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Entry  Fri Nov 17 16:31:11 2017, aaron, Omnistructure, Computers, Acromag wired up AcromagWiringMaps.pdf
    Reply  Fri Nov 17 17:10:53 2017, rana, Omnistructure, Computers, Acromag wired up 
    Reply  Wed Nov 22 00:54:18 2017, johannes, Omnistructure, Computers, Slow DAQ replacement computer progress 
       Reply  Wed Nov 29 21:40:30 2017, johannes, Omnistructure, Computers, Slow DAQ replacement computer progress 
          Reply  Mon Dec 4 22:06:07 2017, johannes, Omnistructure, Computers, Acromag XEND progress 
             Reply  Thu Dec 7 22:24:04 2017, johannes, Omnistructure, Computers, Acromag XEND progress sourcing_input.pngsourcing_to_sourcing_with_common_supply.pngIMG_20171207_193128928.jpg
                Reply  Fri Dec 8 12:06:59 2017, johannes, Omnistructure, Computers, c1auxex2 ready - but need more cables 
Message ID: 13443     Entry time: Wed Nov 22 00:54:18 2017     In reply to: 13434     Reply to this: 13458
Author: johannes 
Type: Omnistructure 
Category: Computers 
Subject: Slow DAQ replacement computer progress 

I got the the SuperMicro 1U server box from Larry W on Monday and set it up in the CryoLab for initial testing.

The specs: https://www.supermicro.com/products/system/1U/5015/SYS-5015A-EHF-D525.cfm

The processor is an Intel D525 dual core atom processor with 1.8 GHz (i386 architecture, no 64-bit support). The unit has a 250GB SSD and 4GB RAM.

I installed Debian Jessie on it without any problems and compiled the most recent stable versions of EPICS base (3.15.5), asyn drivers (4-32), and modbus module (2-10-1). EPICS and asyn each took about 10 minutes, and modbus about 1 minute.

I copied the database files and port driver definitions for the cryolab from cryoaux, whose modbus services I suspended, and initialized the EPICS modbus IOC on the SuperMicro machine instead. It's working flawlessly so far, but admittedly the box is not under heavy load in the cryolab, as the framebuilder there is logging only the 16 analog channels.

I have recently worked out some kinks in the port driver and channel definitions, most importantly:

  • mosbus IOC initialization is performed automatically by systemd on reboot
  • If the IOC crashes or a system reboot is required the Acromag units freeze in their last current state. When the IOC is started a single read operation of all A/D registers is performed and the result taken as the initial value of the corresponding channel, causing no discontinuity in generated voltage EVER (except of course for the rare case when the Acromags themselves have to be restarted)

Aaron and I set 12/4 as a tentative date when we will be ready to attempt a swap. Until then the cabling needs to be finished and a channel database file needs to be prepared.

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