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Burner control unit PFU 780
Technical Information · GB
6 Edition 02.12
• For pilot and main burners of unlimited capacity in thermoprocessing
equipment pursuant to EN 746-2
• Plug-in function unit for mounting in 19" module subracks
• Separate flame control for pilot burner and main burner by UV,
ionisation or a further option of using the furnace chamber temperature
• Display of the program status, unit parameters and flame signal;
Manual mode for burner adjustment and for diagnostic purposes
• Visualisation and adaptation to the specific application via the PC
programming and diagnostic software BCSoft to simplify logistics
management
• Air valve control relieves the furnace control
• Certified for systems up to SIL 3 and compliant with PL e
AGA
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Summary of Contents for Krom Schroder PFU 780
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Page 1: Burner Control Unit Pfu 780
Burner control unit PFU 780 Technical Information · GB 6 Edition 02.12 • For pilot and main burners of unlimited capacity in thermoprocessing equipment pursuant to EN 746-2 • Plug-in function unit for mounting in 19" module subracks • Separate flame control for pilot burner and main burner by UV, ionisation or a further option of using the furnace chamber temperature • Display of the program status, unit parameters and flame signal;... -
Page 2: Table Of Contents
3.1.2 PFU 780..K2........ - Page 3 8.10 Field bus interface PFA 700..... 59 8.11 Impulse system MPT 700..... . . 60 ▼ = To be continued PFU 780 · Edition 02.12...
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Page 4: Application
If the local requirements on the burner control units change, The PFU 780 can be used for industrial burners of unlimited the PC software BCSoft can be adjusted to the unit parameters capacity which are ignited by pilot burners. Pilot and main of the application by using the optical interface. - Page 5 Application Bogie hearth forging furnace Intermittent shuttle kiln Walking beam furnace in the metallurgical industry in the ceramics industry with overhead firing PFU 780 · Edition 02.12...
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Page 6: Examples Of Application
A UV sensor monitors the flame signal from pilot and main burners. UV sensor UVD 1 is used for continuous operation, UV sensor UVS for intermittent operation. 02–04 06–08 02–04 06–08 VR..L PFU 780 · Edition 02.12... -
Page 7: Stage-Controlled Main Burner With Permanent Pilot Burner
The main burner can be started with reduced capacity after the operating signal from the pilot burner has been detected. Pilot and main burners can be operated simultaneously. Both are ionisation-controlled independently. PFU 780 µC 02–04 06–08 06–08 VR..R PFU 780 · Edition 02.12... -
Page 8: Modulating-Controlled Burner
The control system controls the burner capacity via the butterfly valve for PFU 780 air BV after the operating state has been signalled. Pilot and main burners can be µC operated simultaneously. BV+IC PFU 780 · Edition 02.12... -
Page 9: Pfu 780..D
Application > Examples of application 1 .1 .4 PFU 780 . .D: High temperature equipment The flame is controlled indirectly on the basis of the temperature. During the start-up process, as long as the wall temperature is below auto ignition tem- perature the flame must be controlled by conventional methods. -
Page 10: Certification
EN 298:2004-01, Meets the requirements of the – Low Voltage Directive (2006/95/EC), – EMC Directive (2004/108/EC). PFU . .T is FM approved Factory Mutual Research Class: 1997. Suitable for applications pursuant to NFPA 86. www.approvalguide.com PFU 780 · Edition 02.12... -
Page 11: Function
PFU 780 L1 (L1) 3 .1 Connection diagram For cable selection and wiring, see page 49 (Project plan- ning information). 3 .1 .1 PFU 780 For the explanation of symbols, see page 66 (Legend). N (L2) 230 V ϑ1 µC 24 V ϑ2... -
Page 12: Pfu 780
Function > Connection diagram 3 .1 .2 PFU 780 . .K2 As a replacement unit for burner control unit PFU 798. PFU 780..K2 L1 (L1) For the explanation of symbols, see page 66 (Legend). N (L2) 230 V ϑ1 µC 24 V ϑ2... -
Page 13: Pfu 780 Program Sequence
(display A1 ). Wait until start-up signal ϑ1 has been applied, the waiting time t PFU 780 opens valve V1 and ignites the has elapsed burner. The ignition time t is constant. If a flame is detected during the safety time... - Page 14 Function > PFU 780 program sequence The PFU coordinates the correct program run for the pilot and main burners. The The air valve can be set to open Flame proving period t main burner can be started via the sig-...
