Installation and Configuration
Configure for Multichannel Operation
Release 2.1 35
Configure for Multichannel Operation
Multichannel
Connections
You may remotely control up to 50 power supplies from one GPIB interface by using
multichannel addressing via the CANbus.
One power supply will be connected to a PC via GPIB. All other power supplies are
connected via CANbus (Controller Area Network) to that unit. SCPI commands that
include a channel address will be sent via the CANbus to the other power supplies.
(Commands with the local address will be executed locally and will not be sent).
The multichannel address must be appended to the program mnemonic. If no
multichannel address is appended to the program mnemonic, the command is
executed by the local (directly connected) power supply.
Each unit of the network can send and receive commands to and from other units on
the network. It is highly recommended that only one command be sent at a time. Any
GPIB timeout settings should be increased when using multichannel commands.
Multichannel
Configuration
If a second power supply that has the same multichannel address as another is
connected to the bus, it will automatically increment its address until it finds a unique
address. If it fails to find a unique address, it will disconnect itself from the bus and
you will not be able to communicate with it until you disconnect the other power
supplies and cycle the power. Therefore, when configuring a network of supplies,
you can make all connections, and power on one supply at a time. They will
configure their addresses in the order that they were powered on. Be sure to note the
address of each power supply for future reference or in case you want to reorganize
the network.
Example:
Connect 3 power supplies for multichannel operation. You have one GPIB-M supply
and 2 CAN-only supplies. The GPIB-M supply's multichannel address is set to 1 at
the factory. Both CAN-only supplies are set to 2.
Connect all units as described in “Basic Setup Procedure” on page 31.
Power on the GPIB-M supply, then one of the CAN-only supplies. Check that you
can communicate with both. Send the *IDN? query to return the identification string
from the GPIB-M supply. Send "SYST2:IDEN?" to return the ID string from the
CAN-only unit.
Power on the last unit. Since multichannel address 2 already exists on the bus, it will
automatically configure itself to address 3. Check that this is the case by sending the
command "SYST3:IDEN?"