Ulvac DC-5-P, Operation Manual

Page: 89 / 105

DC Puse Power Supply
【
DC-5-P/DC-10-P
】 8 APPENDIX
77
Table 8-2 Message packet
Header Field Command field Data field Checksum
2byte
・
SOF
・
Address
・
Data length information
1byte
0x00
～
0xFF
0
～
7byte
Data transmitted in relation to the
command.
The length depends on the
command.
1 byte
XOR values of all data until
just before.
● Header
A header field has four data types. A header consists of a data length of two bytes in total. The first one bit
is SOF, the following seven bits are NET Address, and the last eight bits are information on the data field
length, respectively.
Details on each data included in a header are described below.
○ SOF(Start of frame)
：
This is a specific bit patter which indicates the start of frame.
SOF is 1 bit and, when the bit takes 1 in DC, the frame starts from there and the
following Address is analyzed.
○ NET Address
：
The Address signal is 7 bits.
For the Address settings in DC, see the IP Address Settings section.
The settable Address range is from Nos. 1 to 127.
Only the unit in which this Address matches that set in DC establishes
communication.
* Also for the RS232C communication, the Address set in DC needs to be transmitted.
○ Data field length
：
The total number of bytes of the c the data is transmitted.
The commands themselves are all 1 byte but the following data are 0 to 7 bytes
depending on the command.
The allocation is as follows.
0: 1 byte (command only)
1: 2 byte (c 1-byte data length)
2: 3 byte
(c 2-byte data length)
・
・
7: 8 byte (c 7-byte data length)
For the data length by command, see the command list to be described later.
● Command
The command field consists of 1-byte values (0x00 to 0xFF). The command type consists of Write and
Read.
The Write command changes parameter set values or executes each operation.
The Read command requires data or status information.
● Data
The data field is a field for transmitting data to complement each command. For the commands with which
data needs to be transmitted, the data needs to be transmitted following the command. The data length is
up to 7 bytes and 8 byte in total together with the command.
In some cases, data does not need to be received depending on the command, resulting in a data length of
0 byte (no values included).
Based on the data length information included in the header field, DC estimates the data length to be
transmitted.
For details on data, see the command list to be described later.