- Page 15 Function > PFU 780 program sequence Behaviour of the pilot burner in the event of flame failure during operation Flame proving period The air valve can be set to open If the flame fails during operation, either...
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Page 16: Program Status And Fault Messages
Flame failure during flame proving period, main burner Operation, main burner Flame failure during operation, main burner Purge Air valve High temperature operation** Faulty remote reset Supply voltage too low Faulty parameterisation Short-circuit on a valve output ▼ PFU 780 · Edition 02.12... - Page 17 Short-circuit on ignition or valve output Safety interlock failure Permanent reset Time between two start-ups is too short * In Manual mode, two dots will blink on the display in program status 01 – 08 . ** Optionally available. PFU 780 · Edition 02.12...
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Page 18: Parameters
0; 2; 3 Air valve can be activated externally on start-up 0; 1 Air valve closed/can be activated in the event of malfunction 0; 1 High temperature operation ** 2; 3 ▼ PFU 780 · Edition 02.12... -
Page 19: Scanning The Parameters
Reset/Information button (for 2 s). In the event of a fault, the PFU halts the program run, the display blinks and it then displays the cause of the fault in coded form. PFU 780 · Edition 02.12... -
Page 20: Flame Control
In parameter 03, it is now shown which program position the unit was in when the fault was detected (waiting time 01 or standby 00 ). Result: A flame simulation was detected during the waiting time or standby. PFU 780 · Edition 02.12... -
Page 21: High Temperature Operation With Pfu
For this purpose, we recommend a safety temperature monitor with twin thermocouple (DIN 3440). Sensor discontinuity, sensor short-circuit, failure of a component or mains failure must set the installation to a safe state. PFU 780 · Edition 02.12... - Page 22 UV control with UVS). When High temperature mode is ended, the PFU switches off ▼ the burner and restarts with flame simulation check (recom- mended in the case of UV control with UVS). PFU 780 · Edition 02.12...
- Page 23 2c–4c When High temperature mode is ended, the burner remains in operation and the PFU performs flame control again 6a–6e (recommended in the case of ionisation control or UV control 2e–4e with UVD). PFU 780 · Edition 02.12...
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Page 24: Uvs Check
It must be ensured in this case that the program sequence started matches the application. This parameter may be set in this way only if the burner can restart as intended in all operating phases. PFU 780 · Edition 02.12... -
Page 25: Pilot And Main Burner Monitoring
Parameters 4 .3 Pilot and main burner monitoring Intermittent pilot burner Burner control unit PFU 780 for pilot and main burner combi- 02–04 06–08 02–04 06–08 nation of unlimited capacity. Pilot burner: single-stage-controlled. Main burner: modulating or stage-controlled. The burner control unit PFU 780 has separate start-up signal... -
Page 26: Permanent Pilot Burner
Start-up as in the illustration “Permanent pilot burner” with the difference being that the start-up signal for pilot and main burners is applied synchronously and that immediately after the flame proving period t , the main burner is started. PFU 780 VR..R PFU 780 · Edition 02.12... -
Page 27: Interrupted Pilot Burner
In this setting, the flame signal can be connected to terminals 18a or 26a. 2c–4c The pilot burner is switched off after the main burner safety time t has elapsed. 6a–6e 2e–4e PFU 780 VR..R PFU 780 · Edition 02.12... -
Page 28: Behaviour In Start-Up Position/Standby
This allows fast start-up of the burner since there is no waiting time t The burner must have been switched off for at least 4 s before start-up in order for the flame simulation check to be con- ducted correctly. PFU 780 · Edition 02.12... -
