ICS Regent+Plus
®
PD-7032
Fire Detector Input Modules
(T7419)
Issue 1,
Fire detector input modules provide interfaces for 16 fire
detector inputs such as smoke detectors, flame detectors,
temperature detectors, and manual alarm call points. Eac
module performs line monitoring on the field wiring
connections and automatic testing of the module’s input
electronics. Input and line status are reported back to the
controller for use in application program logic.
March, 06
h
Features
·
Sixteen input points.
·
Individual channel Reset control output to reset latched fire
detectors.
·
Fault tolerant operation when redundant modules and sensors
are configured.
·
Hot-replaceable.
•
Complete, automatic testing of all input circuits.
•
Automatic line monitoring detects open and short field wiring
faults.
·
Individual front panel indicators on each module show the
module’s fault/active and power status, as well as input status
indicators for each point.
·
2500 volt minimum electrical isolation between field and logic
circuits.
·
TÜV certified, Risk Class 5.
The input module circuits are thoroughly tested, providing a
fail-safe interface for safety critical inputs. For fault tolerant
configurations, two fire detector input modules are used to
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1
Fire Detector Input Modules
connect to redundant field sensors. In this dual module
configuration, a failed module can be removed and replaced
without affecting system operation.
The module requires connection to a field power supply
voltage, ranging from 15 to 40 VDC. This supply voltage is
internally regulated to power the fire detector field input
circuits.
(T7419)
Module Operation
A block diagram of a typical fire detector input module is
shown in Figure 1.
2
Figure 1. Block Diagram of Fire Detector Input Module.
A field power supply is connected to the fire detector input
module. The field power is internally regulated to 23.5 Vdc to
power the fire detector field inputs. Each input is b
Industrial Control Services
iased to
Fire Detector Input Modules
(T7419)
this regulated voltage with an internal resistor. Externally
each input connects to an associated field sensor and a line
terminator. The module monitors the input voltage to detect
a variety of input states. The module can discriminate and
report sensor tripped, sensor healthy, line open and line
shorted conditions. Additional circuits allow the module to
reset a latched fire detector by removing power from the
associated input circuit.
Internally the module generates a reference voltage that
is
compared to the field inputs. The comparator generates an on
or off state depending on which voltage is greater. The field
side FPGA controls and monitors the reference voltage signal
and reads the status of all 16 input comparators. This
information is stored and sent through optical isolation to the
logic-side FPGA. This FPGA interfaces the input date to the
I/O safetybus and drives the module’s front panel indicators.
Testing and Diagnostics
Standard I/O Module Testing
The processor modules send triplicated read data requests to
the input module over the I/O Safetybus. The processors’
addressing data and data read requests are voted by the
module (preventing I/O Safetybus failures upstream from the
module from affecting its ability to be read). The voted result
is then passed to the I/O bus interface logic.
After receiving the voted data read request, the I/O bus
interface logic sends its input data to the module’s three bus
drivers. Each of the three bus drivers is independently
controlled —
propagated into the rest of the system.
pre
venting failures in a single driver from being
PD-7032
Mar-06
The bus drivers then move the data onto the I/O Safetybus
which, in turn, passes it to the processors.
Each module’s voter circuits are periodically tested by the
processor modules. Discrepant data are sent through one of
three legs of the I/O Safetybus to determine whether the
module’s voter is able to outvote the incorrect data. A failure
to return the correct majority-voted result to the processors
produces an I/O mo
modules and a module fault indication at the I/O module.
3
dule error indication at the processor
Fire Detector Input Modules
Each type of module has a unique identification code that is
read by the controller. This code lets the controller know
which type of module is installed in each I/O chassis slot and
address that module and its points specifically. The processor
modules periodically check each module’s identification code
to determine whether the type of module installed matches
type of module indicated in the I/O configuration
loaded when the system was started. If a module is removed,
or is replaced with a module of a different type, the processor
modules will indicate I/O module errors.
Loopback logic tests periodically write data to the module and
then read it back to determine whether the module’s I/O bus
interface logic is functioning correctly.
