The LWDAQ Union provides two RJ-45 sockets to join LWDAQ or Ethernet cables. The A2039A provides a patch area where we can connect to the eight signals, attach pull-up and pull-down resistors, and cut the signal connections with a scalpel.
The A2039B is a compact union designed for extending cables that turn out to be too short during LWDAQ system installation. The A2039B comes with two shielded sockets and is enclosed in insulating heat shrink. It is loaded with two shielded connectors with their shields wired together so that the shield of the joined cables will be continuous.
The A3039E is a six-way union with one side shielded connectors and the other side unshielded. The shielded connectors are on the front side and are to receive cables on their way from the LWDAQ driver. The unshielded connectors are on the back side, and are for cables that run to LWDAQ devices, multiplexers, repeaters, or further unions
The six shields of the front-side sockets on the A2039E are connected together and to the chassis, if the chassis is present. The A2039E is designed to take part in star grounding, which is the standard for the long-wire data acquisition system (LWDAQ). The back-side sockets are unshielded. The shields of the cables plugged into the back side will be grounded at their far ends. The star grounding arrangement prevents alternating magnetic fields from generating ground loop currents in the cable shields.
Note: All our schematics and Gerber files are distributed for free under the GNU General Public License.A203901A: Gerber files for A203901A circuit board used in A2039A.