Page 29: Minimum Burner Pause Time T
After the pause time, the burner is started if the start-up signal (ϑ) is applied. The minimum burner pause time t serves to adapt the pro- gram sequence to the requirements of the application. PFU 780 · Edition 02.12... -
Page 30: Behaviour During Start-Up
4 .5 .1 Safety time on start-up t Pilot burner Parameter 22 2c–4c 6a–6e 2e–4e 2c–4c 2e–4e Safety time on start-up t for the main burner. Safety time on start-up t for the pilot burner. PFU 780 · Edition 02.12... -
Page 31: Flame Proving Period T
Main burner 6a–6e 2e–4e Parameter 25 2c–4c 6a–6e 2e–4e Programmable time between 0 and 25 s. This time elapses before the PFU starts the next program step so as to give the flame time to stabilise. PFU 780 · Edition 02.12... -
Page 32: Burner Start-Up Attempts
1 start-up attempt Parameter 10 = 1 2c–4c 2e–4e If no flame forms during start-up, a fault lock-out is performed after expiry of time t . The display blinks and shows the cause of the fault. PFU 780 · Edition 02.12... - Page 33 2c–4c 6a–6e 2e–4e If no flame forms during the start-up of the main burner, a fault lock-out is performed after expiry of time t . The display blinks and shows the cause of the fault. PFU 780 · Edition 02.12...
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Page 34: Behaviour During Operation
The PFU cannot be reset by mains failure. The fault signalling contact does, however, open as soon as the mains voltage fails. See also parameter 32, Behaviour of the air valve in the event of a fault lock-out. ▼ PFU 780 · Edition 02.12... - Page 35 The precondition for a restart is that activation of the restart allows the burner to restart as intended (in all operating phases). In this case, it must be ensured that the program sequence started by the PFU matches the application. PFU 780 · Edition 02.12...
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Page 36: Fault Lock-Out Or Restart, Main Burner
. This in- volves disconnecting the power from the gas valves and the ignition transformer. The fault signalling contact closes, the display blinks and shows the current program status (see table “Program status and fault messages”). PFU 780 · Edition 02.12... - Page 37 The precondition for a restart is that activation of the restart allows the burner to restart as intended (in all operating phases). In this case, it must be ensured that the program sequence started by the PFU matches the application. PFU 780 · Edition 02.12...
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Page 38: Air Valve Control Pfu
– Switching of the burner between low and high burner out- put during operation via the air valve PFU 780..K2: For purging, the safety interlock (limits) must – To start up the burner as intended, external activation of activate input 26e and input 30e of the PFU. -
Page 39: Air Valve Opens In The Case Of External Activation (Not During Start-Up)
External control allows switchover between low fire and high 2e–4e fire during operation. The air valve can be activated externally via input 10a for cool- ing the burner in the start-up position/standby. PFU 780 VR..R PFU 780 · Edition 02.12... -
Page 40: Air Valve Opens In The Case Of External Activation (Even During Start-Up)
These settings may be selected only if the burner can start with full air capacity. The air valve can be activated externally via input 10a for cool- 2c–4c ing the burner in the start-up position/standby. 6a–6e 2e–4e PFU 780..L VAS 1 PFU 780 · Edition 02.12... -
Page 41: Air Valve Opens With Valve V2
Single-stage-controlled main burner is switched ON/OFF via the ϑ input. The air valve can be activated externally via input 10a for cool- 2c–4c ing the burner in the start-up position/standby. 6a–6e 2e–4e PFU 780..L VR..R PFU 780 · Edition 02.12... -
