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Krom Schroder
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BCU 560
Technical Information
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Krom Schroder BCU 560, BCU 565 Technical Information

Burner control units BCU 560, BCU 565

Technical Information · GB
6 Edition 02.16
• For monitoring and controlling modulating or staged burners for multiple burner applications with a central air supply
• For directly ignited burners of unlimited capacity in intermittent or continuous operation
• Optionally with valve proving system
thermal NO
• Flexible range of applications due to parameterization possibilities
• PROFINET fieldbus connection using optional bus module
• Assume safety functions pursuant to EN746-2
• EU certified
• Certified for systems up to SIL 3 and PL e
x
®
operating mode to reduce the formation of

Contents

Burner control units BCU 560, BCU 565 ............... 1
Contents........................................2
1 Application.....................................5
1.1 Examples of application..........................7
1.1.1 Single-stage-controlled burner........................7
1.1.2 Two-stage-controlled burner ........................ 8
1.1.3 Modulating-controlled burner ........................9
1.1.4 Flame control using the temperature .................10
1.1.5 menox
1.1.6 PROFINET connection using bus module BCM ..........12
1.1.7 ON/OFF rotary impulse control for burners up to 360kW . 13
1.1.8 Modulating burner control . . . . . . . . . . . . . . . . . . . . . . . . . .14
2 Certification ................................... 15
3 Function...................................... 16
3.1 Connection diagram ...........................16
3.1.1 BCU560..F3 with ionization control in double-electrode
operation ............................................16
3.1.2 BCU560..F1......................................17
3.1.3 BCU560..F2 .....................................18
3.1.4 BCU565..F3 with ionization control in double-electrode
operation ............................................19
3.1.5 BCU565..F1..................................... 20
3.1.6 BCU565..F2 .....................................21
3.1.7 Flame control ................................... 22
3.2 BCU 560 program sequence ....................23
3.3 BCU 565 program sequence ....................24
4 Air control ....................................25
4.1 Capacity control ...............................26
4.1.1 BCU..F1/F2 ...................................... 26
4.1.2 BCU..F3 .........................................27
5 menox® low NOx mode .........................28
5.1 System structure and function....................28
5.2 BCU..D2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
6 Valve proving system ........................... 31
®
mode to reduce NOx formation ..............11
6.1 Tightness control ..............................31
6.1.1 Test instant...................................... 32
6.1.2 Program sequence............................... 33
6.1.3 Test period t
6.1.4 Opening time t
6.1.5 Measurement time t
................................... 35
P
................................. 35
L
............................ 35
M
6.2 Proof of closure function........................38
6.2.1 Program sequence............................... 38
7 BCSoft .......................................39
8 Profinet ......................................40
8.1 BCU and bus module BCM......................41
8.2 GSD file for PLC configuration....................42
8.2.1 Modules for cyclic data exchange .................. 43
8.2.2 Indexes for acyclic communication ................. 48
9 Program step/status............................49
10 Fault signalling................................50
11 Parameters...................................53
11.1 Scanning the parameters.......................58
11.2 Flame control ................................58
11.2.1 Burner 1 FS1 flame signal switch-off threshold......... 58
11.2.2 Flame control................................... 59
11.2.3 High temperature operation ...................... 60
11.3 Behaviour during start-up ......................62
11.3.1 Burner 1 start-up attempts......................... 62
11.3.2 Burner application............................... 63
11.3.3 Safety time 1 t
11.3.4 Flame proving period 1 t
SA1 ............................................71
........................71
FS1
11.4 Behaviour during operation.....................72
11.4.1 Restart..........................................72
11.4.2 Minimum operating time t
........................73
B
11.5 Safety limits ..................................74
11.5.1 Low air pressure protection ....................... 74
11.5.2 Air pressure cut-out delay ........................ 74
11.5.3 Safety time during operation .......................75
11.6 Air control ...................................76
BCU 560, BCU 565 · Edition 02.16 2
= To be continued
▼
Contents
11.6.1 Pre-purge time tPV ................................76
11.6.2 Air flow monitoring during pre-purge ................76
11.6.3 Pre-ventilation time t
11.6.4 Post-ventilation time t
11.6.5 Capacity control..................................78
11.6.6 Running time selection ........................... 85
11.6.7 Running time ................................... 85
11.6.8 Low fire over-run ................................ 86
