Krom Schroder FCU 500 Manual

6 Edition 02.17
Technical Information · GB
• For monitoring and controlling central safety functions in multiple
burner systems on industrial furnaces
• Valve proving system for a valve system leak tightness check
(optional)
• Safety temperature monitor (STM) or safety temperature limiter
(STL) (optional)
• Long service life due to replaceable power module for fail-safe
outputs
• Visualization and adaptation to the specific application via the PC
programming and diagnostic software BCSoft to simplify logistics
management
Protective system controls FCU 500, FCU 505

FCU 500, FCU 505 · Edition 02.17 2
▼= To be continued
Protective system controls FCU 500, FCU 505 ......1
Contents ............................................2
1 Application ........................................5
1.1 Application examples ..............................8
1.1.1 ON/OFF rotary impulse control .......................8
1.1.2 Modulating burner control ..........................10
1.1.3 Safety limits (LDS) for modulating burner control ...11
1.1.4 Flame control using the temperature ............... 12
1.1.5 Furnace and zone control ...........................13
2 Certification ......................................14
3 Function ..........................................15
3.1 Connection diagram ..............................15
3.1.1 FCU 500 .............................................15
3.1.2 FCU 505 .............................................16
3.1.3 Assignment of connection terminals ................17
3.2 Program sequence................................19
3.2.1 FCU 500..F0.........................................19
3.2.2 FCU 500..F1, FCU 500..F2..........................20
3.2.3 FCU 505..F1, FCU 505..F2 ...........................21
3.3 Animation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
4 Temperature monitoring......................... 23
4.1 High temperature operation with safety
temperature monitor function (STM function) .......24
4.1.1 With integrated STM ................................24
4.1.2 With external STM...................................25
4.1.3 With integrated and external STM ..................25
4.2 Maximum temperature monitoring with
(flue gas) safety temperature limiter (STL/FSTL
function) ..............................................26
4.2.1 With integrated STL/FSTL ..........................26
4.2.2 With external STL/FSTL ............................26
5 Air control ........................................27
5.1 Controlled air flow ................................28
5.2 Capacity control ..................................29
6 Furnace zone control .............................31
7 Valve proving system ............................ 33
7.1 Tightness control..................................34
7.1.1 Test instant...........................................35
7.1.2 One test volume between 2 gas solenoid valves ....36
7.1.3 One test volume for system tightness ...............39
7.1.4 Two test volumes for system tightness .............. 42
7.1.5 Large test volumes with reduced testing time ......46
7.2 Test period tP..................................... 48
7.2.1 For one test volume Vp1 between 2 gas solenoid
valves ......................................................48
7.2.2 For one test volume Vp1 for system tightness .......48
7.2.3 For two test volumes for system tightness (Vp1 +
Vp2)........................................................49
7.2.4 Extended valve opening time 1 tL1 ..................50
7.2.5 Measurement time tM...............................53
7.3 Proof of closure function ..........................57
8 BCSoft........................................... 58
9 Fieldbus communication via Ethernet . . . . . . . . . . . 59
9.1 FCU and bus module BCM ...................... 60
9.2 Configuration, planning ..........................61
9.2.1 Profinet/Device master data file (GSD) ..............61
9.2.2 Modbus TCP..........................................61
9.2.3 Modules/Registers for process data................ 62
9.2.4 Device parameters and statistics . . . . . . . . . . . . . . . . . . . 68
10 Program step/status ........................... 69
11 Fault signalling ................................. 70
12 Parameters ......................................74
12.1 Scanning the parameters........................79
12.2 Safety limits .....................................79
12.2.1 Emergency stop....................................79
12.2.2 High gas pressure protection ......................80
12.2.3 Low gas pressure protection.......................80
12.2.4 Low air pressure protection .........................81
Contents

