Timing data - Agilent and PMAC handshake

With the Agilent laser interferometer providing position inputs, the Delta Tau ACC-14D board will be operated in Method 4: the ACC-14D raises OCLK to signal a desire to read new encoder positions, and the Agilent board raises ICLK when it has valid positions ready to be read (see pp. 4-8 and 6-6 of the Agilent N12131A manual, and pp. 27-28 of the ACC-14D manual).

With the NI PCI-6534 board providing position inputs, the Delta Tau ACC-14D board will be operated in Method 3: the PCI-6534 ACK output will be used to provide a rising edge to ICLK into the Delta Tau board to indicate valid positions to be read on the next Delta Tau servo cycle (see Fig. 7.2).

Note that it appears that the response of the Delta Tau board to ICLK inputs appears to be the same in methods 3 and 4: in both cases, it loads the encoder position when the encoder provides a rising edge on the Delta Tau ICLK input. In method 3, the encoder ignores the Delta Tau OCLK output and simply provides encoder outputs when it wishes (raising ICLK when they are valid). In method 4, the encoder provides outputs in response to the Delta Tau board having raised OCLK.