Page 42: Air Valve Opens With Operating Signal
Two-stage-controlled main burner is switched ON/OFF via the ϑ input. The air valve can be activated externally via input 10a for cool- 2c–4c ing the burner in the start-up position/standby. 6a–6e 2e–4e PFU 780..L VR..R PFU 780 · Edition 02.12... -
Page 43: Low Fire Over Run Time T Kn After A Normal Shut-Down
On/Off control. It must be ensured that VG..N no excess gas occurs. The low fire over run time has an effect on the behaviour of VR..R the main burner only. Background: The pilot burner is only used in single-stage operation. PFU 780 · Edition 02.12... -
Page 44: Behaviour Of The Air Valve In The Event Of A Fault Lock-Out
The air valve is closed in the event of a fault. It cannot be activated externally via terminal 10a. Parameter 32 = 1: The air valve can be activated externally via input 10a even during a fault, e.g. for cooling. PFU 780 · Edition 02.12... -
Page 45: Manual Operation
On units with air valve control, the air valve can be opened and closed repeatedly by pressing the button during operation. Manual mode can be terminated by switching off the PFU (On/Off button). PFU 780 · Edition 02.12... -
Page 46: Password
The password can be changed using BCSoft. Note the effect of parameter settings on the safe functioning of your system. The password set at the factory can be found in the delivery note supplied. PFU 780 · Edition 02.12... -
Page 47: Selection
5 Selection 5 .1 Calculating the safety time t PFU 780 · Edition 02.12... -
Page 48: Selection Table
110 – 120 V~, -15/+10 %, 50/60 Hz Digital input Order example to interrupt fl ame control PFU 780LT Preparation for UV sensor for continuous operation UVD 1 Compatible with PFU 798 * If “none”, this specifi cation is omitted. PFU 780 · Edition 02.12... -
Page 49: Project Planning Information
. Cable length: max. 100 m. Avoid external electrical interference. Install as far as possible from mains and igni- tion cables and interference from electro-magnetic sources. If possible, do not lay in a metal conduit. Several ionisation cables can be routed together. PFU 780 · Edition 02.12... -
Page 50: Minimum Combustion Time
The minimum combustion time for the pilot burner is limited to the safety time on start-up (t Background: The pilot burner is only used in single-stage operation. PFU 780 · Edition 02.12... -
Page 51: Reset
Reset/Information button on the unit. Note the requirements of the Standards. For exceptions, see The burner malfunction must be remedied. The malfunction Standards. can not be remedied by changing the method of activation. PFU 780 · Edition 02.12... -
Page 52: Fault Message
If the unit is switched off, an immediate program abort with switch-off of all outputs occurs (even during the safety time). When the unit is switched on, the program run is restarted in standby. PFU 780 · Edition 02.12... -
Page 53: Furnace Control
PROFIBUS units, to switch off the unit without causing BUS errors. Disconnection for electrical maintenance work is to be implemented with an external switch per unit or group only, in accordance with Standard “EN 50156”. PFU 780 · Edition 02.12... -
Page 54: Flame Control
This can be programmed using parameter 35. For further information, see brochure UVS. The burner control unit PFU..U is prepared for UV sensor UVD 1. This enables continuous operation. For further information, see Technical Information Bulletin UVD. PFU 780 · Edition 02.12... -
Page 55: Accessories
The current software can be downloaded from our Internet site signalétique ne sont plus valables dans leur intégralité. Veuillez vous at http://www.docuthek.com. To do so, you need to register référer directement aux paramètres actualisés. in the DOCUTHEK. PFU 780 · Edition 02.12... -
