So inthiscase,theOn-to-Offdelayfiltersoutany bounceor
false signals.
Input signal
Fast Response
(start of latch)
Response Delay Range for Falling Edge Triggering
Slow Response
(start of latch)
Falling edge
0.15 - 0.89ms
1.64 - 9.81ms
0.5ms latch
0.5ms latch

14
Step 2: Installing the Module in the Base
WARNING: To minimize the risk of electrical shock, personal injury, or
equipment damage, always disconnect the system power before installing or
removing any system component.
There are a few restrictions that you need to consider if you are using this module.
SThe module must be installed in slot 0, which is adjacent to the CPU.
SThe module
cannot be installed in an expansion or remote base. That is,
it must be installed in the CPU base.
SIf you’re using a D4–440 CPU, you can have two interrupt modules.
They must be placed in slots 0 and 1.
SIf you’re using a D4–440 CPU and a Timed Interrupt subroutine
(INTO17) then you
cannot use the 8th interrupt point on the second
interrupt module. (The CPU always uses INTO17 as the Timed Interrupt
subroutine. If you’re using the timed interrupt, disable the hardware
interrupt point by using the dipswitch on the rear of the module.)
If you have purchased your CPU unit from PLC
Direct , your firmware will
automatically support the interrupt input module. This module may also work with
405 CPUs provided by previous vendors. However, if you have an older 405 CPU
with firmware prior to version 1.6, you will have to upgrade your firmware. Contact
PLC Direct for more information.
With the power disconnected, you are now
ready to install the module in the base. Here
are four steps for making the installation:
1. Notice the module has a plastic tab at the
bottom and a screw at the top.
2. With the module tilted slightly forward,
hook the plastic tab on the module into the
notch on the base.
3. Next, gently push the top of the module
backtowardthebaseuntilitisfirmlyseated
into the base.
4. Now tighten the screw at the top of the
module to secure the module to the base.
CPU
Unit
Interrupt
Input
Each Interrupt module consumes 16 input points. The first group of 8 points can be
used as the interrupt points. The second group of 8 points are used internally by the
interrupt module. If you do not use all of the first 8 points as interrupts, then you can
use them as normal discrete inputs. You cannot use the next 8 points for other
purposes. They are always reserved for the Interrupt module internal operation.
Module
Restrictions
CPU Compatibility
Installing the
Module in the Base
I/O Points Used

15 1515
You can only use one Interrupt module with the D4–430 CPU. Since the module
mustbeplacedin slot0,thepointsusedareX0 –X17.Thefollowingdiagramshows
an example system with I/O assignments.
16pt
Input








D4–INT


X0
–
X7
X20
–
X27
X30
–
X67
X70
–
X77
Interrupt Input module must
be placed in Slot 0, next to the CPU Interrupt inputs appear on
I/O points X0 – X7
012345
X10
–
X17
Slot
EachInterruptmoduleconsumes16inputpoints.YoucanusetwoInterruptmodules
with the D4–440 CPU. Since the modules must be placed in slot 0 and slot 1, the
points used are X0 – X17 for the first module, and X20–X37 for the second interrupt
module. If you only use one interrupt module, install it in slot 0. (You can install
another type of module in slot 1.) The following diagram shows an example system
with I/O assignments for a D4–440 with two Interrupt modules.
D4–INT
Interrupt Input modules must be placed
in Slot 0 and Slot 1, next to the CPU Interrupt inputs appear on I/O
points X0 – X7 for the first module;
X20 – X27 for the second module
012345
D4–INT
16pt
Input
16pt
Input








X0
–
X7
X20
–
X27
X40
–
X77
X100
–
X107
X10
–
X17
Slot
X30
–
X37
NOTE: The D4–440 supports manual I/O configuration. That is, you can manually
assign the I/O addresses in any order. If you use manual configuration, make sure
you
must install the Interrupt modules (and use the addressing) as shown above.
Now that you understand the module placement and the I/O assignments, you’re
ready to connect the field wiring.
I/O Assignments
with a D4–430
I/O Assignments
with a D4–440

16
Step 3: Connecting the Field Wiring
WARNING: To minimize the risk of personal injury or property damage,
remove all power from the PLC and field devices before wiring the module.
The D4–INT Interrupt Input Module features a
removable terminal block. It is held into place
by two retaining screws. You must first remove
the front cover of the module prior to wiring. To
remove the cover press the bottom tab of the
coverand tilt the cover up to remove it from the
module. Now loosen the retaining screws and
lift the terminal block away from the module.
Terminal screws
Retaining screw
Consider the following wiring guidelines.
1. Thereisalimittothesizeofwirethemodulescanaccept. Thetableliststhe
maximumAWGforeachmoduletype(smallerwireisalsoacceptable).The
interrupt module follows the 16 point guidelines.




