Experimental Physics and
Industrial Control System

Ralph Lange <[email protected]> · Wed, 10 Sep 2014 11:02:30 +0200

On 10/09/2014 10:30, [email protected] wrote:

The outuput of cainfo is
LEBT:LEBT:PS:STH1:OPER:CurrSP
     State:            connected
     Host:             10.30.0.10:5064
     Access:           read, write
     Native data type: DBF_DOUBLE
     Request type:     DBR_DOUBLE
     Element count:    1

Full access - no firewall and/or access security issue. Good.

What value are you trying to write to which field of what record type?

This is the current setpoint of a power supply.
The IOC db file contains this information
record(ai,"LEBT:PS:STH1:OPER:CurrSP"){
   field(INP,"LV:LEBT:PS:STH1:OPER:CurrSP CP")
   field(DESC,"PS EXT Voltage")
   field(DESC, "LEBT STH1 Current SP")
}

I guess that I am trying to change the INP field which has no access
permission according to the Record Reference Manual, isn't it?
In this case how is possible that the value can be changed with the CSS GUI?
Should have the record a VAL field?

This input record is configured (through its INP setting) to get its

value from LV:LEBT:PS:STH1:OPER:CurrSP, whenever that record's value

changes.

Writing to the INP field will change the record's configuration to point

to another source for the value.

Writing to the VAL field is probably closer to what you want, but still

- your caput changes the value and processes the record, then during

that processing the record does what it is configured to: it reads the

value from the configured location LV:...:CurrSP.

Bottom line:

If you configure your input record to pull its value from another

location, you cannot change the value by writing to it, and vice versa.

Hint:

Maybe the simulation mode (again: described in the Application

Developers Guide and the Record Reference Manual) is able to achieve

what you want. It allows you to switch your input record into simulation

mode (.SIMM), where it will not use the configured INP link, but a

special simulation link or value (.SIOL) to fetch its value.

Sorry if they are trivial questions; but I new to EPICS.

I would suggest participating at a training. The next public one is held

as part of the EPICS collaboration meeting end of October in Saclay

(Paris), France. There are also people and companies that can provide

in-house training, if that is more appropriate.

Good luck!
~Ralph

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System