FCU 500, FCU 505 · Edition 02.17 3
▼= To be continued
12.2.5 Safety time during operation tSB ...................81
12.3 High temperature operation.....................82
12.3.1 Temperature monitoring mode ....................82
12.3.2 Thermocouple......................................83
12.3.3 Temperature difference limit value ................83
12.3.4 STM limit value (high temperature operation).....84
12.3.5 STL/FSTL limit value (system protection).........84
12.3.6 Temperature hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
12.3.7 Pre-purge during high temperature operation ....86
12.4 Air control........................................87
12.4.1 Fan in the event of fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87
12.4.2 Fan run-up time tGV ................................87
12.4.3 Fan ready for operation .............................87
12.4.4 Air monitoring during controlled air flow...........88
12.4.5 Pre-purge time tPV .................................88
12.4.6 Air flow monitoring during pre-purge ..............89
12.4.7 Post-purge time tPN ...............................89
12.4.8 Air flow monitoring during post-purge.............90
12.4.9 Capacity control.....................................91
12.4.10 Running time selection ..........................100
12.4.11 Running time ....................................100
12.4.12 Controller enable signal delay time tRF .........101
12.4.13 Minimum enable time ...........................101
12.4.14 Burner operating signal..........................101
12.4.15 Controller enable time limit......................102
12.4.16 Capacity control (bus) ...........................103
12.5 Valve check ....................................108
12.5.1 Valve proving system..............................108
12.5.2 Relief valve (VPS) .................................108
12.5.3 Tightness control test volume ....................109
12.5.4 Pressure reduction Vp2 ...........................110
12.5.5 Opening time relief valve V3 ......................110
12.5.6 Measurement time Vp1 ...........................110
12.5.7 Measurement time Vp1 and Vp2 ..................110
12.5.8 Valve opening time 1 tL1 ..........................112
12.5.9 Valve opening time 2 tL2 ..........................112
12.6 Behaviour during start-up .....................113
12.6.1 Minimum pause time tMP .........................113
12.6.2 Switch-on delay time tE..........................113
12.6.3 Filling time before start-up .......................113
12.7 Manual mode ..................................114
12.7.1 Operating time in Manual mode ..................114
12.8 Functions of terminals 51, 65, 66, 67 and 68 .115
12.8.1 Function of terminal 51 ...........................115
12.8.2 Function of terminal 65 ...........................116
12.8.3 Function of terminal 66 ...........................116
12.8.4 Function of terminal 67 ...........................117
12.8.5 Function of terminal 68 ...........................117
12.9 Password ......................................118
12.10 Fieldbus communication ....................118
13 Selection ......................................119
13.1 Type code ......................................119
14 Project planning information ..................120
14.1 Installation.....................................120
14.2 Commissioning ................................120
14.3 Electrical connection .......................... 121
14.3.1 OCU ...............................................121
14.3.2 Safety current inputs..............................122
14.4 High temperature operation ...................123
14.4.1 Safety temperature monitor (STM) ...............123
14.4.2 Safety temperature limiter (STL)..................124
14.4.3 Temperature sensors (double thermocouples) . . .124
14.4.4 Thermocouples....................................124
14.4.5 PFHDvalue for STM/STL temperature module
and thermocouple........................................126
14.5 Safety interlock output ........................ 127
14.5.1 Safety interlock output in the case of higher
power requirement .......................................127
14.5.2 BCU with power supply for valves and ignition
transformer via safety interlocks.........................128
14.6 Actuators ......................................129
14.6.1 IC 20 ...............................................129
14.7 Air control ......................................129
14.8 Parameter chip card ...........................130
14.9 System leak tightness check ..................130
15 Accessories.................................... 131

