Information

2. Message from DMM to PC
The general format of the message sent from the DMM to the PC is represented as in the following:
Header Length Msg Type Payload Check Sum
2 Byte 1 Byte 1 Byte TBD 2 Byte
Header:
Header is a two byte value indicating the beginning of the message. For device, the message header is always 0xABCD
regardless of the message type.
Length:
This value represents the length of the message that has to be handled. It is the number of bytes from Msg Type to
the last type of Check Sum.
Msg Type:
This value represents the type of message from the DMM to the PC, where there are 9 types of messages used for the
device, shown as the following table.
Msg Type Value Description
Device ID 0x00 The payload of this message contains the Device ID of the DMM
Live Data 0x01 The payload of this message contains the live of the DMM
Comp Data 0x02 The payload of this message contains the comparison mode setting of the DMM
NOCOMP Data
Transfer
0x03 The payload of this message contains the NOCOMP data that are saved on the memory
COMP Data
Transfer
0x04 The payload of this message contains the COMP data that are saved on the memory
SETUP Data
Transfer
0x05 The payload of this message contains the SETUP data that are saved on the memory
Result 0xFF The payload of this message contains the result of the data transmission for handshaking
purpose.
CheckSum:
16-bits check sum are added after the payload of the message. It is the sum of the byte values from the first byte of
Header to the last byte of Payload.
3.1 Device ID
For the Device ID message, the payload of the message contains the identity number of the DMM on the 20 byte value.
The Device ID is decoded on the PC with ASIC-II character string.
Header Length Msg Type Device ID Check Sum
2 Byte 1 Byte 1 Byte 20 Byte 2 Byte
Msg[0]- Msg[1] Msg[2] Msg[3] Msg[4]-Msg[23] Msg[24]-Msg[25]