[Question] Is there any one using Keithley 2400 source meter

[reactgary]

Hi,

I am using a Keithley 2400 source meter with some linux C programming
All command works.
However, when I issue a "READ?" command
The source meter will show me a "ERROR: ID CODE = -110 " Message

Would anyone help me to solve this problem?
our anyone has experiences using this source meter with linux as
interface?

Thank You

GaRY