Parker Hannifin
Binary Host Interface
You can enhance communications with the ACR series controller
through the binary host interface.
Binary Data Transfer
The binary data transfers in this chapter consist of a control
character ( Header ID ) followed by a stream of data encoded
according to the current state of the MODE command. Note that
regardless of the mode, the Header ID is never converted during
binary data transfer.
During binary transfers to the card, the delay between bytes must
be no more than the communications timeout setting for the given
channel. If the timeout activates, the transfer is thrown out and the
channel goes back to waiting for a normal character or a binary
header ID. The default communication timeout is 50 milliseconds.
The following is a list of valid data conversion modes. The default
mode for the FIFO channel is zero and the default for the COM1 and
COM2 channels is one. Note that high bit stripping cannot be done
without also activating the control character-prefixing mode.
Mode Description
MODE 0 No Conversion
MODE 1 Control Character Prefixing
MODE 2 No Conversion
MODE 3 Control Character Prefixing and High Bit
Stripping
Control Character Prefixing
Control character prefixing follows Kermit communications protocol
conventions. The escape code for control character prefixing is the
'#' character. The control character-prefixing mode prevents valid
data within a binary packet from being confused with the serial XON
/ XOFF flow control codes.
Transmitting
If the character to be sent is either a 0x7F or a character in the
range of 0x00 to 0x1F, the character is 'XORed' with 0x40 and
proceeded with a '#' character. Otherwise, the byte is sent normally.
For example, if the character to be sent is 0x01, the character is
transmitted as a "#A" string. ( 0x01 XOR 0x40 = 0x41 = 'A' ) The special
case where the character to be sent is the '#' character is handled
with the two character "##" string.
Binary Host Interface 99
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