TDK-Lambda GH10-100 - Checksum; Data Format; End of Command; SCPI Protocol

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4.12 SCPI Protocol
Recommended time delay between commands: 5mSec minimum. Some commands might require
longer time. In such cases, refer to NOTE following command description.
NOTE
Selecting the power supply (INSTrument:NSELect <address>) is necessary before using any
other command.
4.12.1 Data Format
Serial data format is 8 bit, one start bit and one stop bit. No parity bit.
4.12.2 End of Command
The end of command is the Carriage Return character (ASCII 13, 0x0D) and/or the Line Feed
(ASCII 10, 0x0A) character.
4.12.3 Checksum
The user may optionally add a checksum to the end of the command. The checksum is ”$”followed
by two hex characters. If a command or a query has checksum, the response will also have one.
There is no CR between the command string and the ”$” sign. Example: STT?$3A, STAT?$7B.
STT?$3A checksum is calculated as follows: S = 0x53, T = 0x54, T = 0x54, ? = 0x3F.
0x53 + 0x54 + 0x54 + 0x3F = 0x013A, checksum is the least significant byte – 0x3A.
STAT?$7B checksum is calculated as follows: S = 0x53, T = 0x54, A = 0x41, T = 0x54, ? = 0x3F.
0x53 + 0x54 + 0x41 + 0x54 + 0x3F = 0X017B, checksum is the least significant byte – 0x7B.
4.12.4 SCPI Requirements
The power supply conforms to the following SCPI requirements:
• SCPI common commands.
• SCPI Command Tree.
• Subsystem commands.
• The ROOT level.
• The power supply is powered On.
• A device clear (DCL) is sent to the power supply.
• The SCPI interface encounters a root specifier (:).
• Questionable Status Register (QSR), Condition, Event, Enable.
• Operation Status Register (OSR), Condition, Event, Enable.
• Status Byte Register (SBR).
• Standard Event Status Register (SESR).
• MIN and MAX Parameters.
• Suffix and Multipliers.
• Boolean data. 0|1 or OFF|ON.