6
Protocol 2000
The VA-4 is compatible with Kramer’s Protocol 2000 (version 0.51). This RS-232 /
RS-485 communication protocol uses four bytes of information as defined below.
For RS-232, a null-modem connection between the machine and controller is
used. The default data rate is 9600 baud, with no parity, 8 data bits and 1 stop bit.
The first table below lists the VA-4 Hex codes for gain control (attenuation), and
the second table below lists the VA-4 Hex codes for gain control (amplification). In
addition, the following commands are also valid:
1. To increment the gain of channel 1 (in steps of 1), send hex bytes 18 81 80
81. To decrement the gain of channel 1 (in steps of 1), send hex bytes 18 81
81 81.
2. To increment the gain of channel 2 (in steps of 1), send hex bytes 18 82 80
81. To decrement the gain of channel 2 (in steps of 1), send hex bytes 18 82
81 81.
3. To request the gain of channel 1, send hex codes 19 81 80 81. The
response is as per the following tables, except that 59 is sent instead of the
constant byte 16; and 7f instead of the constant byte 3f.
4. To request the gain of channel 2, send hex codes 19 82 80 81.
In the tables below:
•
The dB column shows the machine’s gain value at the setting shown in the
LED column. The VA-4 has a gain resolution of 0.245dB (each step is
0.245dB)
•
Hex codes are shown for channel # 1. For channel # 2, for 4 byte strings
change the 2nd byte from 81 to 82, and for 8 byte strings, change the 6th
byte from 81 to 82.
For example, for gain with the LED showing –166 for channel 2, send 16 82
80 81; for the LED showing 26, send 3f 80 81 81 16 82 c0 81
VA-4 - Protocol 2000
11
