Metasys and Modbus Drivers

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Metasys and Modbus Drivers

• Bob Dalesio
• May 20, 1999

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Modbus Use at LEDA
EPICS - IOC
PLC

RFQ Vacuum
Lab-View
Local Interlocks Scan Inputs Control Outputs
Start-up Scan Muxd I/O Read Inputs Send Control
Requests
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Modbus Use at LEDA

• Vacuum system developed at LLNL using Labview
• Discussions about EPICS integration led to place
  interlocks in the PLC and startup and
  multiplexing sequences in Labview (to be replaced
  by EPICS)
• Vacuum fully tested and delivered using Labview
• Integration done running both Labview and EPICS
  to the PLC
• Project engineering for RFQ vacuum done with
  minimal interaction with LLNL personnel
• Most important portion was to agree on what was
  to be in the PLC and how EPICS would interface to
  it.

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Metasys Use at APS
5 second communication delay
20 second communication delay

Metasys to AB Data Highway
PLC
PLC
PLC

EPICS - IOC


LAN
Building and cooling water control
Stand Alone Controls
APS Control Room
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Data Highway to Metasys Use at APS

• Original design dictated that the cooling water
  to the RFQ would not need to be interfaced to the
  APS controls
• Discovered that the temperature of the RFQ had an
  affect on the tune of the cavity.
• Original interface went through the IOC to an
  AB-PLC to an AB KF2 protocol converter - to a
  Johnson controls network interface and took over
  2.5 minutes to see an update. It also required
  programming on the PLC and KF2.
• Latest modification reduces communication time to
  once every 25 seconds.
• Fully integrating all signals into the control
  system from the design phase would cover any
  unforeseen needs.