(T7419)
that was
Input Circuit Testing
The field interface circuits of the fire detector input module
are completely tested to detect stuck-on or stuck-off input
circuit faults and identify input wiring open and short circuits.
The automatic execution and evaluation of the input testing
is controlled by the triplicated Regent processor modules.
During normal operations, the internal reference voltage is
set to three levels and the comparator output is read. These
three reference voltage levels represent thresholds that
determine whether the input signal is in alarm or healthy and
if the field wiring is open circuit or short circuit. The logic-side
FPGA determines input status and line fau
lt status based on
the comparator data for the three voltage levels. The FPGA
data is provided to the I/O processors for application
processing.
On a background basis, the I/O processors test the input
circuit comparators and logic circuits for stuck-on and stuck
off failure modes. During testing the D/A converter generates
two reference voltages outside the normal operating range of
the field input voltages to test that the comparator output can
turn-off and turn-on. The I/O processors read the resultin
g
input status, line fault status, and reference voltage readings
for the test cycle to determine if there are faults in the input
circuits or the common data paths.
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Industrial Control Services
Fire Detector Input Modules
Note:
(T7419)
If the I/O processors detect a faulted input circuit, an I/O
module fault is indicated at the processor modules and the
Fault LED on the face of the input module is turned on.
Input Circuit Test Interval
The Regent processor modules schedule testing of the input
circuits on a background basis. The test interval for these
circuits may range fro
m a few seconds to several minutes,
depending on the application program scan time and the size
of the I/O configuration. The equation below can be used to
estimate the test interval for monitored digital inputs.
TI = 172 * IOU
where:
TI
IOU
TSCAN
=
=
QTY
=
* TSCAN + 2
QTY
Test interval, seconds
Quantity of I/O Units in the system (1 to 16)
The application program scan time, seconds
For example, for a system with 8 I/O units and an application
scan time of 60 milliseconds, the test interval would be:
TI = 17
2 * IOU
TI = 84.6 seconds
* TSCAN + 2 = 172 * 8 * 0.060 + 2
QTY
In this system, all of the fire detector input modules would be
tested for stuck-on and stuck-off faults approximately every 85
seconds. This test interval can be used in reliability and
availability calculations to select the fault tolerant input
configuration that meet the application’s safety requirements.
PD-7032
Mar-06
Due to I/O processor fault filtering algorithms, it may take up
to four test intervals to report a failed input module as
permanent fault
Front Panel Indicators
a
Figure 2 shows the physical features of the fire detector input
modules. The front panel of each module contains fault/active
and power indicators for the module as well as input status
indicators for each channel.
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Fire Detector Input Modules
(T7419)
6
Figure 2. Fire Detector Input Module.
Industrial Control Services
Fire Detector Input Modules
(T7419)
Active/Fault Status Indicator
This green and red LED pair indicates the overall health of
the module and its field circuits. During normal operatio
green ACTIVE indicator flashes at the controller's scan rate.
If a module fault occurs the red FAULT indicator switches on
and the green indicator switches off.
Power Status Indicator
The POWER OK LED indicates the presence of field voltage
at the module’s field power input terminals and the overall
health of the module’s field power regulator circuits.
Input Status Indicators
Input status indicators show Fault and Alarm status for each
point.
A red ALARM status indicator turns on when the fire detec
input is in the tripped alarm state. The indicator is also on if
the input signal is shorted.
A yellow FAULT indicator turns on when the input circuit is
open or short circuit.
n the
tor
Application
Simplex Configuration
Fire detector input modules provide a suitable interface to
safety-critical input signals.
Fire detector input modules provide a suitable interface to
safety-critical input signals. The circuits in the input modules
are automatically tested and annunciated, providing a fail
safe interface to digital inputs.
Fault Tolerant Connection
For critical inputs, redundant input modules are used with
redundant input sensors in a fault tolerant configuration. In
this configuration each input module is connected to one of
two redundant sensors in the field. With this configuration, if
a fault occurs on one module or sensor, it can be removed and
-
PD-7032
Mar-06
7
Note:
Fire Detector Input Modules
replaced while the system continues to sense the inputs from
the remaining module.
In certain applications it may be possible to connect single fire
detector
this option, consult the factory for details.
