PLC Communication Modules

Showing 97 - 120 of 234 products

$423.00

Only 3 units left

Buy the Siemens 6DD1642-0CC0 I/O Module - an industrial input/output module providing signal interfacing for Siemens automation systems. Features reliable signal conditioning, industrial-grade isolation, and seamless Siemens platform integration. The Siemens 6DD1642-0CC0 is a direct replacement for existing I/O installations.

Siemens 6DD1681-0AE2 Siemens

$517.02

Only 5 units left

Product
Article Number (Market Facing Number)	6DD16810AE2 \| 6DD16810AE2
Product Description	* spare part * SIMATIC TDC, binary input or output SB10 8 BI or 8 BO, 24 V DC LED display
Product family	Not available
Product Lifecycle (PLM)	PM410:Product cancellation
Additional Product Information
EAN	Not available
UPC	662643297317
Commodity Code	85389091
LKZ_FDB/ CatalogID	ST.DA99
Product Group	4476
Group Code	R132
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	0.794 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD1601-0AE0 Siemens

$5,228.30

Only 9 units left

Product
Article Number (Market Facing Number)	6DD16010AE0 \| 6DD16010AE0
Product Description	* SPARE PART* SIMADYN D, PROCESSOR MODULE PG16 LINE-COMMUTATED CONVERTERS
Product family	Not available
Product Lifecycle (PLM)	PM500:Discontinued Product or end of PLM & Support
Additional Product Information
EAN	Not available
UPC	662643265538
Commodity Code	85049099
LKZ_FDB/ CatalogID	ST9.DA99T
Product Group	4230
Group Code	R111
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	1.457 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD1606-1AD0 Siemens

$4,119.69

Only 3 units left

Product
Article Number (Market Facing Number)	6DD16061AD0 \| 6DD16061AD0
Product Description	* SPARE PART* SIMADYN D PROCESS MODULE PT20M TECHNOLOGY 16 BIT, 20MHZ WITH COUPLING MEMORY 64KB FOR L-BUS
Product family	Not available
Product Lifecycle (PLM)	PM500:Discontinued Product or end of PLM & Support
Additional Product Information
EAN	Not available
UPC	662643034714
Commodity Code	85371091
LKZ_FDB/ CatalogID	ST9.DA99T
Product Group	4230
Group Code	R111
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	1.495 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD1607-0AA2 Siemens

$9,346.05

In stock, 15 units

Product
Article Number (Market Facing Number)	6DD16070AA2 \| 6DD16070AA2
Product Description	SIMATIC S7-400, FM458-1 DP application group for SIMATIC S7-400
Product family	Not available
Product Lifecycle (PLM)	PM410:Product cancellation
Additional Product Information
EAN	4019169134828
UPC	Not available
Commodity Code	85389091
LKZ_FDB/ CatalogID	ST.DA99
Product Group	4100
Group Code	R132
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	2.562 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD1681-0CD0 Siemens

$531.26

Only 3 units left

Buy the Siemens 6DD1681-0CD0 - a genuine Siemens industrial automation component engineered for reliable performance in demanding manufacturing and process control environments. The Siemens 6DD1681-0CD0 is a direct drop-in replacement for existing installations and ships ready for integration.

Siemens 6DD1682-0CC0 Siemens

$26,985.15

Only 7 units left

Product
Article Number (Market Facing Number)	6DD16820CC0 \| 6DD16820CC0
Product Description	* SPARE PART* SIMADYN D SUBRACK SR12.1 24V DCINTEGRATED FAN 12 SLOTS , L- AND C-BUS
Product family	Not available
Product Lifecycle (PLM)	PM500:Discontinued Product or end of PLM & Support
Additional Product Information
EAN	Not available
UPC	662643270181
Commodity Code	85049099
LKZ_FDB/ CatalogID	ST9.DA99T
Product Group	4230
Group Code	R111
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	23.149 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD1-688-0AE2 Siemens

$1,082.33

Only 6 units left

Product
Article Number (Market Facing Number)	6DD16880AE2 \| 6DD16880AE2
Product Description	* SPARE PART* SIMADYN D COMMUNICATION SUBMODULE SS52 FOR CS7 , MASTER INTERFACE FOR BUS SYSTEM SINEC L2 DP
Product family	Not available
Product Lifecycle (PLM)	PM500:Discontinued Product or end of PLM & Support
Additional Product Information
EAN	Not available
UPC	662643270105
Commodity Code	85176200
LKZ_FDB/ CatalogID	ST9.DA99T
Product Group	4230
Group Code	R111
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	0.403 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD1611-0AG0 Siemens