FCU 500, FCU 505 · Edition 02.17 4
▼= To be continued
15.1 BCSoft ..........................................131
15.1.1 Opto-adapter PCO 200 ...........................131
15.1.2 Bluetooth adapter PCO 300 ......................131
15.2 OCU.............................................131
15.3 Connection plug set ...........................132
15.4 Stickers for labelling ...........................132
15.5 “Changed parameters” stickers................132
16 OCU ...........................................133
16.1 Application.....................................133
16.2 Function .......................................134
16.2.1 Manual mode......................................135
16.3 Electrical connection ..........................135
16.4 Installation.....................................136
16.5 Selection.......................................136
16.6 Technical data for OCU . . . . . . . . . . . . . . . . . . . . . . . . 136
17 BCM 500 ...................................... 137
17.1 Application ......................................137
17. 2 F un c ti o n ........................................137
17.3 Electrical connection ...........................137
17.4 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
17. 5 S e l e c ti on .......................................138
17.6 Technical data..................................138
18 Technical data .................................139
18.1 Electrical data .................................139
18.2 Mechanical data ...............................140
18.3 Environment ...................................140
18.4 FCU..H1........................................140
18.5 Dimensions ....................................140
18.6 Safety-specific characteristic values...........141
18.7 Converting units ............................... 142
19 Maintenance ..................................143
20 Legend ........................................144
21 Glossary.......................................145
21.1 Safety shut-down..............................145
21.2 Fault lock-out..................................145
21.3 Warning signal.................................145
21.4 Timeout........................................146
21.5 Lifting .........................................146
21.6 Diagnostic coverage DC.......................146
21.7 Operating mode ...............................146
21.8 Safe failure fraction SFF........................147
21.9 Probability of dangerous failure PFHD........147
21.10 Mean time to dangerous failure MTTFd.....147
Feedback .........................................148
Contact...........................................148

FCU 500, FCU 505 · Edition 02.17 5
Application
1 Application
FCU with plug-in connection terminals
Protective system control FCU 500 is designed to mon-
itor and control central safety functions, e.g. gasmin.,
gasmax., airmin., pre-purge, tightness test, high tempera-
ture operation or start enable for burner control units, in
multiple burner systems on industrial furnaces. In a fur-
nace and zone control system, the FCU 500 assumes
central functions. The FCU 505 is used to monitor local
safety functions and to control the zone capacity. If the
centrally checked safety requirements, e.g. pre-purge,
flow detector and pressure switch check, have been
met, the FCUs issue the start enable signal to the burn-
er control units.
The FCU is optionally available with integrated safety
temperature monitor or safety temperature limiter,
integrated tightness control and with an interface for
controlling the capacity of actuators or a frequency
converter interface.
The program status and device parameters can be read
directly from the unit. The FCU can be activated manu-
ally using the integrated Manual mode for setting and
diagnostic purposes.
Thanks to the optionally integrated valve proving sys-
tem, the valves can be checked for leaks by querying
an external gas pressure switch or it can be checked
whether the gas valve on the inlet side is closed.
Using the BCSoft program, the parameters, analysis
and diagnostic information can be read from the FCU
via the optionally available opto-adapter. All valid pa-
rameters are saved on an integrated parameter chip
card. The parameter chip card can be removed from the
old unit and inserted into a new FCU to transfer the pa-
rameters, for example when replacing the unit.
▼

FCU 500, FCU 505 · Edition 02.17 6
Application
The monitored outputs for the actuator and valves are
accommodated in a plug-in power module. This can
simply be replaced if necessary.
Once the plug-in power module has been removed, the param-
eter chip card and fuses are accessible.
The FCU can be installed on a DIN rail in the control
cabinet. Plug-in connection terminal strips on the FCU
make it easier to install and remove.
The external operator-control unit OCU is available as
an option for the protective system controls. The OCU
can be installed in the control cabinet door instead of
standard control units. The program status, statistics,
parameter values or fault messages can be read on
the OCU. For burner adjustment, the operating points
can be approached conveniently in Manual mode using
the operator-control unit.
Thanks to the operator-control unit OCU, display functions and
operation of the FCU can be relocated to the control cabinet
door.
The optional bus module BCM 500 makes it possible
to connect the FCU to a fieldbus interface in a Profinet
or Modbus TCP network. Networking via the fieldbus
enables multiple FCUs to be controlled and monitored
by an automation system (e.g. PLC). The bus module is
prepared for DIN rail installation. It is pushed on to the
FCU from the side.
The address for the fieldbus communication is set using three
code switches.

