Waveforms are always sent in Channel Access as it assumes that something about the waveform changed. The primary use of this was scope traces. The chance that two analog signals would produce the same array is so unlikely that they arrays are sent every time the record is processed. IOC core was developed to maximize throughput and record processing, these compares would have been done at the highest priority thread on a single processor system - so it was not even considered.
The scalar value monitor handling is covered in the Record Reference Manual.
Bob
