EUROTHERM: test DLS MODBUS driver [Timebox: 0.5 day]

[davidkeymer]

As a developer, I would like to find out whether or not the MODBUS Eurotherm driver written by the Diamond Light Source (DLS) is suitable to be used in the IBEX system. This would potentially save a lot of time and effort, as well as provide an opportunity to use shared code and promote collaboration.

Acceptance Criteria

• A decision is made whether to use the DLS driver, or parts thereof, or write one from scratch

Extra Information

Other tickets relating to this work:

• Original ticket documenting the requirements.
• Needle valve using MODBUS protocol which is required for WISH migration. Planned to be used throughout all ISIS instruments eventually.

DLS driver here

[FreddieAkeroyd]

Diamond driver is now part of our build at support/eurothermModbus/master

[Tom-Willemsen]

Direct feature comparison of our existing EI-BISYNCH driver and the diamond modbus driver:

Feature	ISIS driver	Diamond modbus driver
Temperature readback	Yes	Yes ($(device):LOOP1:PV:RBV)
Temperature setpoint	Yes	Yes ($(device):LOOP1:SP)
Temperature setpoint readback	Yes	Yes ($(device):LOOP1:SP)
Changeable temperature units	Yes	No (hardcoded to C)
Output readback	Yes	Yes ($(device):LOOP1:O:RBV)
Output setpoint	No	Yes ($(device):LOOP1:O)
Max output set/read	Yes	Yes ($(device):LOOP1:OUTPHI, $(device):LOOP1:OUTPHI:RBV)
Min output set/read	No	Yes ($(device):LOOP1:OUTPLO, $(device):LOOP1:OUTPLO:RBV)
Ramp rate set/read	Yes	Yes ($(device):LOOP1:RR, $(device):LOOP1:RR:RBV)
Ramp on/off	Yes	No
Autotune set/read	Yes	Yes ($(device):LOOP1:AUTOTUNE, $(device):LOOP1:AUTOTUNE:RBV)
Auto/manual set/read	No	Yes ($(device):LOOP1:MAN, $(device):LOOP1:MAN:RBV)
PID set/read	Yes	Yes
PID & max output lookup	Yes	No
Temperature calibration files	Yes	No
Run eurotherm programs	No	Yes (see eurothermProg.template)
Loops supported	10	2
Disable records	Yes	Yes, and automatically set when device goes into error.
Sim records	Yes	No
interest/archive records	Yes	No

I was unable to get our office eurotherm to respond on modbus using diamond's IOC. More investigation may be required on this, but I've reached the end of the timebox. I've pushed the eurotherm_modbus branch to EPICS-ioc which contains the test IOC I used. Note: configuration passwords for eurotherm (to switch between comms modes) are now stored in keeper.

The stages you need to use to change between comms setups on the office eurotherm are:

• Power cycle the unit while holding down the up & down arrow keys simultaneously
• Once the unit comes up asking for a passcode, enter the configuration password (from keeper)
• Navigate to the "comms" menu section, scroll down to "protocol" and select EI-BISYNCH or MODBUS as appropriate
• Check the baud rate in the comms menu as this sometimes changes as you change between comms modes
• Navigate back to the config section of the menu, and select "GOTO" -> "Level 3".
  • Note that the eurotherm WILL NOT communicate while it is in the config mode
• The eurotherm should now communicate on the selected protocol.

I was unable to get any bytes back from the device when using the modbus protocol.

Next steps:

• Understand why our office eurotherm doesn't communicate on MODBUS at all using diamond's setup
• If we decide to proceed with using the diamond driver, write tickets to reimplement the missing functionality described in the table above
  • We will also need to decide whether to rename the PVs to existing ISIS conventions, or keep the diamond PVs which would require scripts/blocks etc to be updated

[KathrynBaker]

Given the above, it is fair to say that the DLS driver is not working for us, there is also enough functionality missing that at best we will be able to use parts of that driver, and it will be worth migrating those into our Eurotherm driver.

[FreddieAkeroyd]

After switching to 8 bit RTU mode and updating our epics modbus module from 2.6 to 2.10.1 (required for absolute modbus addressing that the diamond driver uses) this now all seems to work on the office eurotherm