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en:wiring

Cabling

About the Cable Network

The satellite depends on its cable network for information exchange between subsystems and the central computer as well as powering its subsystems. Satellite subsystems are provided with two redundant connectors for the orbiter network. In that manner, a device connected to the onboard network will not only be itself accessible for communication but will also enable daisy-chain connections to subsequent components in the circuit. The data exchange network is based on a bus architecture using RS-485 serial interfaces. Power and data network lines are combined into a single ribbon cable to facilitate assembly. Subsystems are connected using a DB-9F (female) connector on the harness side and a DB-9M (male) connector on the device side. Considering that components of the construction set can be arranged in different ways, sizing and making individual ribbon cables of necessary lengths and configurations will be left to the user.

Preparations

  • Take the following items out of the Orbicraft kit: crimper, wire-cutters, ribbon cable spool, 2 female connectors, ribbon cable tester and 12VDC power adapter;
  • Cut a ribbon cable of required length from the 9-channel ribbon cable spool.

Ribbon Cable Assembly

  • Insert a yellow fixture from the kit into the crimper;
  • Place the connector into the yellow fixture below the clamping bar of the crimper;
  • Holding the crimper with the connector with one hand, insert cable end into the crimper with your other hand;
  • Compress the connector with cable end inserted until the crimper makes a distinct click;
  • Perform a visual check to make sure that the connector has clicked into place.
Take care to ensure that the ribbon cable has fully entered the connector but does not protrude too far from its back side.
Before applying force to the crimper to click, press the latch gently to make sure that cable wires fit evenly between contact pins and only then finally click the connector into place.
  • Repeat the same operations with the opposite end of the ribbon cable having the second female connector.
When crimping the cable, remember that all connectors must be facing the same side, as shown in pictures below.

Correct assembly:

Wrong assembly:

The current connector pinout (designations of individual pins) minimizes the likelihood of damage of the equipment if the user fails to terminate the ribbon cable correctly. Nevertheless it provides no guarantee that the device cannot be damaged at all. It should also be noted that ribbon cables can be made and tailored by the user without any need for special knowledge and tools. All devices in the network can be connected both in series using point-to-point cables (as shown in the figure below) or branched using ribbon cables with more than two connectors.

The male-male camera cable may not be longer than 40 cm.
Never mix orbiter devices with devices not designed for “orbital” operation (the “terrestrial” HF receiver and the “terrestrial” VHF/UHF receiver) in the same cable circuit. Take special care to avoid mixing the USB-RS485 surface segment cable and the orbiter power system (OPS) in the same cable network. Failure to do so may result in damage to components of the construction set.

Ribbon Cable Test

  • Connect the ribbon cable tester to the 220 VAC mains using a 12 VDC adapter from the set;
  • Insert the assembled ribbon cable into the respective receptacles of the cable tester. The “OK” green LED will light up.
If the “Open Circuit” yellow LED remains lit, there is a discontinuity in the circuit. Poorly crimped ribbon cable is the most likely reason.
If the “Short Circuit” red LED lights up, this may be caused either by punctured insulation of two adjacent channels during cable crimping or by improper orientation of two connectors against each other. Try to crimp the cable again following instructions above.
en/wiring.txt · Last modified: 2020/01/20 12:36 by golikov