$2,510.88

Only 9 units left

Product
Article Number (Market Facing Number)	6DD16110AG0 \| 6DD16110AG0
Product Description	* SPARE PART* SIMADYN D MAILBOX MM4 , 32BIT L- AND C-BUS , EACH 2MB RAM SYSTEM ERROR SIGNAL OUTPUT
Product family	Not available
Product Lifecycle (PLM)	PM500:Discontinued Product or end of PLM & Support
Additional Product Information
EAN	Not available
UPC	662643338805
Commodity Code	85389091
LKZ_FDB/ CatalogID	ST9.DA99T
Product Group	4230
Group Code	R111
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	0.882 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD1681-0DH0 Siemens

$351.79

Only 3 units left

Buy the Siemens 6DD1681-0DH0 Communication Module - an industrial network interface providing controller-to-device connectivity. Supports standard industrial protocols for seamless automation integration. The Siemens 6DD1681-0DH0 is a direct replacement for existing communication installations.

Siemens 6DD1640-0AE0 Siemens

$4,911.78

Only 9 units left

Buy the Siemens 6DD1640-0AE0 I/O Module - an industrial input/output module providing signal interfacing for Siemens automation systems. Features reliable signal conditioning, industrial-grade isolation, and seamless Siemens platform integration. The Siemens 6DD1640-0AE0 is a direct replacement for existing I/O installations.

Siemens 6DD1600-0AC0 Siemens

$4,765.20

Only 3 units left

PLC Direct is not an authorized distributor. We offer a broad range of in-stock products with minimal lead time.

Siemens 6DD1610-0AG6 Siemens

$456.00

Only 1 unit left

PLC Direct is not an authorized distributor. We offer a broad range of in-stock products with minimal lead time.

Siemens 6DD1601-0AF0 Siemens

$6,405.00

Only 4 units left

Product
Article Number (Market Facing Number)	6DD16010AF0
Product Description	* SPARE PART* SIMADYN D, PROCESSOR MODULE PG26 DC CURRENT 16 BIT , 16MHZ L-BUS , 4 BI AL., 4BO TWO SITOR INTERFACES
Product family	Not available
Product Lifecycle (PLM)	PM500:Discontinued Product or end of PLM & Support
Additional Product Information
EAN	Not available
UPC	Not available
Commodity Code	85371091
LKZ_FDB/ CatalogID	ST9.DA99T
Product Group	4230
Group Code	R111
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	1.861 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD2920-0AS1 Siemens

$852.80

Only 3 units left

Buy the Siemens 6DD2920-0AS1 - a genuine Siemens industrial automation component engineered for reliable performance in demanding manufacturing and process control environments. The Siemens 6DD2920-0AS1 is a direct drop-in replacement for existing installations and ships ready for integration.

Siemens 6DD1607-0CA0 Siemens

$5,725.40

Only 5 units left

Product
Article Number (Market Facing Number)	6DD16070CA0 \| 6DD16070CA0
Product Description	* SPARE PART* SIMATIC S7-400, EXM 438 I/O EXPANSION MODULE FOR FM 458
Product family	Not available
Product Lifecycle (PLM)	PM500:Discontinued Product or end of PLM & Support
Additional Product Information
EAN	Not available
UPC	662643355215
Commodity Code	85389091
LKZ_FDB/ CatalogID	ST9.DA99T
Product Group	4100
Group Code	R111
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	2.407 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD1606-1AA02 Siemens

$0.00

Sold Out

Buy the Siemens 6DD1606-1AA02 - a genuine Siemens industrial automation component engineered for reliable performance in demanding manufacturing and process control environments. The Siemens 6DD1606-1AA02 is a direct drop-in replacement for existing installations and ships ready for integration.