11.6.9 Controller enable signal delay time t
11.6.10 Air actuator control ..............................87
11.6.11 Air actuator can be activated externally on start-up ... 89
11.6.12 Air actuator in the event of fault ................... 89
11.6.13 Capacity control (bus) ........................... 90
11.7 menox
11.7.1 menox pre-ventilation time t
11.7.2 Switchover to menox
® ................................................95
VL..................................... 77
NL ................................... 77
.............. 86
RF
.................... 95
VLM
®
operating mode ............. 95
11.8 Valve check..................................96
11.8.1 Valve proving system ............................ 96
11.8.2 Relief valve (VPS) ................................ 96
11.8.3 Measurement time V
11.8.4 Valve opening time t
...........................97
p1
............................97
L1
11.9 Behaviour during start-up ......................98
11.9.1 Minimum pause time tBP ......................... 98
11.10 Manual mode ...............................99
11.10.1 Operating time in Manual mode .................. 99
11.11 Functions of terminals 50, 51, 65, 66, 67 and 68 ..100
11.11.1 Function of terminal 50 ...........................100
11.11.2 Function of terminal 51 ...........................100
11.11.3 Function of terminal 65 ..........................100
11.11.4 Function of terminal 66 ..........................101
11.11.5 Function of terminal 67...........................102
11.11.6 Function of terminal 68 ..........................103
11.12 Password..................................104
11.13 Fieldbus communication .....................104
12 Selection.................................... 105
12.1 Type code ..................................105
13 Project planning information....................106
13.1 Installation..................................106
13.2 Commissioning .............................106
13.3 Electrical connection ......................... 107
13.3.1 OCU ..........................................107
13.3.2 Safety current inputs.............................108
13.3.3 UVD control....................................109
13.4 Actuators .................................. 110
13.4.1 IC20..........................................110
13.5 Parameter chip card ......................... 110
13.6 Overload protection.......................... 110
13.7 Calculating the safety time t
SA.........................111
13.8 Fourth or switchable gas valve on BCU..F3 ........112
14 Accessories ..................................113
14.1 BCSoft ..................................... 113
14.1.1 Opto-adapter PCO 200 ...........................113
14.1.2 Bluetooth adapter PCO 300 .......................113
14.2 OCU ...................................... 113
14.3 Connection plug set.......................... 113
14.4 Stickers for labelling.......................... 114
14.5 “Changed parameters” stickers ................ 114
15 OCU ........................................115
15.1 Application ................................. 115
15.2 Function ....................................116
15.2.1 Manual mode ..................................116
15.3 Electrical connection ..........................117
15.4 Installation ..................................117
15.5 Selection ....................................117
15.6 Technical data for OCU ....................... 118
16 BCM 500 ....................................119
16.1 Application ................................. 119
16.2 Function ................................... 119
16.3 Electrical connection ......................... 119
16.4 Installation ................................. 119
16.5 Selection ...................................120
16.6 Technical data ..............................120
BCU 560, BCU 565 · Edition 02.16 3
Contents
17 Technical data ................................121
17.1 Electrical data ............................... 121
17.2 Mechanical data ............................122
17.3 Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
17.4 Dimensions.................................122
17.5 Safety-specific characteristic values .............123
17.6 Converting units .............................124
18 Maintenance ................................ 125
19 Legend ..................................... 126
20 Glossary ................................... 127
20.1 Safety time on start-up t
20.2 Ignition time t
............................. 127
Z
20.3 Safety time during operation t
20.4 Safety interlocks ............................ 127
20.5 Safety shut-down ........................... 127
20.6 Safety shut-down with subsequent fault lock-out
(fault lock-out) .................................. 127
20.7 Warning signal .............................128
20.8 Timeout ...................................128
20.9 Lifting .....................................128
20.10 Air valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
20.11 Diagnostic coverage DC .....................128
20.12 Operating mode ...........................128
20.13 Safe failure fraction SFF ......................129
20.14 Probability of dangerous failure PFH
20.15 Mean time to dangerous failure MTTF
Feedback .....................................130
Contact.......................................130
.................... 127
SA1
SB ..................... 127
.........129
D
........129
d
BCU 560, BCU 565 · Edition 02.16 4

