BURKERT 20073326 (Type 8647 AirLINE SP) is a modular electropneumatic automation system engineered for seamless mechanical and electrical integration with the Siemens SIMATIC ET 200SP and SIMATIC ET 200SP HA distributed I/O systems. Built in a Revision 2 (REV.2) hardware architecture with an 11 mm width per station, this fully assembled 20-bank valve terminal houses 20 Type 6524 double solenoid valves. Each valve station provides two independently actuated 3/2-way normally closed valves (Circuit Function C C), delivering a total of 40 discrete pneumatic control channels in a high-density footprint.

Primary air supply and common exhaust lines interface through G 1/4 female threaded ports on the connection units, while working connections emerge as bottom-oriented D6 push-in couplings. Pneumatic stability across the 40 valve functions is sustained by an integrated PSU-M intermediate feed unit. The assembly incorporates check valves within exhaust ports 3 (R) and 5 (S) to eliminate back-pressure switching interference, alongside integrated P-channel HotSwap shut-off seats that permit single-valve replacement while the remaining valve block remains fully pressurized. BURKERT 20073326 carries ATEX and IECEx explosion-proof certification for Category 3G equipment (Zone 2, Ex ec IIC T4 Gc) and operates across 2.5 to 10.0 bar within an ambient temperature range of 0 °C to +55 °C.

System Architecture and Module Configuration

Type 8647 combines electrical bus communications and pneumatic power amplification on a common DIN rail. The 20073326 configuration is assembled from four interconnected functional modules:

1. Pneumatic Connection Units (PSU): Form the structural ends and intermediate supply blocks. A left connection unit (PSU-L) establishes the physical and electrical interface to the adjacent Siemens ET 200SP BaseUnit, an intermediate feed unit (PSU-M) injects supplemental air after 16 valve functions, and a right connection unit (PSU-R) terminates the fluidic bus.
2. Electronic Base Modules (PQ Modules): Latch directly onto the backplane bus, receiving output process commands and relaying diagnostic telemetry. Each electronic module incorporates status LEDs, driver electronics with short-circuit protection, and a graphics LC display showing valve switching states, channel errors, and maintenance counters.
3. Pneumatic Base Modules: Structural polymer manifolds featuring internal P, R, and S channels, integrated check valves, P-shutoff valves for live swapping, and bottom-facing push-in D6 tubing couplers.
4. Pilot Solenoid Valves: 20 Type 6524 2x3/2-way flipper-amplified seat valves fastened via M2 screws.

Revision 2 (REV.2) Design Features

BURKERT 20073326 incorporates REV.2 engineering improvements across all pneumatic sub-assemblies:

• Standardized Flange Pattern: Single valves and 2x3/2-way double valves utilize a unified FM20 pneumatic flange interface.
• Wavy Channel Arrangement: Working connections on the pneumatic base module are organized in a wave pattern rather than parallel rows, facilitating push-in hose handling.
• Blue Hose Release Rings: Quick-connect push-in fittings feature blue release collars to distinguish REV.2 hardware from REV.1 (black rings).
• Reduced Flow Penalty: Internal flow channel optimization limits flow reduction from integrated HotSwap P-shutoff to approximately 20%, compared to up to 50% in REV.1.

