VMR-DIO-24CH-DCI project
Project Description
Background
The aim of this project is to distribute dry contact input signal states
across a wide geographical area, using an Ethernet-based White Rabbit
(WR) network.
Hardware with a set number of input channels (24 channels , but this may
still change), will be used to acquire the input signals, and then
transmit these to
operators.
Main Requirements
- Each input signal is in fact the state of a dry contact switch that arrives via a LEMO 2-pin connector and a wire from the hardware source.
- The new system should adopt a more distributed architecture so as to provide several logging points. Emphasis will be on reducing length of transmission lines between the dry contact switches and the acquisition points.
- A number of signal states are collected at different network nodes. Communication between these acquisition points and the central systems will be handled by the White Rabbit switch.
- The hardware systems involved need to be robust and highly reliable. However, since these are prone to human error and equipment failure, means of diagnosis should be available, perhaps also to prevent such failures even before they occur (?).
- The new patch panel will have to be designed with some mechanical constraints in mind, i.e. allowing enough room for manual plugging/unplugging and preferably with individual labelling/numbering and LED indicator (or other method) for quick visual diagnosis of each condition.
Proposed system
A block diagram of the proposed system is shown above.
- Most of the new hardware components will be added in the form of a new purpose-built rear transition module or RTM, to be designed as part of the hardware project.
- The RTM will be connected through the VMC P2 port to the SVEC board. The gateware required for the RTM-SVEC communication is developed in the gateware project
- 24 channels will be provided for dry contact switches acquision. They will be transmitted via long wires plugged on the RTM panel using 2-pin LEMO connectors.
- The RTM panel should include some means for visual (LED) diagnosis of the on-off states of dry contact inputs (DCIs).
- As the system will be used for transmission of (sometimes) critical switch signals and control operations, a robust fail safe mode needs to be put in place. For example, in the case of unexpected power loss in the VME crate, the rest of the system should be informed.
- The RTM-SVEC combination communicates with a White Rabbit switch using the SFP connector.
- More gateware should be written to handle communication with WR both on the transmit and the receive side.
Project Information
This project is divided into three separate projects:
Useful user documentation can be found at these locations:
Status
Date | Event |
2011 | Initial discussions about replacing the external conditions system |
01-10-2015 | Start working on project. |
05-11-2015 | OHWR project page created. |
Denia Bouhired-Ferrag - Erik van der Bij - 12 Novembre 2015