1 Application

▼
Burner control unit with plug-in spring force connection terminals
Burner control units BCU 560 or BCU 565 control, ignite and monitor gas burners in intermittent or continuous operation. They can be used for directly ignited industrial burners of unlimited capacity. The burners may be modulating-controlled or stage-controlled. Their fast reaction to various process requirements makes the BCUs suitable for frequent cycling operation.
On industrial furnaces, they reduce the load on the central furnace control by taking over tasks that relate to the burner, for example they ensure that the burner ignites in a safe condition when it is restarted.
The air control on the BCU..F1, F2 or F3 assists the furnace control for cooling, purging and capacity control tasks.
The burner control units have an interface via which an air valve or actuator (IC20, IC40 or RBW) can be controlled for staged or modulating burner capacity control.
The BCU 565..F3 is equipped with air flow monitoring and
pre- and post-ventilation for use on self recuperative burners.
The program status, the unit parameters and the level of the
flame signal can be read directly from the unit. The burner or a connected control element can be activated manually using the integrated Manual mode for setting and diagnostic purposes.
Thanks to the optionally integrated valve proving system, 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 a BCU via the optionally available opto-adapter. All valid parameters are saved on an integrated parameter chip card. The parameter chip card can be removed from the old unit and inserted into a new BCU to transfer the parameters, for example when replacing the unit.
BCU 560, BCU 565 · Edition 02.16 5
Application
The monitored outputs for the actuator and valves are ac- commodated in a plug-in power module. This can simply be replaced if necessary.
Once the plug-in power module has been removed, the parameter chip card and fuses are accessible.
The BCU can be installed on a DIN rail in the control cabinet. Plug-in connection terminal strips on the BCU make it easier to install and remove.
The external operator-control unitOCU is available as an option
for the burner control units. The OCU can be installed in the control cabinet door instead of standard control units. The program status 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.
The address for the fieldbus communication is set using
three code switches.
The optional bus module BCM500 makes it possible to con-
nect the BCU to a fieldbus interface in a PROFINET network. Networking via the fieldbus enables multiple BCUs 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 BCU from the side.
Thanks to the operator-control unitOCU, display functions and operation of the BCU can be relocated to the control cabinet door.
BCU 560, BCU 565 · Edition 02.16 6
Application
FCU 500
HT
P
Process control (PCC)
ϑ
A
1 2 3
38371817
BCU 565..F3
46
µC
49
50
47
V1 V2
VG
VG..L
PLC
VMV
ECOMAX
41
42
13 14
9
10
VR..R
TZI/TGI
PDZ
DG

1.1 Examples of application

1.1.1 Single-stage-controlled burner

Control: ON/OFF. The gas/air mixture is adjusted to the requirements of the
applications using the parameters of pre-ventilation and post- ventilation. The pressure switch monitors the air flow in the air supply line or in the flue gas exhaust.
BCU 560, BCU 565 · Edition 02.16 7
Application > Examples of application
Process control (PCC)
FCU 500
HT
P
ϑ
38371817
BCU 560..C0F3
46
µC
49
50
10
1 2 3
PLC
A
41
42
13 14
9 7
V1 V2
VAS VAG
VR..L

1.1.2 Two-stage-controlled burner

Control: ON/OFF or High/Low
The BCU provides the cooling and purg-
ing processes. The burner starts at low­fire rate. When the operating state is reached, the BCU advises the control unit. Depending on the parameter set­ting, the air valve is actuated to open and close by the program or externally via the input at terminal 2.
TZI/TGI
UVS
BCU 560, BCU 565 · Edition 02.16 8
Application > Examples of application
Process control (PCC)
FCU 500
DI
P
ϑ
38371817
BCU 560..C0F1
46
µC
49
50
52 53 54 55 56
1 2 3
PLC
A
41
42
13 14 15
9 7
V1
VAS VAG
VAS 1

1.1.3 Modulating-controlled burner

Control: continuous
V3
The BCU provides the cooling and purg-
ing processes. The BCU moves the but­terfly valve for air to ignition position. The
V2
burner starts at low-fire rate, a three­point step controller controls the burner capacity via the butterfly valve for air after the operating state has been signalled.
TZI/TGI
UVS
M
BCU 560, BCU 565 · Edition 02.16 9
Application > Examples of application
FCU 500..H1
M
HT
18
HT
HT
BCU 56x..D
49
5
µC
BCU 56x..D
49
5
µC
5-8
STM

1.1.4 Flame control using the temperature

In high temperature systems (temperature >750°C), the flame may be controlled indirectly via the temperature. As long as the temperature in the furnace chamber is below 750°C, the flame must be controlled by conventional 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 system is in High tempera- ture mode (HT). When the HT input is activated, the burner control units switch to High temperature mode. They operate without evaluating the flame signal and their internal flame control 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 longer an active signal at the HT inputs of the burner control units. The flame signals are monitored once again by the UV sensor or ioniza­tion electrode.
In the event of a fault in a temperature monitoring component (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.
BCU 560, BCU 565 · Edition 02.16 10
Application > Examples of application