FCU 500, FCU 505 · Edition 02.17 7
Application
Roller hearth kiln in the ceramics
industry
Shaft melting furnace Smelting and holding furnace

FCU 500, FCU 505 · Edition 02.17 8
Application
1.1 Application examples
1.1.1 ON/OFFrotaryimpulsecontrol
For processes which require a turn-
down of more than 10:1 and/or
those which require heavy circula-
tion of the furnace atmosphere to
ensure a uniform temperature, e.g.
heat treatment furnaces operating
at low and medium temperatures in
the metallurgical industry.
With ON/OFF cyclic control, the
capacity supplied to the process is
controlled by means of a variable
ratio of the operating time to the
pause time. In this type of control,
the burner output pulse frequency
always maintains full momentum
and results in maximum convection
in the furnace chamber, even with
regulated heating.
The pneumatic ratio control sys-
tem controls the gas pressure on
the burner proportionally to the air
pressure and thus maintains a con-
stant air/gas ratio. At the same time,
it acts as a low air pressure protec-
tion device.
▼
M
PZL PZH PZ
PZL PDZ
TE
M
BCU 460..L
BCU 460..L
FCU 500..F0
µC P
DG DG DG
VAS VAS
VAS
VCG
VCG
VR..L
VR..L
DG DG
DGmin DG max
49 15 131450
45
47 4858
>750°
pu/2
ϑ1
46
2
3
DLmin DL Purge
STM

FCU 500, FCU 505 · Edition 02.17 9
Application
The ignition and monitoring of the
individual burners is ensured by
burner control unit BCU 460..L.
The centrally checked safety func-
tions such as pre-purge, tightness
test, flow detector and pressure
switch check (gasmin., gasmax.,
airmin.) are provided by the FCU 500.
M
PZL PZH PZ
PZL PDZ
TE
M
BCU 460..L
BCU 460..L
FCU 500..F0
µC P
DG DG DG
VAS VAS
VAS
VCG
VCG
VR..L
VR..L
DG DG
DGmin DG max
49 15 131450
45
47 4858
>750°
pu/2
ϑ1
46
2
3
DLmin DL Purge
STM

FCU 500, FCU 505 · Edition 02.17 10
Application
1.1.2 Modulating burner control
For processes that do not require
heavy circulation in the furnace, e.g.
aluminium smelting furnaces.
This system is suitable for process-
es in which infiltrated air may flow
into the furnace through switched
off burners. The capacity can be
adjusted continuously by activating
the air control valve (analogue or
3-point step signal). The pneumatic
ratio control system controls the
gas pressure proportionally to the
air pressure and thus maintains a
constant air/gas ratio. At the same
time, it acts as a low air pressure
protection device.
One burner control unit per burner
is required for ignition and monitor-
ing.
The centrally checked safety func-
tions such as pre-purge, setting the
valve to ignition position via a but-
terfly valve control system, tight-
ness test, flow detector and pres-
sure switch check (gasmin., gasmax.,
airmin.) are provided by the FCU 500.
FCU 500..F1
µC
P
DG DG DG
VAS VAS
VCG
VCG
DGmin DG max
49 15 131450
53
45
47 4858
pu/2
M
PZL PZH PZ
PZL PDZ
TE
BCU 460..L
BCU 460..L
M
M
TC
90°➔0°
0°➔90°
54
55
VAS
DGDG
>750°
ϑ1
2
3
DLmin DL Purge
46
STM