Page 56: Radio Interference Suppressed Electrode Adapters
PROFIBUS DP with D-Sub socket. BGT SA-9: slot 1 for PFA 700, slots 2-10 for PFU 760, BGT SA-8: slot 1 for PFA 710, slots 2-9 for PFU 780 Order no. BGT SA-9U/1 DP700: 84402291... -
Page 57: Power Supply Pfp 700
Operating status display on the front plate. PFP switches off in the event of an output overload. Output voltage 24 V, output rating 14 VA. Order No. 84366510 PFP 700 230 V 115 V 24 V= 8ace 600 mA 12ace PFU 780 · Edition 02.12... -
Page 58: Relay Module Pfr 704
Contact rating of floating outputs: max. 2 A, 264 V (not fused internally). Order No. 84373510 PFR 704 230 V~ 115 V~ 24 V=/~ 230 V~ 115 V~ 24 V=/~ 230 V~ 115 V~ 24 V=/~ 230 V~ 115 V~ 24 V=/~ PFU 780 · Edition 02.12... -
Page 59: Field Bus Interface Pfa 700
9. PFU µC 1. PFU 9. PFU RxD/TxD-P RxD/TxD-N 1. PFU DGND 9. PFU 24 V 1. PFU 24 V 9. PFU 1. PFU 24 V 5. PFU 24 V 6. PFU 9. PFU 24 V PFU 780 · Edition 02.12... -
Page 60: Impulse System Mpt 700
Accessories 8 .11 Impulse system MPT 700 With 11 outputs for activation of burner control units PFU 780. The furnace atmosphere is circulated thanks to intermittent operation, and thereby constant temperature distribution and shorter heating-up periods for all gas-fired heat treatment furnaces are ensured. -
Page 61: Technical Data
0 – 20 V 0 – 40 V Frequency 50/60 Hz 50/60 Hz Rated value 24 V DC Signal “1” 24 V, ±10% Signal “0” < 1 V Inherent current: Signal “1” typ. 5 mA PFU 780 · Edition 02.12... - Page 62 BGT, the front corresponds to IP 20. Input/Output safety circuit: All the inputs and outputs marked “ ” (see connection dia- grams) may be used for safety tasks. Weight: approx. 650 g (23 oz.). PFU 780 · Edition 02.12...
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Page 63: Safety-Specific Characteristic Values
MTTF Safe failure fraction SFF 99.2% The specified values apply for the combination with ionization electrode (sensor) and PFU 780 (logic). Relationship between the Performance Level (PL) and the Safety Integrity Level (SIL) – Pursuant to EN ISO 13849-1:2006, Table 4, the PFU can be used up to PL e. -
Page 64: Operating Controls
B: Reset/Information button to reset the system after a fault or to scan parameters on the display C: Mains switch D: Optical interface E: Type label 3 HE = 133.4 (5.3“) 8 TE = 40.6 (1.6“) PFU 780 · Edition 02.12... -
Page 65: Maintenance Cycles
10 Maintenance cycles Burner control unit PFU requires little servicing. PFU 780 · Edition 02.12... -
Page 66: Legend
Safety time on start-up 3 s, 5 s or 10 s Safety time during operation < 1 s or < 2 s Ignition time 2 s, 3 s or 6 s Flame simulation delay time 25 s Flame proving period 0 – 25 s PFU 780 · Edition 02.12... -
Page 67: Glossary
The duration of the ignition time is either 2, 3 or 7 seconds (depending on safety time t selected). If the flame fails during operation, the valve outputs are dis- connected within the safety time t PFU 780 · Edition 02.12... -
Page 68: Flame Signal
It remains open until the burner is switched ϑ2 – to control the burner capacity in ON/OFF mode and in off again by a normal shut-down or fault lock-out. High/Low mode when using a pneumatic air/gas ratio control system. PFU 780 · Edition 02.12... -
Page 69: Diagnostic Coverage Dc
EN 13611/A2:2011 12 .16 Probability of dangerous failure PFH Value describing the likelihood of dangerous failure per hour of a component for high demand mode or continuous mode. Unit: 1/h from EN 13611/A2:2011 PFU 780 · Edition 02.12... -
Page 70: Feedback
Strotheweg 1 · 49504 Lotte (Büren) Germany T +49 541 1214-0 We reserve the right to make technical modifications F +49 541 1214-370 in the interests of progress. info@kromschroeder.com Copyright © 2014 Elster GmbH www.kromschroeder.com All rights reserved. PFU 780 · Edition 02.12...
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