1.1.5 menox® mode to reduce NOx formation

Process Control (PCC)
STM
AKT
M
IC 40 + BVH
VAD
BCU 565..D2
PZL
VAS..L
DG
VMV
TZI/
TGI
BIC..M
The burner control unit BCU 565 switches the burner BIC..M ON/OFF in cycles. Burner BIC..M is controlled without pneu- matic air/gas ratio control system. The gas supply pressure is controlled by the gas pressure regulatorVAD; the required burner capacity is set using the fine-adjusting valveVMV. The capacity is controlled by actuator IC40 and butterfly valveBVH. An air pressure switch upstream of the burner monitors the functioning of the butterfly valve. In addition, air/gas ratio monitoring for the zone or the furnace is required.
As soon as the safety temperature monitor STM signals a furnace temperature of ≥850°C(1562°F), the burner can be switched to flameless combustion (menox® low NOx mode) to significantly reduce NOx emissions.
Switching to menox
®
low NOx mode eliminates the counter­pressure by the flame in the ceramic tubeTSC. At a constant gas supply pressure, the gas volume increases by approxi­mately15%. In menox® low NOx mode, the butterfly valve moves to a smaller open position which has been adapted to the pressure ratios.
BCU 560, BCU 565 · Edition 02.16 11
Application > Examples of application
1
2 3
BCU 56x
BCM
BCU 56x
BCM
BCU 56x
BCM
PROFINET
L1
BUS
FCU
P
HT
PLC

1.1.6 PROFINET connection using bus module BCM

The bus system transfers the control signals from the auto- mation system (PLC) to the BCU/BCM for starting, resetting, controlling the air valve, purging the furnace or for cooling and heating during operation. In the opposite direction, it sends operating status, the level of the flame signal and the current program status.
Control signals that are relevant for safety, such as the safety interlocks, purge and HT input, are transferred independently of the bus communication by separate cables.
BCU 560, BCU 565 · Edition 02.16 12
Application > Examples of application
PZL PZH PZ
45
P
>750°
47 4858
DL
minDLPurge
PZL PDZ
DG DG
VAS
VAS
pu/2
DG DG DG
DG
46
1
ϑ
2
3
min
49 15 131450
DG
max
µC
FCU 500..F0
STM
M
VAS
BCU 560..F3
BCU 560..F3
VCG
VR..L
VCG
VR..L
1.1.7 ON/OFF rotary impulse control for burners up to 360kW
For processes which require a turndown of more than 10:1 and/or those which require heavy circulation of the furnace atmosphere to ensure a uniform tem-
M
perature, 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 system con-
trols the gas pressure on the burner 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.
The ignition and monitoring of the in-
dividual burners is ensured by burner
TE
control unit BCU560.
The centrally checked safety functions
such as pre-purge, tightness test, flow detector and pressure switch check (gas
min.
, gas
max.
, air
) are provided
min.
by the FCU500.
BCU 560, BCU 565 · Edition 02.16 13
Application > Examples of application
PZL PZH PZ
DG DG DG
min
49 15 131450
DG
max
µC
DG
1
ϑ
2
3
FCU 500..F1
STM
DL
minDLPurge
M
PZL PDZ
VAS
pu/2
45
P
57
16
>750°
TC
0°➔90°
53
90°➔0°
54 55
47 4858
VAS
M
VAS
BCU 560..F0
66
BCU 560..F0
66
VCG
VCG

1.1.8 Modulating burner control

For processes that do not require heavy circulation in the furnace, e.g. aluminium smelting furnaces.
This system is suitable for processes in
which infiltrated air may flow into the
M
furnace through switched off burners.
The capacity can be adjusted continu-
ously by activating the control element (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 monitoring.
The centrally checked safety functions
such as pre-purge, setting the valve to ignition position via a butterfly valve control system, tightness test, flow detec­tor and pressure switch check (gas gas
max.
, air
) are provided by the
min.
min.
,
FCU500.
DGDG
TE
BCU 560, BCU 565 · Edition 02.16 14
2 Certification
Certified to SIL and PL
For systems up to SIL 3 pursuant to EN 61508 and PL e pursu- ant to ISO 13849
EU certified pursuant to
– Gas Appliances Directive (2009/142/EC)
Meets the requirements of the
– Low Voltage Directive (2006/95/EC), – EMC Directive (2004/108/EC).
FM approved
Factory Mutual Research Class: 7400 Process Control Valves. Designed for applications pursuant to NFPA 85 and NFPA 86. www.approvalguide.com
Eurasian Customs Union
The products BCU 560 and BCU 565 meet the technical speci- fications of the Eurasian Customs Union.
BCU 560, BCU 565 · Edition 02.16 15

