It's probably the easiest way.
You can download Hidiscovery from the Hirschmann Website :
http://www.hirschmann.com/en/Hirschmann_Produkte/Industrial_Ethernet/Software/Software_Tools/HiDiscovery/index.phtml
Hidiscovery is also included in the CD delivered with each product.
Connect your laptop with Hidiscovery and the BATs devices to the same L2 network
Start Hidiscovery.
Hidiscovery may find automatically the Hirschmann devices connected to your L2 network. But if you have several network adapaters it could also occur that Hidiscovery starts using a wrong Network adapter. In this case, select the relevant network adapter (1) and Rescann the network (2).
From the discovered devices double clic on the one you want to configure an IP address (3)
A new window will open wher you can enter Name and IP settings for the device.
By clicking OK the settings you entered are automatically applied on the device.

By default, DHCP is enabled on the WLC and on the Open BAT.
It's then possible t dynamically assign an IP address to the device.
An Hirschmann switch can be used as DHCP server or you can download free DHCP servers on Internet.
One of the easiest and widely used id TFTPD32 which can be downloaded here : http://tftpd32.jounin.net/tftpd32_download.html
The following example was done with tftpd64 v4.50 on windows 7

Clic on settings
Go in the DHCP Tab
Enter your DHCP pool, subnet mask, Gateway if necessary
Then OK. The configuration of your DHCP server is finished.
NB: UDP port 67 is used by the server. Take care that your Firewall don't block it
(allow incoming trafic with port destination 67, outgoing trafic with port destination 68)

At the next DHCP request from the device, your DHCP server will automatically attribute to teh device an IP address from the defined pool of addresses.

WLC and Open BAT have a V24 interface (A coded M12 plug)
A cable is delevered with each device (M12 - RS232) making possible serial connection between a workstation with serial interface (RS232) and the WLC or Open BAT.
If the workstation doesn't have any serial interface, converters USB to serial are needed.

PuTTY is an SSH and telnet client but it can also be used as VT100 Terminal emulation.
You can download Putty here: http://www.putty.org/

In our example. we use a USB to serial adapter (Prolific).
To check which COM port is in use, go in:
Control Panel > Administrative Tools > Computer Management > Device Manager > Ports (COM & LPT)
In our example it corresponds to COM5

1/ Select the connection Type: Serial
2/ Enter the VT100 Speed: 115200
3/ Enter the serial line in use: in our example COM5
4/ Open

After a succesfull login (default password: private) only 1 command is enough to set an IP address:
set Setup/TCP-IP/Network-list/intranet IP_ADDRESS MASK

LANconfig is a management software for Open BAT devices and controllers.
You can install it directly from the CD delivered with each device or download it from the Hirschmann Website.

Pre-requisite for the first steps:
The workstation with LANconfig and the device to configure must be in the same L2 network.
This example is based on the assumption that the device to configure has factory settings.

1/ Search for devices in the network pressing the ""find devices"" button (1)
2/ In the ""Find Devices"" menu, select ""Search the local network"". It will search for the BAT and WLC connected in the same L2 network as all your network interfaces (if you have 2 network interfaces in 2 different L2 networks, the discovery will be done in the 2 L2 networks)
3/ Don't forget to tick ""Extended search to managed APs"", otherwise Open BAT with default config won't be find.

Devices present will be find, new ones (without IP address) or already configured ones.
Select the ""new"" devices and select ""Add selected devices""

In the main Window the devices without configuration appear with this icon..
Automatically a Wizard is launched. Follow the Wizard.

Default password : private

1/ Give the Device a Name
2/ Give the device a password
3/ Configure the SNMP read only community
4/ Configure the DHCP Mode (on our example off)

1/ Give the device an IP address
2/ Give the device Time settings
3/ Optionnal settings (Location ...)
4/ Finish