Siemens 6DD1610-0AH4 Siemens

$716.91

Only 1 unit left

Product
Article Number (Market Facing Number)	6DD16100AH4 \| 6DD16100AH4
Product Description	SIMATIC TDC MC500 memory module 4 MB Flash-EPROM, 8 KB EEPROM
Product family	Not available
Product Lifecycle (PLM)	PM410:Product cancellation
Additional Product Information
EAN	4025515739722
UPC	662643034813
Commodity Code	85235110
LKZ_FDB/ CatalogID	ST.DA99
Product Group	4476
Group Code	R132
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	0.106 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD1600-0BA3 Siemens

$20,674.87

Only 7 units left

Product
Article Number (Market Facing Number)	6DD16000BA3 \| 6DD16000BA3
Product Description	SIMATIC TDC, CPU551 64-bit processor module with digital inputs
Product family	Not available
Product Lifecycle (PLM)	PM410:Product cancellation
Additional Product Information
EAN	4047622103890
UPC	887621839086
Commodity Code	85371091
LKZ_FDB/ CatalogID	ST.DA99
Product Group	4476
Group Code	R132
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	0.002 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD1681-0AJ1 Siemens

$981.00

Only 5 units left

Product
Article Number (Market Facing Number)	6DD16810AJ1 \| 6DD16810AJ1
Product Description	* spare part * SIMATIC TDC, converter SU12 10-pole 10 screw-type plug-in terminals 10-pole connector
Product family	Not available
Product Lifecycle (PLM)	PM410:Product cancellation
Additional Product Information
EAN	Not available
UPC	662643035018
Commodity Code	85389091
LKZ_FDB/ CatalogID	ST.DA99
Product Group	4476
Group Code	R132
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	0.739 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD1682-0BC3 Siemens

$12,791.83

Only 7 units left

Buy the Siemens 6DD1682-0BC3 - a genuine Siemens industrial automation component engineered for reliable performance in demanding manufacturing and process control environments. The Siemens 6DD1682-0BC3 is a direct drop-in replacement for existing installations and ships ready for integration.

Siemens 6DD1640-0AB0 Siemens

$2,458.59

Only 2 units left

PLC Direct is not an authorized distributor. We offer a broad range of in-stock products with minimal lead time.

Siemens 6DD1661-0AE1 Siemens

$7,580.82

Only 7 units left

Product
Article Number (Market Facing Number)	6DD16610AE1 \| 6DD16610AE1
Product Description	SIMATIC TDC communications module CP51M1 for Industrial Ethernet with TCP/IP and/or UDP
Product family	CP51M1 communications module
Product Lifecycle (PLM)	PM400:Announcement of product phase-out
Additional Product Information
EAN	4019169134675
UPC	662643297300
Commodity Code	85176200
LKZ_FDB/ CatalogID	ST.DA99
Product Group	2310
Group Code	R132
Country of origin	Germany
SCIP number	2c5b920b-ad93-41a6-82eb-f2ef14cd3201
Delivery information
Net Weight (lb)	0.002 lb
Package size unit of measure	Inch
Packaging Quantity	1

Siemens 6DD1601-0AH0 Siemens

$1,667.15

Only 5 units left

Product
Article Number (Market Facing Number)	6DD16010AH0 \| 6DD16010AH0
Product Description	* SPARE PART* SIMADYN D EXPANSION MODULE ITDC FOR PM4. PM5. PM6 CONTROL F. LINE-COMMUTATED CONVERTERS VIA SITOR IF
Product family	Not available
Product Lifecycle (PLM)	PM500:Discontinued Product or end of PLM & Support
Additional Product Information
EAN	Not available
UPC	662643265521
Commodity Code	85389091
LKZ_FDB/ CatalogID	ST9.DA99T
Product Group	4230
Group Code	R111
Country of origin	Germany
SCIP number	Not available
Delivery information
Net Weight (lb)	1.208 lb
Package size unit of measure	Inch
Packaging Quantity	1

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PLC communication modules are plug-in hardware cards that extend a programmable logic controller's network connectivity, enabling data exchange with field devices, other controllers, SCADA systems, and enterprise networks via protocols such as PROFIBUS, PROFINET, EtherNet/IP, CC-Link, and Modbus. PLC Direct supplies PLC communication modules as an independent supplier, carrying surplus sealed, refurbished, and used hardware for maintenance and replacement in installed PLC systems.

Where Are PLC Communication Modules Used in Industrial Environments?

PLC communication modules are used wherever a controller must exchange data with field devices, distributed I/O, drives, HMIs, or higher-level systems over an industrial network protocol. These modules are installed in the PLC rack or backplane and handle all protocol-level communication independently of the CPU's primary scan cycle.