3 Function

3.1 Connection diagram

3.1.1 BCU560..F3 with ionization control in double- electrode operation
Alternative flame control, see page22 (Flame control).
Electrical connection, see page106 (Project planning infor­mation)
Explanation of symbols, see page126 (Legend)
Z
I
HT
P
0,6 × I
ϑ
A
p
u
PZL
GZL
2
P69
P70
P70
P72P71
P72P72
P73
N
1 2 3 4645 65 66 67 6849 50 51
5 6 9 11
61
c
24V
DC
c
230V
2AT
1210762
3,15AT
41 42
17 18 37 38
max. 1 A; 24
V
DC,
250 V AC
V3
88
µC
13 14 15
53 54
V2
V1
BCU 560..F3
0 V+24 V
NL1
BCU 560, BCU 565 · Edition 02.16 16
Function > Connection diagram
3.1.2 BCU560..F1
Alternative flame control, see page22 (Flame control). Detailed connection diagrams for actuators and frequency
converters, see from page78 (Capacity control) Electrical connection, see page106 (Project planning infor-
mation) Explanation of symbols, see page126 (Legend)
Z
I
ϑ
A
p
u
PZL
GZL
2
HT
P
P69
P70
P70
P72P71
P72P72
P73
1 2 3 4645 65 66 67 6849 50 51
5 6 9 11
61
c
24V
DC
c
230V
1210762
3,15AT
41 42
17 18 37 38
max. 1 A; 24
V
DC,
250 V AC
V3
88
µC
13 14 15
53 54 55 56
V2
V1
mA
52
0,6 × I
N

BCU 560..F1

(P40 = 2/3) => 51
0 V+24 V
NL1
BCU 560, BCU 565 · Edition 02.16 17
Function > Connection diagram
3.1.3 BCU560..F2
Alternative flame control, see page22 (Flame control). Detailed connection diagrams for actuators and frequency
converters, see from page78 (Capacity control) Electrical connection, see page106 (Project planning infor-
mation) Explanation of symbols, see page126 (Legend)
Z
I
HT
P
0,6 × I
ϑ
A
p
u
PZL
GZL
2
(P69 = 13)
P70P70
P72P71
P72P72
P73
N
1 2 3 4645 65 66 67 6849 50 51
52
5 6 9 11
61
c
230V
24V
DC
88
µC

BCU 560..F2

1210762
3,15AT
41 42
17 18 37 38
max. 1 A; 24 V DC, 250 V AC
c
V3
V2
V1
mA
0 V+24 V
NL1
AUTO
LO
COM
13 14 15
HI
53 54 55 56
BCU 560, BCU 565 · Edition 02.16 18
Function > Connection diagram
3.1.4 BCU565..F3 with ionization control in double- electrode operation
Alternative flame control, see page22 (Flame control) Electrical connection, see page106 (Project planning infor-
mation) Explanation of symbols, see page126 (Legend)
Z
I
ϑ
A
p
u
PZL
GZL
2
PZL
PZL
Air
min
HT
P
P70P70
P72P71
PDZ
PDZ
Air
P69
P72P72
P73
1 2 3
44
4645 4847 65 66 67 6849 50 51
5 6 9 11
62 61
c
24V
DC
88
7
c
2AT
1210
3,15AT
41 42
17 18 37 38
max. 1 A; 24 V DC, 250 V AC
V3
13 14 15
µC
53 54
V2
V1
52
0.6 × I
N
L1
BCU 565..F3
0 V+24 V
N
BCU 560, BCU 565 · Edition 02.16 19
Function > Connection diagram
3.1.5 BCU565..F1
Alternative flame control, see page22 (Flame control). Detailed connection diagrams for actuators and frequency
converters, see from page78 (Capacity control) Electrical connection, see page106 (Project planning infor-
mation) Explanation of symbols, see page126 (Legend)
Z
I
ϑ
A
p
u
PZL
GZL
2
PZL
PZL
Air
min
HT
P
P70P70
P72P71
PDZ
PDZ
Air
P69
P72P72
P73
1 2 3 4645 4847 65 66 67 6849 50 51
44
5 6 9 11
62 61
c
24V
DC
88
7
c
1210
3,15AT
41 42
17 18 37 38
max. 1 A; 24 V DC, 250 V AC
V3
13 14 15
µC
53 54 55 56
V2
V1
mA
52
0.6 × I
N
L1