8 point 12
16-point 14
32-point (common) 20
32-point (other) 24
NOTE: 12 AWG Type TFFN or Type MTW can be used on 8pt. modules. 14 AWG
TypeTFFNorTypeMTWcanbeusedon16pt.modules.Othertypesofwiremaybe
acceptable, but it really depends on the thickness of the wire insulation. If the
insulation is too thick and you use all the I/O points, then the plastic terminal cover
may not close properly.
2. Always use a continuous length of wire, do not combine wires to attain a
needed length.
3. Use the shortest possible cable length.
4. Where possible, use wire trays for routing.
5. Avoid running wires near high energy wiring.
6. If possible, avoid running input wiring in close proximity to output wiring.
7. To minimize voltage drops when wires must run a long distance, consider
using multiple wires for the return line.
8. Where possible, avoid running DC wiring in close proximity to AC wiring.
9. Avoid creating sharp bends in the wires.
Wiring Guidelines

17 1717
Shown below is a wiring diagram with typical field wiring and details relating to the
D4–INT module’s internal wiring. There are a few things you need to know before
you connect the field wiring.
SEach channel is isolated, so you can use sinking or sourcing
configurations independently for each point.
SUnused inputs do not require any connections.
0
1
2
3
4
5
6
7
TB
INTERRUPT MODULE
D4–INT
Optical
Isolator
Derating Chart for D4–INT
0
2
4
6
8
Points
Common
Input
C0
0
C0
0
C1
1
C2
2
C3
3
C4
4
C5
5
C6
6
C7
7
– +
10.2–26.4VDC
4–18mA
C1
1
C2
2
C3
3
C4
4
C5
5
C6
6
C7
7
– +
– +
+ –
+
–

Ambient Temperature (°C/°F)
      °°
To
To
L
Current sourcing configuration shown
Module
sources current if
supply is connected as
shown here.
Module
sinks
current if
supply is
connected as
shown here.
These points show you how to
connect the interrupts with a single
supply.
This method can only be
used if no channel-to-channel
isolation is required
.
+ –
+ –
Circuitry
+V Response
Time Switch*
* Response delay switch is set with Switch 2,
positions 5–8 on rear of the module. This is only
for points X0 – X3. Points X4 – X7 are fixed at the
fastest response.
Typical Field
Wiring and Internal
Module Wiring

18
Thefollowing diagrams show how to connect solidstatefield devices to the D4–INT
Interrupt Input module.
* Response delay switch is set with Switch 2,
positions 5–8 on rear of the module. This is only
for points X0 – X3. Points X4 – X7 are fixed at the
fastest response.
Sensor
+
Output
– +
12 – 24VDC
C0
0
(NPN) Current Sinking
Field Device
-
NPN Field Device Example
Optical
Isolator
To
Circuitry
+V Response
Time Switch*
D4–INT
* Response delay switch is set with Switch 2,
positions 5–8 on rear of the module. This is only
for points X0 – X3. Points X4 – X7 are fixed at the
fastest response.
Sensor
+
Output
+ –
12 – 24VDC
(PNP) Current Sourcing
Field Device
-
PNP Field Device Example
C0
0Optical
Isolator
To
Circuitry
+V Response
Time Switch*
D4–INT
After you have finished making the wiring
connections, install the terminal block on the
module, making sure the terminal block is
tightly seated. Be sure to tighten the retaining
screws.Alsoverifythatthelooseterminalblock
LED is off when the system power is applied. If
the TB LED is on, then the terminal block is not
connected properly.
TB
INTERRUPT MODULE
0
1
2
3
4
5
6
7
D4-INT
Onceyouhavethe fieldwiring connected,you’re readyto writethecontrolprogram.
Solid State Field
Device Wiring
Check the Terminal
Block