Pass Arrays Larger than 16384 Bytes in EPICS Client and EPICS Server

Updated Jan 29, 2019

Reported In


  • LabVIEW EPICS Client I/O Server

Issue Details

I would like to pass an array larger than 16384 bytes in an EPICS Client or an EPICS Server.  How do I accomplish this?


The default maximum array length of an EPICS Client and an EPICS Server is 16384 (2^14) bytes.  In order to support larger arrays, configuration changes will need to be made depending on the target's operating system.

Refer to the steps in Change EPICS Environment Variables on NI Target  and use the EPICS_CA_MAX_ARRAY_BYTES Environment Variable and a Variable Value of 100000000The EPICS_CA_MAX_ARRAY_BYTES value does not need to be 100000000, but if it is smaller than 16384, the default value, it will be ignored.