101501-565 Rev C
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6.7 SPELLMAN TEST COMMANDS
Program Hardware Version (Hardware setup)
Program Model number(Hardware setup)
Store A/D Calibration Value (Hardware setup)
Request Miscellaneous Analog Readbacks
Contact Spellman High Voltage for details and the syntax of these
commands.
6.8 SERIAL COMMAND HANDLING
6.8.1 Command Time Out
The host computer should set a serial time out at approximately 100mS.
This allows the DSP to process the incoming message, and transmit a
response. The DSP will initiate a reply to incoming messages in
approximately 1-2mS, with a worst case of 5mS.
6.8.2 Buffer
Flushing
The DSP will flush the incoming serial data buffer every time an STX is
received. This provides a mechanism to clear the receive buffer of partial
or corrupt messages.
6.8.3 Handshaking
The only handshaking implemented on the host interface, is built in to the
implementation of this protocol. That is, the host must initiate all
communications. If the supply receives a program command, an
acknowledge message is sent back to the host via the “$” message. If the
host does not receive an acknowledge within the time out window, the
host should consider the message lost or the device off-line.
Similarly, if the supply receives a request command, the requested data is
sent back to the host. If the host does not receive the requested data
within the time out window, the host should consider the message lost or
the device off-line.
This essentially uses the full-duplex channel in a half-duplex
communication mode.