PAC 100 Programmable Automation Controller as a Replacement for the 647C

photo - MKS PAC 100

The MKS PAC 100 Programmable Automation Controller is now available as a replacement for the discontinued 647C Multichannel Gas Flow & Pressure Controller. The 647C Controller was a multichannel controller that read pressure from MKS Baratron® Capacitance Manometers to control Mass Flow Controller (MFC) flow with DSUB interfaces. It was configured with 6 preprogrammed control modes.

The new PAC 100 is a fully-programmable automation controller offering many additional features and enhancements over the 647C controller. MKS Programmable Automation Controllers (PAC) merge the features of Programmable Logic Controllers (PLC) and Industrial Personal Computers (IPC), to create an open standards, networked, programmable, flexible, and scalable PAC, all in a modular, DIN rail mountable plastic enclosure. Compared to standard PLC's and IPC's, MKS PAC's provide a more compact, customizable, high performance, and cost effective programmable control solution for a variety of control and automation tasks.

The PAC 100 reads pressure from MKS Baratron® manometers and controls MFC flow with 15-pin or 9-pin MFC Modules. It is fully compliant to IEC-61131-3 standards.

PAC 100 versus 647C:

The PAC 100 is a fully programmable controller that can daisy-chain up to 20 customizable I/O modules. This provides a flexible automation solution system when compared to controllers with hard-wired I/O channels that are not fully programmable, like the 647C.

  • Reduced cost
  • Simplified wiring
  • Smaller hardware footprint
  • I/O channel customizability
  • Full IEC-61131-3 programmability
  • Compatible with modern 24 VDC power supplies


PAC 100 Controller and MFC Modules are daisy-chained together, using backplane for power and communication. Each MFC module has 4 connectors, either 9-pin DB or 15-pin DB. If 1 connector is used as the pressure gauge input, then the remaining 3 connectors can be used for MFC flow outputs to produce 1 closed loop pressure control system. Up to 20 MFC modules (after adding power modules to provide additional power) may be used to attain the desired MFC flow requirement. The 24V power supply connects to the PAC 100 with two 3-pin connectors.

PAC 100 solutions feature small compact module units, replacing the large 647C controller. Four PAC 100 variations are offered:

  • PAC 100, Power Supply, one 9-pin MFC module (supports 1 loop, 1-3 MFC flow outputs)
  • PAC 100, Power Supply, two 9-pin MFC modules (supports 1 loop, 4-7 MFC flow outputs)
  • PAC 100, Power Supply, one 15-pin MFC module (supports 1 loop, 1-3 MFC flow outputs)
  • PAC 100, Power Supply, two 15-pin MFC modules (supports 1 loop, 4-7 MFC flow outputs)


The PAC 100 preferred user interface is Controls Workbench (CWB) Software, replacing the 647C LCD display function. MKS Controls Workbench is a central interface for communicating with most MKS controllers and creates custom dashboards for individual or multiple MKS controllers on the same network. CWB software will install on any PC running Windows 7 or above. The PC running Controls Workbench will interface with the PAC 100 with a standard Modbus TCP/IP connection.


The PAC 100 & Controls Workbench software will account for the MFC's calibration based on its Gas Correction Factors for the chosen gas, replacing the 647C calibration Gas Selection menu function.

Control Mode Selection:

The PAC 100 is a fully-programmable controller with 6 preprogrammed "images" for each control mode (Independent, Slave, External, PCS, PID, Test Mode). A user can transfer the image to the PLC using Controls Workbench and initiate the logic sequence upon PLC bootup. This will allow users to monitor the pressures and control MFC flow rates with preprogrammed "dashboards". This replaces the 647C control mode functions.

More Information:

Need help?

Contact an Applications Specialist by sending an email to A&, or call 512-719-8000.