Technical Specifications

Feature	Parameter Specification
Product Identifier	BURKERT Type 8647 AirLINE SP (Article 20073326)
Hardware Generation	Revision 2 (REV.2)
Station Configuration	20 valve slots, 11 mm width per station (20-bank)
Integrated Valve Function	20x (2x 3/2-way) Circuit Function C C (normally closed)
Total Controlled Channels	40 independent pneumatic working outputs
Operating Pressure Range	2.5 bar to 10.0 bar (gauge pressure)
Flow Rate ($Q_{\text{Nn}}$ air)	300 l/min (measured at +20 °C, 6 bar inlet, 1 bar $\Delta p$; ~20% reduction with P-shutoff)
Nominal Operating Voltage	24 V DC (±10%), max residual ripple 2.4 Vss, SELV/PELV
Power Consumption per Valve	2x 0.8 W (with electronic power reduction)
Current Draw per Valve	40 mA inrush; 28 mA holding current after 120 ms
Protection Class	III according to DIN EN 61140, VDE 0140
Ingress Protection	IP20 according to EN 60529 (IP65 in closed control cabinet)
Operating Medium	Lubricated or non-lubricated dry compressed air, neutral gases (5 µm filtration)
Compressed Air Quality	ISO 8573-1:2010, Class 7.4.4
Medium Temperature	0 °C to +50 °C
Ambient Temperature	0 °C to +55 °C (storage: -20 °C to +60 °C)
Relative Humidity	75% average, 85% peak, non-condensing
Supply Port Connections (1, 3, 5)	G 1/4 female thread
Auxiliary Pilot / Exhaust Port (X)	M5 thread
Working Connections (2, 4)	D6 push-in tube coupling, bottom module orientation
Intermediate Feed Modules	1 PCE (PSU-M G 1/4)
HotSwap Functionality	Integrated mechanical P-shutoff valve per slot
Exhaust Check Valves	Integrated non-return valves in channels 3 (R) and 5 (S)
Explosion Protection	ATEX: BVS 18 ATEX E 078 X; IECEx: IECEx BVS 18.0068 X; II 3 G Ex ec IIC T4 Gc
Control Cabinet Requirement	Enclosure with minimum IP54 ingress protection

Pneumatic Ports and Piping Installation

Air supply and exhaust piping connect directly to the PSU connection blocks. The 20073326 terminal utilizes G 1/4 ports for main supply pressure 1 (P) and exhaust deaeration channels 3 (R) and 5 (S).

Port Identification	Marking	Fluidic Function	Thread / Connector Size
1	P / 1	Compressed air supply	G 1/4 female
2	X	Auxiliary pilot air / Pilot exhaust	M5 female
3	R / 3, S / 5	Common system exhaust	G 1/4 female
Working Outputs	2 (A), 4 (B)	Actuator working lines	Push-in D6 mm (bottom)

Exhaust Air Management

To prevent back-pressure accumulation and unintended valve switching, exhaust lines must be routed through silencers of adequate volume or ducted outside the cabinet using unrestricted tubing cross-sections. Do not plug exhaust ports 3, 5, or pilot exhaust X.

Intermediate Pneumatic Supply Rules

When deploying Type 6524 2x3/2-way double valves, an intermediate supply module (PSU-M) is required after every 16 valve functions (8 double valve slots) to avoid pressure drop during simultaneous actuations. Because BURKERT 20073326 houses 20 double valves (40 valve functions), 1 PCE intermediate feed unit (PSU-M) is factory-configured into the valve block array.

Working Connection Assignment

Each Type 6524 double valve contains two independently actuated 3/2-way valves corresponding to two separate working ports on the pneumatic base module:

• Lower Output Port 4 (B): Controlled by the primary electrical valve channel.
• Upper Output Port 2 (A): Controlled by the secondary electrical valve channel.

Tightening Torques for Pneumatic Ports

Port Size	Function	Recommended Torque	Maximum Torque
G 1/4	P (Supply), R/S (Exhaust)	4.0 Nm to 7.0 Nm	20.0 Nm
M5	X (Pilot exhaust / Aux air)	1.0 Nm to 1.2 Nm	3.0 Nm
M7	AirLINE Quick Push-in fittings	1.75 Nm to 2.25 Nm	4.0 Nm
M2	Type 6524 double valve fastening screws	0.15 Nm to 0.20 Nm	0.25 Nm

Integrated Type 6524 Pilot Solenoid Valves

Each valve slot on the 20073326 terminal is equipped with a Type 6524 2x3/2-way pilot valve. The pilot stages consist of Type 6144 flipper solenoid actuators directing air to pneumatic poppet seat amplifiers. This design delivers rapid cycle response and high holding force at a static holding power of only 0.8 W per coil.

