Pmbus Command Set; Operation (On/Off); Commands To Read Inventory Details - TDK-Lambda HFE2500 Series Instruction Manual

4. PMBus COMMAND SET

The interval between two consecutive commands to the power supply should be at least 25ms to ensure proper monitoring
fuctunality
4.1 READ_STATUS
This Command is used to read the status of the Power Supply. The Status information is stored in a special register called the "STATUS REGISTER".
The PMBUS reads 8 different types of Faults and Warnings.
Command Used
Fault is indicated by "1". No fault is indicated by "0".
For Example: If DC Fail occurs, READ_STATUS will return 01h. SMBALERT will go "LOW"
If AC Fail occurs, READ_STATUS will return 11h. SMBALERT will go "LOW"
Faults
DC Fail
Over Temperature Protection FAULT
Over Temperature Alarm
Fan Fail
AC Fail
Over Voltage Protection
Programmed Voltage
more than allowed
Command Error
(*1) If Max Allowed Voltage is set to 48V and Programmed Voltage is set to 50V, Output will be programmed to 48V, Bit No 6 will be
"1", and SMBALERT will become "LOW".
(*2) If any Command sent is not understood by the Supply, bit no 7 will be "1" and SMBALERT will become "LOW".
4.2 CLEAR_FAULTS
This command is used to clear the "STATUS REGISTER" after any fault occurs.
If the CLEAR_FAULTS command is not sent after any fault occurs, the "STATUS REGISTER" will not be cleared.
SMBALERT signal will remain "LOW" until a "CLEAR_FAULTS" command is sent.
If a Fault or Warning is still present after "CLEAR_FAULTS" is sent, "STATUS REGISTER" will be updated and the SMBALERT signal will be "LOW" again.
Command code

4.3 OPERATION (ON/OFF)

Command code
If the Power Supply is turned OFF with the "OPERATION OFF" command, the Supply can be turned ON
with the "OPERATION ON" command only. Inhibit and Enable signals are disabled.

4.4 COMMANDS TO READ INVENTORY DETAILS

Command Name
PMBUS_REVISION
MFR_ID
MFR_MODEL
MFR_OUTPUT
MFR_REVISION
MFR_LOCATION
MFR_DATE
MFR_SERIAL
All details except for ‹PMBUS_REVISION› are stored in ASCII format.
D0h
Type Bit No in Meaning
Status
Register
FAULT 0 Output Voltage < 85~95% of Set Vout
1 Internal temperature higher than safe limit
WARNING 2 Internal temperature ~ 10°C below safe limit. Output ON
FAULT 3 One or both Fans are not working
FAULT 4 Input Voltage <85Vac / >270Vac
FAULT 5 Output Voltage > 1.15xVset
WARNING 6 Programmed Voltage more than Max
Allowed Voltage (*1)
WARNING 7 Command not understood by Power Supply (*2) Output ON
03h
01h
01h
Command code
98h
99h
9Ah
D1h
9Bh
9Ch
9Dh
9Eh
Type
Read Byte
Type
Send Byte
Type
R/W Byte
R/W Byte
Type
Read Byte
Read Block
Read Block
Read Block
Read Block
Read Block
Read Block
Read Block
16
#Data bytes
1
Main output behavior
Output OFF/Output Low
Output OFF
Output OFF
Output OFF/Output ON
Output OFF
Output ON
#Data bytes
0
Data sent
00h=OFF
80h=ON
#Data bytes
1
16
16
16
16
16
16
20