VIPA SSM-BG41, Manual

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Application of interfaces without data handling blocks Manual BG41/BG42/BG43
4-104 Rev. 99/49
4.2.5.7 Parameter description of STX/ETX
Command 8
Start and end characters and the delay time of the STX/ETX protocol can be altered with this
command.
Standard defaults:
STX 02h
ETX1 03h
ETX2 00h
ZVZ 00h
Mode 00h
This command effects the protocol type STX/ETX (Code 01), which must be activated by command
5. A re-parametrizing during operation is possible.
The command consists of 6 bytes altogether, which are to be sent through the parameter channel 0.
The adjustment is to be carried out separately for each channel.
The ASCII character NUL (00h) is not allowed for the start or end identifier, as this has a special
function. If the parameter ETX2 is loaded with the value 00h, only an end character is evaluated.
ZVZ (Character Delay Time)
The character delay time determines which maximum delay is permitted between the protocol’s
individual characters. The parameter is given in time units to 50 ms. A delay time of 50 ms to 12,75
is therefore adjustable.
Mode
The parameter "Mode" determines the method of the input buffer. With the value 00h, a FIFO with
a depth of 2 telegrams is established. The value 01h establishes a FIFO with a depth of n-telegrams.
As only valid telegrams are transferred to the SPS, these must be saved in between. The telegram
has a maximum length of 255 bytes.
The telegrams on the SPS must be terminated with the ASCII character NUL (00h). All incoming
telegrams, concluded with the ASCII character NUL are transferred to the SPS.