(T7419)
s to redundant input modules. For consideration of
Field Wiring
For field wiring details, refer to PD-7901 - I/O Termination
Assembly (ITA).
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Industrial Control Services
Fire Detector Input Modules
(T7419)
Matching the Input Thresholds to Specific Field Devices
The Fire Detector input module has a input characteristic
load-line that is illustrated in Figure 3.
PD-7032
Figure 3. Input Characteristics of the Fire Detector Input
This figure plots the input voltage versus loop current. Along
the curve, several points are plotted which indicate the loop
resistance that produces the load-line characteristics. When
Mar-06
9
Note:
Fire Detector Input Modules
applying the module to specific fire detectors, the operating
points for Fire Detector -Normal, Fire Detector - Alarm, Open
Circuit and Short Circuit should be examined. Each of these
points should fall within the boundaries determined by the
input module thresholds. If necessary the thresholds can be
adjusted during configuration of the module using
W
INTERPRET
For example, consider a fire detector that has an alarm
characteristic of 300Ohm with a 4Vdc Zener and a line
termination resistor of 3K Ohms. When the fire detector is in
the normal state (not tripped) the input load is only the 3K
Ohm termination resistor. This is illustrated in Figure 3 as
line A. The point at which this line intersects the load-line
represents the input voltage and loop current when the fire
detector is in the normal state. This point is located we
between the default Open Circuit current threshold (3 mA)
and the default On/Off Alarm threshold (10.5 mA).
(T7419)
.
ll
Next, the fire detector alarm state should be examined. The
alarm resistance of the fire detector is 300 Ohms and this is
illustrated as Line B in the figure. However, the 4 Volt Zener
of the fire detector offsets the operating point by 4 Volts as
shown by Line C. The point at which Line C intersects the
load-line represents the input voltage and load current when
the fire detector is in the ala
rm state. This point should be
between the On/Off threshold and the Short Circuit threshold.
In this case the alarm point is rather close to the Short Circuit
threshold so it may be necessary to modify the Short Circuit
threshold to a slightly higher value, like 17 mA.
Finally, the Open Circuit and Short Circuit conditions must
be examined. In this example, the Short Circuit condition is 0
Ohms (or a small amount of resistance representing the field
wire resistance to the point at which the short occurs)
. This
would place the Open Circuit point near to the point where the
load line intersects the x-axis in the Figure. Similarly, the
Open Circuit is infinite Ohms which would place the operating
point where the load-line intersects the y-axis.
10
In many applications you may also connect and intrinsic
safety barrier in the field loop. In these applications the
resistance and voltage drops of the barrier must also be
included in determining the operating points of the input
Industrial Control Services
Fire Detector Input Modules
(T7419)
circuit under all four operating conditions. If necessary,
contact the factory for assistance in applying your specific
field inputs and barriers to the fire detector input module.
Keying
The I/O chassis can be physically keyed to prevent accidental
damage caused by inserting a module into a slot wired for a
different module type. Figure 4 illustrates how the slot keys
are installed on the I/O chassis slot field wiring connectors.
The slot key positions for the monitored digital input module
are listed in Ta
ble 1.
PD-7032
Mar-06
11
Module
Upper
Connector
Lower
Connector
T7419
11
7
Fire Detector Input Modules
(T7419)
Figure 4. Installing Slot Keys.
Table 1. Slot Key Positions.
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Fire Detector Input Modules
(T7419)
Configuration
Each fire detector input module is configured using the
W
INTERPRET I/O Configuration Editor. In the editor, you will
perform the steps described below to configure the input
module.
1) Set the Module Type:
Position the cursor on the module slot you wish to define.
Choose Set Module Type from the Edit Menu and select
the T7419, Fire Detector Input Module from the list.
2) Edit the Module Definition:
Choose Edit Module Definition from the Edit Menu. A
dialog box will open where you can define the input module
and point definitions.
PD-7032
Mar-06
Figure 5. Fire Detector Input Module Definition.
3) Define the Input Module Fields and Thresholds:
With the cursor at the top of the list in the Module
Definition dialog shown in Figure 5, open the Fire Detector
I
nput Module dialog by pressing Enter or double clicking
on the “(Module)” selection. The dialog box shown in
Figure 6 will open.