FCU 500, FCU 505 · Edition 02.17 11
Application
1.1.3 Safety limits (LDS) for
modulating burner control
The centrally checked safety func-
tions such as pre-purge, setting the
valve to ignition position via a but-
terfly valve control system, tight-
ness test, flow detector and pres-
sure switch check (gasmin., gasmax.,
airmin.) are provided by the FCU 500.
The capacity can be adjusted con-
tinuously by activating the control
element (analogue or 3-point step
signal).
To ensure that the correct air vol-
ume is available for ignition (start
fuel flow rate) when starting the
burners, the FCU sends the burner
start enable signal to the BCUs via
the “LDS (limits during start-up)”
output.
The circuit design of the safety
interlock and LDS outputs on the
FCU and the corresponding in-
puts on the BCUs ensures that the
burners can only start if the safety
interlocks and the LDS output have
enabled burner start-up.
FCU 500..F1
µC
P
DG DG DG
VAS VAS
VCG
VCG
DGmin DG max
49 15 131450
53
45
47 4858
pu/2
M
PZL PZH PZ
PZL PDZ
TE
BCU 560..F0
M
M
TC
90°➔0°
0°➔90°
54
55
VAS
DGDG
>750°
ϑ1
2
3
DLmin DL Purge
66
BCU 560..F0
66
16
57
STM

FCU 500, FCU 505 · Edition 02.17 12
Application
1.1.4 Flame control using the temperature
FCU 500..H1
M
HT
18
HT
HT
BCU 56x..D
49
5
µC
BCU 56x..D
49
5
µC
5-8
STM
In high temperature systems (temperature > 750°C),
the flame may be controlled indirectly via the tempera-
ture. As long as the temperature in the furnace chamber
is below 750°C, the flame must be controlled by con-
ventional methods.
If the temperature in the furnace chamber rises above
the spontaneous ignition temperature of the gas/air
mixture (> 750°C), the FCU signals to the burner control
units via the fail-safe HT output that the furnace sys-
tem is in High temperature mode (HT). When the HT in-
put is activated, the burner control units switch to High
temperature mode. They operate without evaluation of
the flame signal and their internal flame control system
is non-functional.
If the furnace temperature falls below the spontaneous
ignition temperature (< 750°C), the FCU disconnects
the HT output from the electrical power supply. There
is no active signal at the HT inputs of the burner control
units. The flame signals are monitored once again by
the UV sensor or flame rod.
In the event of a fault in a temperature monitoring com-
ponent (e.g. sensor discontinuity, sensor short-circuit)
or in the event of a mains failure, the flame control task
is transferred to the burner control units.

FCU 500, FCU 505 · Edition 02.17 13
FCU 500..F0
µC
P
49 15 131450 45
4758 48
PZL PZH PZ
PZL PDZ
M
BCU
V1
BCU
V1
FCU 505..F1
µC
54 55
53
M
1
2
3
BCU
V1
BCU
V1
FCU 505..F1
µC
54 55
53
1
1
66
66
46
46
67
+24V
L1
+24V
L1
M
57
17
4
4
Application
1.1.5 Furnace and zone control
The FCU 500 (furnace FCU) performs central tasks
such as checking the safety interlocks, fan control, sys-
tem leak tightness check and pre-purge.
It signals to the FCU 505 in the zones that the butterfly
valves can be moved to the purge position. Signals are
sent to the butterfly valves by the FCU 505. The but-
terfly valves move into position. A signal is sent to the
FCU 505 via their safety interlock input that the central
FCU 500 has issued the enable signal for the burners.

