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When the Ethernet option is fitted to the unit the user cannot change between RS232 or RS485, or baud
rate, however the address can still be changed. Changing the baud rate, which by default is 19200 on an
Ethernet enabled, unit will stop the Ethernet working properly!
MESSAGE FORMAT
The unit transmits and receives data serially in an asynchronous format using the standard ASCII character
set. The serial data consists of message frames composed of the following message characters: STX,
BYTE COUNT, DEVICE ADDRESS, INSTRUCTION, BODY, CHECKSUM, ETX. All characters are
compulsory except for the message body. The presence of a message body is determined by the message
type (INSTRUCTION). The total number of message characters in a message frame may range from a
minimum of 6 to a maximum of 255.
The remote control follows the following protocol: (in byte form)
[STX] start of message character #02.
[B]
char defining how many characters are in the message including the STX & ETX parts.
[A]
Address of unit. Address ranges from ASCI character 32 to 47. (configurable via dip switches
- see earlier
[I]
Instruction number.
See table below.
[MESSAGE]
numerous characters from length 0 upwards. If no message present enter a 0.
[CHKSUM]
The checksum is used to verify the accuracy of the message frame. The checksum is defined as
the summation of all the bytes in the message, beginning with the 3rd byte (DEVICE
ADDRESS) and extending through the body of the message, ending with the last byte before the
checksum. The total of the bytes is then ANDed with 255 so that the checksum is truncated to a
single byte.
[ETX] End of transmission character #03
All message to and from the unit follow the above protocol with a character format of 8 data bits, one
stop bit, no parity, baud rate 300, 2400, 9600 or 19200. Note that all numeric values are shown as decimal.
Message Information
The message protocol for this unit has been made to emulate the RCU100 units therefore the bands are
set as 'A' and 'B' not '1' and '2' as the metalwork/front panel says. Extra information has been added
to show the PSU status information.
Instruction Number List: (in decimal):
To DLA200 unit
32
34
36
Issue 1.15
From DLA200 unit
33
37
DLA200 Dual Line Amplifier Unit
Description
Status request
Status reply
Configure unit
Extended block status request
Extended block status reply
Page 9
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