BCU 565..F1

(P40 = 2/3) => 51
0 V+24 V
N
BCU 560, BCU 565 · Edition 02.16 20
Function > Connection diagram
3.1.6 BCU565..F2
Alternative flame control, see page22 (Flame control). Detailed connection diagrams for actuators and frequency
converters, see from page78 (Capacity control) Electrical connection, see page106 (Project planning infor-
mation) Explanation of symbols, see page126 (Legend)
Z
I
ϑ
A
p
u
PZL
GZL
2
PZL
PZL
Air
HT
0.6 × I
min
P
P70P70
P72P71
N
PDZ
PDZ
Air
(P69 = 13)
P72P72
P73
L1
1 2 3 4645 4847 65 66 67 6849 50 51
52
5 6 9 11
62 61
7
c
24V
DC
c
88
µC

BCU 565..F2

1210
3,15AT
AUTO
COM
41 42
max. 1 A; 24 V DC, 250 V AC
17 18 37 38
V3
13 14 15
LO
HI
53 54 55 56
V2
V1
mA
0 V+24 V
N
BCU 560, BCU 565 · Edition 02.16 21
Function > Connection diagram
1 2 3 4645 65 66 67 6849 50 51
41 42
5 6 9 11
1210762
61
Z
NL1
1 2 3 4645 65 66 67 6849 50 51
41 42
5 6 9 11
1210762
61
UVS
1 2 3
Z
NL1
1 2 3 4645 65 66 67 6849 50 51
41 42
5 6 9 11
1210762
61
ϑ
0 V
24 V
+–
0–20 mA
UVD1
1
2
4
3
5 6
Z
NL1

3.1.7 Flame control Ionization control in single-electrode operation

UVS control
UVD control
A voltage supply of 24 VDC is required to operate the UV sensor for continuous operation UVD1.
The 0 – 20mA current output can be used to display the flame
signal. The cable to the control room must be screened. The 0 – 20mA current output is not required for normal operation.
BCU 560, BCU 565 · Edition 02.16 22
Function

3.2 BCU 560 program sequence

Parameters 48 and 49 = 0: High/Low control during operation, cooling in standby
Example of application, see page8 (Two-stage-controlled burner)
Switch on BCU 560
▼
In the event of fault signal: reset
▼
00
P0
A0
H1
02
External actuation of the air valve for purging
External actuation of the air valve for cooling
Wait until the running time has elapsed (P42)
Safety interlocks
Start-up position/standby
▼
Flame simulation check
▼
▼
▼
Start-up with ϑ signal
▼
▼
Safety time 1 t
(P94) running,
SA1
ignition in process,
valves for 1st gas stage open.
▼
If no flame detected:
max. 3 start-up attempts (P07)
or fault lock-out
▼
03
Flame proving period 1 t
FS1
▼
running (P95)
In the event of flame failure:
fault lock-out
▼
04
Operation signalling contact closes,
valve for 2nd gas stage opens and
min. operating time tB starts to elapse (P61)
▼
In the event of flame failure:
restart or fault lock-out
▼
A4
External actuation of the air valve for capacity control
04
00
Controlled shut-down via ϑ signal
▼
If min. operating time tB has elapsed:
operation signalling contact opens,
gas valves close and
running time (P42) starts to elapse
BCU 560, BCU 565 · Edition 02.16 23
Function

3.3 BCU 565 program sequence

Switch on BCU 565
▼
In the event of fault signal: reset
▼
00
A0
The air actuator can be opened for cooling
00
H1
Wait until the running time has elapsed (air actuator
verification of air “no flow” state check
P1
A1
Pre-purge after safety shut-down running (P34)
Pre-ventilation time tVL running (P36),
A2
Safety interlocks
Start-up position/standby
▼
▼
Flame simulation check
▼
Start-up with ϑ signal
▼
in ignition position) (P42)
If P15 and P35 = 1 or 2:
▼
If P15 and P35 = 1 or 2:
air flow monitoring
▼
air actuator opens
▼
Safety time 1 t
running (P94),
SA1
ignition in process,
valves for 1st gas stage open.
▼
A3
A4
A4
A0
00
If no flame detected:
max. 3 start-up attempts (P07)
or fault lock-out
▼
Flame proving period 1 t
FS1
▼
running (P95)
In the event of flame failure:
fault lock-out
▼
Operation signalling contact closes,
valve for 2nd gas stage opens and
min. operating time tB starts to elapse (P61)
▼
In the event of flame failure:
restart or fault lock-out
Controlled shut-down via ϑ signal
▼
If min. operating time tB has elapsed:
operation signalling contact opens,
gas valves close and
running time (P42) starts to elapse
▼
Post-ventilation time tNL running (P39)
Air actuator is closed,
running time starts to elapse (P42)
BCU 560, BCU 565 · Edition 02.16 24