Facilities and operations that depend on PLC communication modules include:

Discrete manufacturing plants connecting PLC controllers to distributed I/O stations, servo drives, and robot interfaces over PROFIBUS or PROFINET.
Automotive assembly operations requiring high-speed, deterministic network communication across multi-PLC production line architectures.
Process industry facilities integrating PLCs with DCS systems, field instruments, and SCADA platforms over Modbus TCP or EtherNet/IP.
Water and wastewater treatment plants using communication modules to connect remote pump station controllers to centralized SCADA networks.
Food and beverage processing facilities coordinating PLC-to-PLC data exchange across filling, packaging, and conveyor control systems.

A failed or discontinued PLC communication module can isolate an entire controller from its network, making replacement availability a direct operational priority for maintenance teams.

Which Brands of PLC Communication Modules Does PLC Direct Stock?

PLC Direct stocks PLC communication modules across the major controller platforms and industrial network protocols deployed in installed automation systems worldwide.

Siemens SIMATIC CP343 and CP443 series: Communications processors for SIMATIC S7-300 (CP343-1) and S7-400 (CP443-1) controllers, covering Industrial Ethernet via TCP/IP, PROFINET IO, and S7 communication protocols.
Mitsubishi Electric MELSEC Q Series network modules: QJ71E71-100 Ethernet interface modules and QJ61BT11N CC-Link master/local modules for MELSEC Q Series systems, enabling Ethernet and CC-Link network connectivity within installed Q Series architectures.
Omron CJ Series communication modules: CJ1W-EIP21 EtherNet/IP communication modules for CJ Series PLC systems, supporting EtherNet/IP tag data link and message communication with compatible field devices and controllers.
ABB S500 communication interface modules: CI541-DP PROFIBUS and CI592-CS31 interface modules for AC500-based systems, extending distributed I/O connectivity across PROFIBUS DP and CS31 fieldbus networks.

PLC Direct carries PLC communication modules as surplus sealed, refurbished, and used hardware, giving maintenance teams options across condition grades and budget requirements.

What Should You Know Before Ordering PLC Communication Modules?

Hardware condition options: PLC Direct supplies PLC communication modules in surplus sealed, refurbished, and used conditions. Surplus sealed units are factory-sealed stock that has not been previously installed; refurbished modules have been inspected and tested to confirm operational functionality; used hardware is sourced from decommissioned systems and suits facilities managing lifecycle replacements under budget constraints.

Compatibility and part identification: PLC communication modules are platform-specific and must be matched to the correct controller series, rack slot type, and firmware environment. A CP343-1 for the S7-300, for example, is not compatible with an S7-400 rack. Confirm the full part number, controller series, and target protocol from the installed system's hardware documentation or network configuration before ordering.

Warranty: All PLC communication module hardware purchased from PLC Direct carries a standard 1-year PLC Direct warranty covering defects and functionality, applicable to surplus sealed, refurbished, and used products.

PLC Direct supplies PLC communication module hardware for replacement and maintenance purposes and does not provide system design, programming, or integration services.

Frequently Asked Questions

A PLC communication module handles network protocol processing independently of the controller CPU, managing data exchange with field devices, distributed I/O, drives, and higher-level systems over protocols such as PROFIBUS, PROFINET, EtherNet/IP, and CC-Link. By offloading network communication to a dedicated module, the CPU scan cycle is not interrupted by network traffic, maintaining deterministic control performance.

In most cases a like-for-like replacement of the same part number will restore network communication without changes to the controller program, as the module's protocol configuration is typically stored in the CPU project rather than in the module itself. However, some platforms require the module to be initialized or assigned a network address during commissioning, so the system's network configuration documentation should be reviewed before installation.

PROFIBUS is a serial fieldbus protocol operating over RS-485 physical layer at data rates up to 12 Mbps, widely installed in legacy automation systems from the 1990s onward. PROFINET runs over standard Industrial Ethernet infrastructure at 100 Mbps or higher and supports real-time and isochronous communication modes; it is the current standard for Siemens-based networks and increasingly predominant across other platforms. Modules for each protocol are not interchangeable even within the same controller family.

The most reliable method is to read the part number directly from the installed module's label and cross-reference it against the controller's hardware manual to confirm the rack slot type, protocol, and firmware compatibility. For Siemens S7-300 and S7-400 systems, the CP part number encodes both the protocol and the controller family it is designed for.

Many communication modules for legacy platforms including the Siemens SIMATIC S7-300 CP343 series and Mitsubishi MELSEC Q Series network modules remain available through independent suppliers even after manufacturer discontinuation, as installed base demand continues well beyond the end of production. Contact PLC Direct with the part number to check current availability.