• Circuit Function C: 3/2-way normally closed valve. De-energized state shuts port 1 (P) and vents actuator port 2 (A) or 4 (B) through exhaust port 3/5.
• Switching Response: Opening time is 12 ms; closing time is 20 ms (tested according to ISO 12238).
• Manual Override: Equipped as standard with a manual actuation mechanism. Press with a flat-blade screwdriver for momentary key function, or press and rotate clockwise for detented locking mode. Overrides must remain in neutral position during automated bus operation.

Control System Integration with Siemens SIMATIC

Type 8647 docks directly to the backplane bus of Siemens SIMATIC ET 200SP or ET 200SP HA modular peripheral systems without external intermediate wiring. Electrical load voltage (24 V DC) and backplane communication are established automatically as modules click together along the DIN rail.

Configuration Options in Siemens Engineering Tools

• SIMATIC TIA Portal: Integrated natively via Hardware Support Package HSP0225 (from TIA Portal V14 SP1) or GSDML file. AirLINE SP modules appear under Other field devices -> PROFINET IO -> I/O -> Pneumatics (Burkert).
• SIMATIC STEP 7 Classic: Configured via Hardware Support Package HSP2105 (from STEP 7 V5.5 SP4) or GSD file.
• SIMATIC PCS 7: Fully integrated via Hardware Update Package HUP (from PCS7 V9.0 SP2). In PCS7 V9.1 or higher, combined use with ET 200SP HA uses HSP0293 for BaseUnit configuration.
• Universal Fieldbus Master: Compatible with any PROFINET IO or PROFIBUS DP master via standard GSDML / GSD device description files.

Hardware Constraints and Power Provisioning

Power Bus Separation

A light-colored Siemens BaseUnit (BU...D or BU...D/T) must be installed immediately to the left of the valve block to feed a separate 24 V DC load voltage group. This arrangement is mandatory when operating in ET 200SP HA stations to prevent backplane voltage drop.

• SIMATIC ET 200SP: Up to 64 total I/O modules and valve blocks per station (maximum width 975 mm). Additional Siemens I/O modules can be mounted to the right of the valve block provided a new light BaseUnit is inserted.
• SIMATIC ET 200SP HA: Limited to one valve block per station (maximum station width 1,240 mm). The valve block must reside at the right-hand end of the HA station; no standard Siemens I/O modules may be placed to the right.

Channel Diagnostics and Telemetry

Each electronic base module monitors individual channel electrical integrity and backplane communication:

• Wire Break and Short Circuit: Detected per channel when the channel is activated. Diagnostic alarms trigger red flashing DIAG LEDs and transmit diagnostic numbers 0x02F3 (Wire break) or 0x02F4 (Short circuit) to the PLC.
• Undervoltage Detection: If supply drops below 21.6 V DC (24 V -10%), the PWR OK LED extinguishes and code 0x11 (No supply voltage) is generated. Valves switch off into their safe home position.
• Dual Switching Cycle Counters: Every channel maintains independent remanent counters for both the pilot solenoid valve and the connected field actuator, accessible via acyclic data records DS 130 and DS 131.

Safety Shutdown Architectures

Type 8647 supports multiple distinct electrical shutdown configurations for functional safety implementations:

Safety Assessment Responsibility

Manual override operation overrides electrical safety shutdown commands. For safety-critical installations, either protect manual overrides against unintentional manipulation or utilize valve variants without manual override (Article 300818). Ensure exhaust lines vent unrestricted.

1. Fail-Safe Power Module (Siemens F-PM-E): Operates the valve block within the potential group of an ET 200SP F-PM-E 24VDC/8A PPM ST module. Evaluated according to DIN EN ISO 13849-1 and EN IEC 62061. During safety shutdown, load voltage is disconnected and Type 6524 NC valves return to their de-energized closed state. To ensure reliable continuous operation without false tripping, configure F-PM-E dark test parameters:
   • Maximum readback time for dark test / switch-off test: 1.5 ms to 2.5 ms
   • Maximum readback time for switch-on test: 0.8 ms
2. External Valve Shutdown (EVS): Electronic base modules equipped with the EVS terminal provide potential-free contact inputs to isolate coil power across all module valves while maintaining electronics logic, LC displays, and fieldbus diagnostics active.
3. Channel-Specific SIA Shutdown: Available on specialized valve variants featuring dedicated secondary flying-lead connections to shut down individual channels independently via external safety relays.