FCU 500, FCU 505 · Edition 02.17 14
Certification
2 Certification
Certificates – see Docuthek.
Certified pursuant to SIL
For systems up to SIL 3 pursuant to EN 61508.
Pursuant to EN ISO 138491:2006, Table 4, the FCU
can be used up to PL e.
EU certified pursuant to
– Gas Appliances Directive (2009/142/EC) in conjunc-
tion with EN 298, EN 1643
Meets the requirements of the
– Low Voltage Directive (2006/95/EC),
– EMC Directive (2004/108/EC).
FM approved
Factory Mutual Research Class: 7610 “Combustion Safe-
guards and Flame Sensing Systems”. Suitable for applica-
tions pursuant to NFPA 86. www.approvalguide.com
ANSI/CSA approved
American National Standards Institute/Canadian
Standards Association –ANSI Z21.20/CSA C22.2,
No. 199
www.csagroup.org –Class number: 333501 (natural
gas, propane), 333581 (natural gas, LPG).
Eurasian Customs Union
The product FCU 500 meets the technical specifica-
tions of the Eurasian Customs Union.

FCU 500, FCU 505 · Edition 02.17 15
Function
3 Function
3.1 Connection diagram
3.1.1 FCU 500
Detailed connection diagrams for actuators and fre-
quency converters, see from page 91 (Capacity con-
trol)
Electrical connection, see page 120 (Project planning
information)
Explanation of symbols, see page 144 (Legend)
1 2 3 46 47 48 49 50 4 67 52 45 51 65 66 68
41 4216 17 18 57
13 14 1553 54 55 56
62 61 5 6 7 8 11 12
N
P
HT
ϑ
0 V
L1
V1
V2
V3
LDS
FCU 505
+ - + -
K2
K1
k11 k21
3,15AT
µC
24V
DC
88
M
+24 V
PZL
PDZ
PZL
PZH
P70
P71
P73
P72
P69
PZL
PDZ
PZL
PZH
P70
P71
P73
P72
pu
2GZL
PZL
58
5AT
44
FCU 500
Airmin
Air
STM/
STL
Gasmax
Gasmin
0.6 × IN
IN× 0.6

FCU 500, FCU 505 · Edition 02.17 16
Function
3.1.2 FCU 505
Detailed connection diagrams for actuators and fre-
quency converters, see from page 91 (Capacity con-
trol)
Electrical connection, see page 120 (Project planning
information)
Explanation of symbols, see page 144 (Legend)
1 2 3 46 47 48 49 50 4 67 52 45 51 65 66 68
41 4216 17 18 57
13 14 1553 54 55 56
62 61 5 6 7 8 11 12
N
P
HT
ϑ
0 V
L1
V1
V2
V3
LDS
FCU 505
+ - + -
K2
K1
k11 k21
3,15AT
µC
24V
DC
88
M
+24 V
PZL
PDZ
PZL
PZH
P70
P71
P73
P72
P69
PZL
PDZ
PZL
PZH
P70
P71
P73
P72
pu
2GZL
PZL
Airmin
Air
STM/
STL
Gasmax
Gasmin
0.6 × IN
IN× 0.6

FCU 500, FCU 505 · Edition 02.17 17
Function
3.1.3 Assignment of connection terminals
Terminal Type Designation Function
1
24 V DC input
Start-up signal Signal applied: FCU start; no signal: FCU stop
2 Controlled air flow
Signal applied: fan is started to supply air to the combustion chamber for cooling, for
example. Only functional in standby. The function is deactivated as soon as a signal is
received at terminal 1 (FCU start).
3Remote reset Input for external signal (button) to reset the unit after a fault lock-out
4Operating signal Signal from the burner control units to inform the FCU that a sufficient number of burners is
available for temperature control
5, 6
and
7, 8
Double
thermocouple
Safety temperature monitor and/or
safety temperature limiter
Monitor the spontaneous ignition temperature of the gas/air mixture in High temperature
mode and/or the maximum furnace or flue gas temperature using the integrated
temperature module of the FCU..H1
11, 12 V AC input Supply voltage Voltage to operate the FCU,
11 = phase (L1), 12 = neutral conductor (N)
13
Safety circuit output
Gas valve V1 Connection of phase for gas valve V1
14 Gas valve V2 Connection of phase for gas valve V2
15 Gas valve V3 Connection of phase for gas valve V3
57 Safety interlocks (limits) Safety enable signal to the burner control units
16 Safety limits (limits during start-up)
To ensure that the correct air volume is available for ignition (start fuel flow rate) when
starting the burners, the FCU sends the burner start enable signal to the burner control
units via this output.
17 Purge Signal to FCU 505 or burner control units to inform them that purge is in process
18 High temperature operation Enable signal from the FCU indicating that the furnace system is in High temperature mode
41 24 V DC output Fault Fault signalling output, 24 V DC, max. 0.1 A
42 Operating signal Operation signalling output, 24 V DC, max. 0.1 A
44 24 V DC input Fan ready for operation Feedback signal from fan indicating readiness for operation, see Parameter 31
▼

