TDK 750W HALF RACK technical manual Single Byte Commands, Enable MD Mode MD Mode Option Required

7.10 SINGLE BYTE COMMANDS

7.10.1 General

Single byte commands are commands in which all the necessary data for the supply to act upon is contained in a single byte. Single byte commands will be executed immediately by the supply. If the command requires data to be sent to the HOST PC or IEEE Board (see sections 7.10.4 and 7.10.3.1) that response will be transmitted immediately with no delay due to any software overhead. With the exception of the Disconnect from communications command, section 7.10.3.1, commands must be sent by the HOST PC or IEEE Board 2 times in sequence for verifi- cation. Alll have the most significant bit, D7, set to a logic 1. A CR, carriage return, character is not included in a single byte command. The RST command will not change any setting made by a single byte command.

All Single Byte commands will be executed in 1 ms or less. This does not include any response sent to the HOST/IEEE Board, which is dependent upon the response length and the serial transmission speed (Baud rate).

7.10.2 Global commands without response

7.10.2.1Disable MD Mode (MD MODE OPTION REQUIRED)

Disable is the default condition upon power up. The Hex value of the command is 0xA0. Send it two times in sequence. All supplies, both the currently addressed supply and all non-addressed supplies, will disable MD Mode as a result of this command.

7.10.2.2Enable MD Mode (MD MODE OPTION REQUIRED)

Send to enable Multi Drop Mode. The Hex value of the command is 0xA1. Sent it two times in sequence. When this command is sent, the supply will set SRQ retransmission to the disable state; if you wish it to be enabled you must send the enable command. All supplies, both the cur- rently addressed supply and all non-addressed supplies, will enable MD Mode as a result of this command.

7.10.2.3Disable SRQ retransmission (MD MODE OPTION REQUIRED)

Disable is the default condition upon power up. The Hex value of the command is 0xA2. Sent it two times in sequence. If the supply sends an SRQ it will only sent it 1 time. All supplies, both the currently addressed supply and all non-addressed supplies, will disable SRQ retransmission as a result of this command. All status registers will retain their data when this command is sent.

7.10.2.4Enable SRQ retransmission (MD MODE OPTION REQUIRED)

Enable retransmission of SRQs. This is only available when the Multi Drop Mode is enabled in the supply. The Hex value of the command is 0xA3. Send it two times in sequence. If the supply sends an SRQ it will be repeated on a timely basis, 10 ms plus 20 ms times the supply address, until answered. All supplies, both the currently addressed supply and all non-addressed supplies, will enable SRQ retransmission as a result of this command.

7.10.2.5Enable FLT Bit in the SENA Register

The Hex value of the command is 0xA4. Send it two times in sequence.

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83-507-5002 Rev. B