Instron stress rig

Setup

The Instron stress rig is a National Instruments GPIB device. It requires some special setup to get going:

• The Ethernet GPIB box requires a driver for the LabVIEW driver. This can be installed from \olympic\Babylon5\Public\GHowells\NI GPIB
• Run the installer as an administrator, accept the defaults. It will unzip, then install. It takes a while to install.
• You then need to set up the ENET box, Gareth or Freddie can show you how to set this up
• LabVIEW vi located at : C:\LabVIEW Modules\Instruments\ENGINX\Stress Rig\Stress Rig - System Functions.llb\Stress Rig - 100 kN Stress Rig.vi
• On running the vi, you will get some dialogs – just ok through them. The indicators should then be updating.
• If you can't get the labview to talk at all, the stress rig might need to be power cycled. @GDH-ISIS and @FreddieAkeroyd know how to do this. The basic instructions are below:
  • Turn off the stress rig PC (white/beige pc located under the stress rig)
  • Turn off the GPIB box (this looks similar to a router, located under the stress rig near to the stress rig PC)
  • Wait a few seconds
  • Turn on the stress rig PC
  • Wait several minutes. The stress rig will go through a self-test phase. You need to wait for this process to be complete.
  • If you need to calibrate the rig, the following sequence on the console should be used: "Load channel: setup" -> "cal" -> "cal" -> "auto" -> "go" (if you are unsure about this ask the scientists)
  • Turn back on the GPIB box.
  • After the GPIB box has been turned on for a short time (e.g. 1 minute) the driver (LabVIEW or IOC) should be ready to connect.
  • GPIB box LEDs - PWR should be orange, LNK 10/100 should be green. Other LEDs will be flickering depending on connection. Box might have a slightly dodgy connection (not sure about this, but check it) so ensure the LEDs are as described.

Rigs

There are two rigs: 50kN and 100kN.

To turn on the actuator for the 100kN rig, there are three buttons on the front labelled "O", "I", "II". Press these in order to enable the actuator.

To turn on the actuator for the 50kN rig, Press and hold the "Hydraulics on" button for at least 10 seconds. You should hear the hydraulic system engage (also, the hydraulic lines will change position slightly). Then press actuator "off", "low", "high" (in order) to enable the actuator.

Hardware debugging

• If the hydraulics on the rigs keep tripping off and the rig returns a status of "oil too hot"

Check if the cooling water circuit for TS1 south side is turned on. If not, the instron's oil might heat up too much which causes the hydraulics to trip when moving the rig. This happens regardless of whether IOC, LabVIEW, or manual control is used to move the actuator. Additional symptoms are a rig status of "HYD. PUMP SHUTDOWN" and the red status light on the control panel being solidly on (and not being able to clear it).

If the cooling water is off, there is a circulation pump that can be used to run the rig in low-force mode: ask the scientists.

Driver

The stress rig driver uses the following DB files:

• controls.db - provides basic PVs such as stopping the rig, getting the status, changing control channels, etc
• controls_channel.db - provides PVs that are common to each channel (Position, Stress, Strain), e.g. setpoints, readbacks, step times
• controls_channel_specific.db - add on PVs for the above - used to add PVs for some channels that don't exist on others
• controls_waveform.db - provides the PVs dealing with the waveform generator
• logging.db - provides the PVs to do with logging to a file

The protocol is defined in C:\Instrument\Apps\EPICS\support\instron\master\instronSup (see https://github.com/ISISComputingGroup/EPICS-instron/blob/master/instronSup/devinstron.proto)

Gotchas / Unusual things

• Every "write" command (commands starting with C or P) must be preceded by P909,1 (switch to computer control mode) and C904,0 (disable watchdog). For convenience there is the setControlModeCom function in the protocol file which does these for you.
  • If you forget to do this, the rig's hydraulics will trip, requiring a physical button push to reset them
• Every "write" command (commands starting with C or P) must be followed by P909,0 (switch to front panel control mode)
• We have had issues with PVs dropping off to zero while being read from the stress rig. To solve this, use a :RAW record which does a read, and monitor it using CP from another record. This fixes the issue of getting zeroes.
  • Might be a bug in EPICS and/or the interface between the VISA driver and EPICS. At the moment the above solution seems to be the easiest way to cure the symptoms.
• PVs in the stress rig don't scan by themselves typically, they are triggered from one of two read loops:
  • READ_SLOW scans at 1 Second interval
  • READ_VAR reads at a rate that can be varied by the user
  • In the READ_VAR loop the .1 Second option has been removed, this is too fast for the rig to handle
• If something works in LabVIEW but not in EPICS, or vice-versa, NI Input/Output trace (NI Spy) can be very useful to compare the traffic and spot any differences.
• The waveform generator does not like recieving setpoints in quick succession. This can cause a fault with the following symptoms:
  • The "remote" light on the hardware control panels remains lit
  • The hardware control panel crashes (it may display that it's in two control channels simultaneously - this is usually impossible
  • The hydraulics will trip.