FCU 500, FCU 505 · Edition 02.17 18
Function
Terminal Type Designation Function
45
Safety circuit input
Valve proving system Connection for the sensor of the valve proving system (tightness control pressure switch or
POC switch for checking the closed position).
46 Controller enable/emergency stop Connection for higher-level safety devices and interlocks (e.g. emergency stop, safety
temperature monitor), see Parameter 10
47 Minimum air pressure Connection for pressure switch to monitor the minimum air pressure, see
Parameter 15
48 Minimum air flow Connection for a sensor to monitor the minimum air flow during pre-purge or post-purge,
see Parameters 35, 38
49 Minimum gas pressure Connection for pressure switch to monitor the minimum gas pressure, see Parameter 13
50 Maximum gas pressure Connection for pressure switch to monitor the maximum gas pressure, see Parameter 12
51, 65,
66, 67,
68
Programmable inputs The terminals can be assigned a function using parameters. To do so, logical AND gatings
with terminals 46, 47, 48, 49 or 50 are possible.
52 Feedback from actuator/frequency
converter Connection for the position feedback signal from the actuator/frequency converter
53, 54,
55, 56 V AC output
Capacity control Connection for capacity control using an actuator or frequency converter,
see Parameter 40 to 47
58 Fan Connection for fan control. Alternatively, this output can be used to activate a valve to check
the function of the air pressure switch.

FCU 500, FCU 505 · Edition 02.17 19
Function
3.2 Program sequence
3.2.1 FCU 500..F0
Example of application, see page 8 (ON/OFF rotary
impulse control)
Switch on the FCU
▼
In the event of fault signal: reset
▼
00 Start-up position/standby
▼
H0 Start-up with ϑsignal
▼
Switch-on delay time tErunning (parameter 63)
Safety interlocks check
▼
01 Fan run-up time tGV running (parameter 30)
Pre-purge starts
▼
1Air flow monitoring
▼
P1 Pre-purge time tPV running (parameter 34)
Tightness test (if equipped with TC)
▼
08
Gas enable via valves V1 and V2
Enable signal to burner control units for the burner start via the “safety
interlock” output
▼
Operation

FCU 500, FCU 505 · Edition 02.17 20
Function
3.2.2 FCU 500..F1, FCU 500..F2
Example of application, see page 10 (Modulating
burner control)
Switch on the FCU
▼
In the event of fault signal: reset
▼
00 Start-up position/standby
▼
H0 Start-up with ϑsignal
▼
Switch-on delay time tErunning (parameter 63)
Safety interlocks check
▼
01 Fan run-up time tGV running (parameter 30)
Pre-purge starts
▼
AActuator moves to the position for maximum capacity
▼
1Air flow monitoring
▼
P1 Pre-purge time tPV running (parameter 34)
Tightness test (if equipped with TC)
▼
AActuator moves to the position for ignition capacity
▼
H7
Gas enable via valves V1 and V2
Enable signal to burner control units for the burner start via the
“safety interlock” output
▼
H8 Controller enabler signal delay time tRF running
▼
08 Operation/controller enable