WAGO 750 Series User Manual

Bootloader (U-Boot) • 189
Environment Variables
WAGO-I/O-SYSTEM 750
Linux Fieldbus Coupler
9.5 Environment Variables
A list of all environment variables set can be viewed using
> printenv.
An environment variable can contain values, further environment variables or
U-Boot commands. In the latter case, the environment variable works similar
to a macro which processes the commands one after the other.
The relevant environment variables for the Linux fieldbus coupler boot
process are:
• ipmode
Defines the type of IP configuration. Possible values are bootp, dhcp, a
static IP in the format xxx.xxx.xxx.xxx or a completely static
configuration in the format
<FBK-IP>:<ServerIP>:<GW-IP>:<Netmask>:<Hostname>:<Device>
10.1.1.8:10.1.2:1:10.1.1.254:255.255.255.0:lfbk:eth0
• bootargs
Contains further parameters for the kernel, for example the root file system
(root=/dev/mtdblock3)
• bootcmd
Contains a macro that creates a kernel command line from ipmode and
bootargs and starts the kernel. This macro is called automatically 3
seconds after starting the Linux fieldbus coupler (stored in the bootdelay
variable).
• bootA/bootB
Macros that, depending on the selector switch position of the Linux
fieldbus coupler, are copied to bootcmd when U-Boot is started.
•
bootdelay
The time the system waits for the abort password to arrrive
•
ethaddr
MAC address of the Linux fieldbus coupler

WAGO 750 Series Specifications

General

Protection Class	IP20
Bus Couplers	PROFIBUS, CANopen, Ethernet
Modules	Digital Input, Digital Output, Analog Input, Analog Output
Mounting	DIN rail mounting
Voltage Supply	24 V DC (typical)
Communication Protocol	Depends on the bus coupler (e.g., PROFIBUS, CANopen, DeviceNet, Ethernet)
Digital Input Channels	Varies by module (e.g., 8, 16 channels)
Digital Output Channels	Varies by module (e.g., 8, 16 channels)
Analog Input Channels	Varies by module (e.g., 2, 4, 8 channels)
Analog Output Channels	1, 2, 4 channels (depending on module)
Width	12 mm, 24 mm (typical module widths)
Number of Channels	Varies by module type
Current Consumption per Channel	Varies by module type