4 Air control

M
PZL PZH PZ
PZL PDZ
TE
M
FCU 500..F0
µC
P
DG DG DG
VAS
VAS
VCG
VCG
VR..L
VR..L
DG DG
DG
minDGmax
49 15 131450
45
47 4858
>750°
pu/2
DL
minDLPurge
BCU 5xx..F3
BCU 5xx..F3
ϑ
1
46
2
3
A central protective system such as the FCU500 takes over air control. It monitors the static air pressure as well as the air volume required for pre-purge, start-up and after the furnace has been shut down. The air actuators (BCU..F1 = actuators IC 20/40, BCU..F2 = RBW actuators, BCU..F3 = valve) are actuated for this purpose by the capacity control system of the BCU.
After being enabled by the protective system, the BCU can start the burners. The capacity is controlled during operation by an external temperature control system.
VAS
BCU 5xx..F3
49 15 131450
46
1
2
3
FCU 500
M
µC
P
>750°
DL
minDLPurge
PZL PDZ
DG DG
45
BCU 5xx..F3
BCU 560, BCU 565 · Edition 02.16 25
Air control
BCU 560..C0F1
µC
VAS VAG
TZI/TGI
V1
V2
V3
14 15
13
9 7
UVS
38371817
1 2 3
46
49
50
41
42
M
52 53 54 55 56
VAS 1
Process control (PCC)
ϑ
A
P
DI
FCU 500
SPS

4.1 Capacity control

4.1.1 BCU..F1/F2

system (FCU 500) starts the pre-purge time if there is adequate air flow. After the elapse of the pre-purge time, the control element moves to the ignition position. Once the protective system (terminal 46, safety interlocks) has issued the enable signal, the burner can be started by the start-up signal at terminal 1. The control element can be activated to control the burner’s capacity dependent on parameters 48 and 49.
Modulating control
Parameter 48 = 3 After the operating signal has been received from the burner
and after expiry of the delay time for the controller enable signal (parameter 44), the BCU issues the controller enable signal via the output at terminal 56. Access to the control ele­ment is thus transferred to an external temperature controller (3-point step). The temperature controller controls the burner capacity (air volume) on the basis of the required temperature. Depending on the wiring of the temperature controller, the actuator may be adjusted between maximum capacity and ignition capacity or minimum capacity.
Depending on parameter40, an actuator IC20, IC40, IC50 or an actuator with an RBW interface can be actuated via the outputs for capacity control. Detailed information about parameter 40, see from page78 (Capacity control).
The BCU..F1/F2 activates a control element via the outputs for capacity control (terminals 53 to56) for purging, cooling or starting the burner. This control element moves to the required position for the relevant operating situation.
As soon as there is a purge signal at terminal 50 of BCU..F1/ F2, the control element is activated by the outputs for capacity
Staged control
P48 = 0, 1 or 2 Depending on parameters 48 and 49, the control element may
be activated either by the program or externally via the input at terminal 2, see also from page87 (Air actuator control).
control to approach the position for pre-purge. The protective
BCU 560, BCU 565 · Edition 02.16 26
Air control > Capacity control
BCU 560..C0F3
µC
VAS VA G
TZI/TGI
VR..L
V1 V2
14
13
9 7
10
UVS
38371817
1 2 3
FCU 500
Process control (PCC)
46
49
50
P
HT
ϑ
41
42
A
SPS

4.1.2 BCU..F3

The BCU..F3 activates an air valve for purging, cooling or start- ing the burner. The required air capacity is released by the air valve.
As soon as there is a purge signal at terminal 50 of BCU..F3, the air valve is activated by the output at terminal 10. The protective system (FCU 500) starts the pre-purge time if there is adequate air flow. After the elapse of the pre-purge time, the air valve closes for ignition. Once the protective system (terminal 46, safety interlocks) has issued the enable signal, the burner can be started by the start-up signal at terminal 1. The gas valves for the 1st stage are opened and the burner is ignited (on the BCU..C1 after a successful valve check). After the operating
signal has been received from the burner, the gas valve for the 2ndstage opens.
Staged control
P48 = 0, 1 or 2 Depending on parameters 48 and 49, the control element may
be activated either by the program or externally via the input at terminal 2, see also from page87 (Air actuator control).
BCU 560, BCU 565 · Edition 02.16 27

5 menox® low NOx mode

▼
menox® low NOx mode leads to a drastic reduction in thermal NOx formation in ON/OFF-controlled high-velocity burners.