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Fire Detector Input Modules
(T7419)
Figure 6. Defining the Input Module Fields and Thresholds.
In the module definition dialog you can define a tag names
representing all sixteen input points as a 16-bit word. For
example, the Name field represents the On/Off status of all
sixteen inputs
The module tag names represents the 16 inputs as a
signed, 16-bit integer. In th
is format, input point one is
the least significant bit (LSB) and input point 16 is the
most significant bit (MSB). Enter tag names up to 12
characters long and descriptions up to 40 characters long.
In the module definition dialog you can also set the
threshold currents used to determine the Open Circuit,
On/Off, and Short Circuit input status. These values may
need to be changed to suit the characteristics of the fire
detector inputs that you are using. Refer to page 9 for
discussi
Detectors.
on on Matching Input Thresholds to Specific Fire
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Industrial Control Services
Fire Detector Input Modules
(T7419)
3) Edit each point:
Choose Edit from the Module Definition dialog box to
define a name and description for each input point. In the
Fire Detector Input Point dialog, enter names and values
for the configuration fields as described below.
PD-7032
Mar-06
Figure 7. Defining a Fire Detector Input Point.
Name
Also called the tag name, this is the name used in the
application program to reference the fire detector input’s
Tripped/Healthy state. The name can be up to 12 characters
long.
Description
This 40-character field provides a place to describe the input
point definition. The description is used to help document
your system (it does not affect application program operation).
Fault Name
This is the name used in the application program to reference
the input point line fault status. The name can be up to 12
characters long.
15
Note:
Fire Detector Input Modules
During operations the input circuit is monitored for open
circuit and short circuit wiring faults. This bit is normally on
a
nd turns off if either an open circuit or short circuit is
detected.
Line fault status is only reported through the Fault Name
variables. Line faults are not reported as a permanent I/O
module fault and do not turn on the associated system control
relay fault bit for the module. Line faults are not latched. If a
line fault condition returns to normal, the Fault Name
variable status also returns to normal.
(T7419)
Fault Name Description
This 40-character field provides a place to describe the input
point fa
ult name definition. The description is used to help
document your system (it does not affect application program
operation).
Disable Fault LED
Marking the Disable Fault LED check box disables the fault
LED for this input point on the face of the input module.
Marking this box does not stop the module from line
monitoring the input circuit and updating the state of the
Fault Name variable, it only stops the module from displaying
line faults on the face of the input module. Line faults are still
reported
program through the fault name variable.
to the Regent and are available to the application
This box can be checked for those input points are spare and
have no field switches connected. In this configuration the
line fault LED will always be off. If you do not check this box
for unconnected spare input points, the line fault LED will
always be on.
16
Reset Name
This is the name used in the application program to control
the Reset operation for a latched fire detector input. The
name can be up to 12 charac
Reset Description
ters long.
This 40-character field provides a place to describe the Reset
point definition. The description is used to help document
your system (it does not affect application program operation).
Industrial Control Services
Fire Detector Input Modules
(T7419)
LED Force
This is the name used in the application program to control
the ALARM indicator for the input on the face of the input
module. In some applications it is desirable to latch the alarm
indication for the input after a fire detector has alarmed and
then reset the indication after a fire
detector reset has
occurred. By naming the LED Force bit, you can control the
ALARM indicator through application programming. If
desired, name the LED Force bit, using up to 12-characters.
Programming
Inputs are referenced in the application program through the
tag names defined in the I/O Configuration Editor. When the
fire detector is in the alarm state the input is said to be on, or
have a value of one. In ladder logic, the on state would
produce power flow in a normally open (N.O.) contact.
Field w
iring open circuit or short circuit conditions are
referenced in the application program using the Fault Name
tag names defined in the I/O configuration Editor. If there is
a short or open circuit the Fault Name status is off.
