Connect And Configure The Rs-485 Supplies; To Set Up An Rs-485 Chain; Multi-Drop Programming Using Scpi Commands; Selecting One Power Supply In A Multi-Drop Chain - TDK-Lambda Z+ series User Manual

11.3 Connect and Configure the RS-485 Supplies

The RS-485 linked power supplies are called the Slave supplies. They may be individually commanded
and queried using the LAN port on the Master supply.

11.3.1 To Set Up an RS-485 Chain

A. Set the supply into RS-485 mode as described in section 3.1.2
B. Connect the RS-485 Link Cables from the master's J4-OUT to the slave's J4-IN
C. Power-up the supplies
D. Set the supply's RS-485 address as described in section 11.2.2.
E. Press "REM" button. Move Voltage encoder until "baud" appears on the display. Press the
Voltage encoder. Then rotate Current encoder to 57.6 and press Current encoder to select.

11.4 Multi-drop Programming Using SCPI Commands

11.4.1 Selecting One Power Supply in a Multi-drop Chain

All the SCPI commands may be sent to any one of the supplies in an RS-485 chain by first sending
the INST:nSEL address command. All commands and queries will then apply only to the selected
supply, until a new INST:nSEL is sent.
At power-up, the LAN master supply is automatically the one selected.
After sending INST:nSEL, it is recommended that you verify the command by sending INST:nSEL?
or SYST:ERR?, otherwise further commands may go to the wrong power supply.

11.4.2 Global Commands in a Multi-drop Chain

The GLOBAL commands affect all of the chained supplies at the same time, including the LAN
supply.
•
There is no SYSTEM:ERROR? response message if one or more supplies cannot execute a
global command.
•
It is required that the user's application adds a 20 millisecond delay after initiating a global
command, and before sending any other messages. This is because there is no feedback from
the multi-drop chain to indicate the command is suntil being processed.
•
There is no query version of these commands. Global settings must be queried by selecting
one power supply and reading it's setting.
•
The error and status registers operate differently.
•
The global commands are not SCPI compliant.
The global commands do not affect which power supply has been selected using the INST:nSEL
command. For example, if the following commands are sent:
INST:nSEL 4
:VOLT 50
GLOB:VOLT 70
(wait 20 mSec)
:VOLT 90
Then all the supplies on the multi-drop chain will be set to 70 volts except the supply at RS-485
address 4 will be set to 90 volts (after the global command, further INST:nSEL is not required).
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