5.1 System structure and function

The system consists of a burner BIC..M with system compo- nents tailored to the application. The system components make it possible to operate the burner in two operating modes: conventional flame mode in low furnace temperatures and menox® low NOx mode with flameless combustion at higher furnace temperatures.
Process Control (PCC)
STM
AKT
VAD
M
VAS..L
BCU 565..D2
PZL
VMV
TZI/
TGI
BIC..M
The gas and air for flame mode and low NO
mode are sup-
x
plied via the same connections. The gas pressure upstream
of the burner is adjusted using a pressure regulator (e.g. VAD). The gas volume is set using a fine-adjusting valve (e.g. VMV). The air volume for the operating modes is set by adjusting
the butterfly valve (e.g. BVH). The air pressure is monitored
on each burner by a pressure switch to check the functioning
of the butterfly valve. In addition, air/gas ratio monitoring
for the zone or the furnace is required since the air pres-
sure switch is not sufficient for use as a low air pressure
protection device.
The menox
®
burner BIC..M has a special mixing unit whose geometric design ensures reliable ignition and a stable flame while also making sure that the combustion process is trans­ferred to the furnace chamber for menox® mode.
In menox
®
mode, the inflammable gas/air mixture must be prevented from igniting prematurely in the ceramic combustion chamber each time the burner is switched on. The flow velocity at the burner nozzle must be adequately high to prevent the danger of flashback into the combustion chamber. Burners BIC..M are tailored to the appropriate capacity and combined with tapered ceramic tubes (TSC..B).
IC 40 + BVH
DG
A burner BIC..M in conjunction with a burner control unit BCU..D2 is required for safe burner operation in menox® low NOx mode.
BCU 560, BCU 565 · Edition 02.16 28
menox® low NOx mode > System structure and function
850 1050 1250120011501100900 1000950
0
100
200
300
400
Furnace temperature [°C]
NO
x
[mg/m
3
, ref. 5% O
2
]
Flame mode
Natural gas, air preheating to 450°C
Flame mode
In order to heat up the furnace, the burner operates in flame mode.
The ignitable gas/air mixture is ignited using an electrical ignition spark and combusts inside and outside of the ce- ramic burner tube. The presence of the flame is monitored in compliance with EN746-2.
®
menox
mode
As soon as the combustion chamber temperature is ≥ 850°C, the burner control unit BCU..D2 can switch to menox® mode.
considerably larger and the reaction density considerably lower. This prevents the occurrence of peak temperatures which are responsible for high NOx values. Emissions of NOx are drastically reduced.
In menox® mode, NOx values can be reduced to below
150mg/m³ (reference value of 5% O2) even at a furnace tem-
perature of 1200°C and hot air at 450°C– without expensive additional piping. The high output pulse frequency and rotary impulse control ensure temperature uniformity which is of great advantage.
For further information on burner BIC..M, see www.docuthek.com
Gas and air are supplied through the same connections as in flame mode. No ignition takes place in the burner tube. The combustion process is relocated to the combustion chamber. The oxidation reactions take place without a visible flame. Compared to traditional flame mode, the reaction zone is
BCU 560, BCU 565 · Edition 02.16 29
menox® low NOx mode
38371817
1 2 3
46
50
41
44
42
ϑ
A
P

5.2 BCU..D2

The BCU coordinates the signals for starting the burner and the fail-safe monitoring of the burner in flame mode. In menox® mode, the BCU switches off the ignition device and flame control. The furnace chamber temperature must be monitored by a safety temperature monitor (STM) for menox® mode. This function must satisfy the requirements of a protective system pursuant to EN746-2.
Parameter 06 must be set to 5 to switch to menox® low NOx mode. The BCU..D2 must signal via terminal 49 that the required temperature for high temperature operation has been reached. A higher switching point of 850°C is required for menox® mode. menox® mode is enabled via the input at terminal 44: depending on parameter 64, the system is either switched over immediately or the next time the burner starts with the parameters of menox® pre-ventilation time, burner application and settings for the control element coordinated for menox® mode.
Parameter settings for switching between flame mode and menox® mode, see pages 63 (Burner application), 95 (menox pre-ventilation time tVLM) and 95 (Switchover to menox® operating mode).
Process control (PCC)
FCU 500
HT
BCU 565..C0F1
µC
49
SPS
44
If there is no signal at terminal 44, the system switches from menox® mode to flame mode.
If the enable signal for High temperature mode (HT mode) drops out as the furnace temperature falls, the BCU automati­cally switches from menox® mode to flame mode. To avoid a pressure surge in the gas supply due to several burners being switched off at the same time, it is recommended that the furnace control unit switches the burners to flame mode again zone by zone, for example.
Hot air compensation and ratio control are not the respon­sibility of the BCU. These functions must satisfy the require-
ments of a protective system pursuant to EN 746-2 and be implemented externally.
BCU 560, BCU 565 · Edition 02.16 30
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