Resetting a Latched Fire Detector
Most typical fire detector input sensors latch when tripped
and need to be reset. A sensor reset occurs when the supply
voltage to the detector is removed. The fire detector input
module provides individual channel reset capability designed
for thi
s purpose. Through application programming, a Reset
bit for each input can be turned on to reset the desired input
channel. When the module receives an input reset signal, the
power to the input circuit is turned off. The front panel alarm
LED will go off and the inputs state reported to the processors
shall remain unchanged. The module will indicate a line fault
for the input (since the loop current is zero with the power
removed).
When the reset signal is turned off, power is applied to the
input and the status LED will report the field input state.
However, the input state reported to the processors will
remain in its last state for an additional period (typically 5
seconds) to all the fire detector to settle. After this delay the
actual field signal shall be reported back to the processors.
PD-7032
Mar-06
17
Fire Detector Input Modules
To program the reset function for a fire detector, you should
program the reset bit to turn on when initiated and remain on
for the time required by the fire detector to reset. Consult the
specifications on your sensors for the required reset time.
(T7419)
Maintenance
No periodic maintenance or calibration is required for the
digital input modules. There are no user replaceable parts
inside these modules.
Safety Considerations
The fire detector input modules are TÜV certified for Risk
Class 5 safety critical inputs. Safety critical configurations
include dual and triple redundant input modules (and sensors
if required) and associated application voting methods.
In safety critical input applications using a single sensor, it is
important that the sensor failure modes be predictable and
well understood, so there is little probability of a failed sensor
not responding to a critical process condition. In such a
configuration, it is important that the sensor be tested
regularly, either by dynamic process conditions that are
verified in the Regent, or by manual intervention testing.
18
Redundant sensors can be used with redundant input
modules to eliminate any single points of failure and extend
fault tolerance to include the sensors.
For additional safety considerations, please refer to the Safety
Considerations section of the Regent User’s Guide.
Industrial Control Services
Fire Detector Input Modules
Safetybus Power
0.85 load units
Number of Inputs
16
Field Circuit Type
Standard 20 volt detector
loop, line monitored and
tested
Field Power
Voltage:
Current:
15 to 40 VDC
1.2 amps, maximum
Nominal Operating Voltage
Module provides regulated
23.5 Vdc for input loop
End of Line Terminator
3.0 Kohm resistor, typical
Quiescent Cu
rrent,
Maximum
3 to 10 mA, typical when
detector in normal state
Detector Alarm
See Load-line
characteristics, page 9.
Reset
Voltage:
Current:
Time
:
<1 volt
<20 mA
Programmable
Test Interval
15 seconds (typical)
Intrinsic Safety
External barrier
Over voltage Protection
27 volts continuous, 500
volts surge transient
Fusing
None (internal current limit
20 mA — no damage with
continual short circuit or
open input)
Isolation
2500 volts minimum (field
wiring
to control logic)
Operating Temperature
0°
to 60° C
(32° to 140° F)
(T7419)
Specifications
PD-7032
Mar-06
19
Storage Temperature
-40°
to 85° C
(-40°
to 185° F)
Operating Humidity
0 to 95% relative humidity,
non-condensing
Vibration
10 to 55 Hz:
0.15", double amplitude
Shock
Operating:
15 g ½ sine wave, 11 msec
Electromagnetic
Interference
•
IEC 801 Part 2 - Electrostatic
Discharges
•
IEC 801 Part 3 - Radiated
Electromagnetic Fields
•
IEC 801 Part 4 - Transients
and Bursts
•
ANSI/IEEE C37.90 - Surge
Withstand Capability
Level 3: Contact discharge of
6 kV
Level 3: 10 V/M, 27 MHz 500 MHz
Level 4: 2 kV, 2.5 kHz for t =
60 seconds
2.5 kV damped 1 MHz sine
wave
4 kV bi-directional impulse,
10
nsec rise time, fast
transient
Safety
Certified to DIN V VDE
0801 for Risk Class 5. Also
designed to meet UL 508 and
CSA 22.2, No. 142-M1981
Heat Dissipation
20 Watts, 70 BTUs/hour
Dimensions
Height:
Width:
Depth:
12.6" (320 mm)
1.27" (32 mm)
10.125" (257 mm)
Weight
3.3 lbs (1.5 kg)
Fire Detector Input Modules
(T7419)
20
Industrial Control Services
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