Cabinet Installation, Maintenance, and Push-In Fitting Guidelines

DIN-Rail Installation

BURKERT 20073326 ships fully pre-assembled on a transport rail. Before mounting in the control cabinet:

1. Loosen all fastening screws fully counter-clockwise and remove the transport rail.
2. Position the valve block on the cabinet DIN rail (grounded with low impedance for EMC protection).
3. Maintain minimum overhead clearance of 50 mm (80 mm if EVS modules are present) to the cabinet wall to prevent thermal build-up and permit tool access.
4. Tighten fastening screws clockwise to approximately 1.8 Nm.

HotSwap Valve Replacement Procedure

Thanks to integrated P-shutoff seats within the pneumatic base module, Type 6524 valves can be replaced without depressurizing the main air header:

1. Secure connected process actuators against uncontrolled physical travel.
2. Loosen the two M2 valve fastening screws using a suitable screwdriver.
3. Extract the valve and its elastomer profile gasket. A brief audible burst of exhaust air occurs until the check mechanism seats.
4. Verify the new valve is a REV.2 variant with an FM20 interface profile.
5. Position the new profile gasket correctly into the valve body recess and seat the valve on the station.
6. Tighten the M2 screws crosswise to 0.15–0.20 Nm.

Revision Compatibility Limit

REV.1 and REV.2 single valves possess different mechanical flange geometries and cannot be interchanged. REV.2 double valves (Type 6524 2x3/2) require matching REV.2 pneumatic base units with FM20 profile gaskets.

Push-In Fitting Connection Rules (ISO 14743:2020)

Working ports use D6 push-in couplings designed for calibrated polyamide (PA) or polyurethane (PU) tubing:

• Tubing Tolerances: D6 mm tubing outer diameter must adhere to ±0.08 mm for PA and ±0.1 mm for PU.
• Preparation: Cut tubing square at 90° using an appropriate hose cutter. Angled cuts reduce retention force and degrade O-ring sealing.
• Insertion: Push tubing firmly past the release ring and internal claw until it bottoms against the internal stop.
• Minimum Retention Force: Connections withstand minimum tensile extraction forces of 120 N for PA tubing and 100 N for PU tubing.

Spare Parts and Ordering Information

Item Description	Revision / Specification	Packaging Unit	Article No.
Replacement Valve Type 6524 2x3/2 NC	24 V DC, 2.5–10 bar, manual override, FM20	1 pc	204710
Replacement Valve Type 6524 2x3/2 NC	24 V DC, 1–10 bar, aux pilot air, manual override	1 pc	300817
Replacement Valve Type 6524 2x3/2 NC	24 V DC, 2.5–10 bar, no manual override	1 pc	300818
Valve Profile Gaskets FM20	For Type 6524 2x3/2-way double valves	12 pcs	20016305
Module Gaskets MP16	Between REV.2 base modules	4 pcs	20024339
Blanking Cover Plate	For Type 6524 2x3/2 double valve slot (REV.2)	1 pc	661092
Electrical Connection Cover	For unused electronic module sockets	1 pc	653670
Left Interface Unit Set	Interface adapter to Siemens ET 200SP BaseUnit	1 set	20029826
Push-In Connector D6 mm (Brass)	Nickel-plated brass tube fittings	8 pcs	20024340
Push-In Connector D6 mm (Stainless)	Stainless steel 1.4401 tube fittings	8 pcs	20024341
Intermediate Supply Unit PSU-M	G 1/4 intermediate feed module	1 pc	20030063