RE: Motor control IOC: Delta Tau GeoBrick register (Y:) access from EPICS

["Mercado, Ronaldo \(DLSLtd, RAL, TEC\) via Tech-talk" <tech-talk at aps.anl.gov>]

Hi,

 

The typical way to achieve this is to map the address to an M variable in the controller and read the M variable from EPICS.

 

I think that for your case the mapping would be

 

M5000 -> Y:$78B20

M5001 -> Y:$78B21

M5002 -> Y:$78B24

M5003 -> Y:$78B25

 

Assuming the “M” variables in that range are available.

 

Reading the M variables depends on the driver that you are using.

 

Some of my systems still use the old tpmac (*) and some newer systems use the pmac driver (**).

 

Do you know which one you are using?

 

This is an example record reading an M variable using pmac

 

record(ai, "example-record:RBV") {

  field(SCAN, "I/O Intr")

  field(PINI, "NO")

  field(DTYP, "asynInt32")

  field(INP, "@asyn(BRICK1,0)PMAC_VIF_M1")

  field(PREC, "0")

  field(EGU, "")

}

 

The corresponding entries in the startup script are

# Create IP Port (PortName, IPAddr)

pmacAsynIPConfigure("BRICK1port", "<ip-address>:1025")

 

# Configure Model 3 Controller Driver (ControlerPort, LowLevelDriverPort, Address, Axes, MovingPoll, IdlePoll)

pmacCreateController("BRICK1", "BRICK1port", 0, 4, 100, 200)

 

This is an example record reading an M variable when using asyn + tpmac

 

record(ai, "example-record:no2") {

  field(DTYP, "stream")

  field(INP, "@pmac.proto getIntVar(M5035) BRICK1port")

}

 

The corresponding entry in the startup script was

 

# Create IP Port (PortName, IPAddr)

pmacAsynIPConfigure("BRICK1port", "<ip-address>:1025")

 

The protocol file pmac.proto comes from the pmacUtil module (+++)

 

 

Regards,

Ronaldo

 

Diamond

 

* https://www.gmca.aps.anl.gov/makarov/TPMAC2/

 

**  https://github.com/DiamondLightSource/pmac/

 

+++ https://github.com/DiamondLightSource/pmacUtil

 

From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of Ha, Kiman via Tech-talk
Sent: 28 February 2026 23:30
To: tech-talk at aps.anl.gov
Subject: Motor control IOC: Delta Tau GeoBrick register (Y:) access from EPICS

 

Hello all,

 

I’m working with a Delta Tau GeoBrick (Turbo PMAC2 family) controlled by an EPICS IOC using a motor record with DTYP=asynMotor.

 

My purpose is to sniff/verify the EIB1512 EnDat2 encoder protocol for a PandABox interface, so I’d like to read the encoder input raw EnDat2 register words directly from the controller, for example:

• Y:$78B20 (EnDat Data A, Ch1)
• Y:$78B21 (EnDat Data B, Ch1)
• Y:$78B24 (EnDat Data A, Ch2)
• Y:$78B25 (EnDat Data B, Ch2)

 

From the motor record I see:
• XF:23ID2-OP{Mono-Ax}Mtr.DTYP = asynMotor
• XF:23ID2-OP{Mono-Ax}Mtr.OUT = @asyn(motor,2)

 

Any suggestions on the recommended way to read these Y: registers as raw words from the IOC (e.g., via an asynOctet port/asynRecord, or a standard PMAC/GeoBrick register PV template).

 

Thanks,

Kiman

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