RS485 to Optical Converter VME RTM
Project Description
Overview
The CONV-RS485-OPT-RTM (*) is a VME rear transition module providing fiber-optic and electrical inputs and outputs. In combination with the CONV-TTL-RS485 as front-module it provides TTL to optical conversion. The interface with the CONV-TTL-RS485 is through internal RS485 signaling.
The board provides three channels. On the optical side, each channel consists of one input (IN) and two outputs (O1 and O2). Within each channel, the two outputs are driven by the same signal source, using two separate optical transmitters.
The design is based on the following existing modules:
| optical transmitter | CTDAB |
|---|---|
| optical receiver | CTDPR |
(*) Note on project name: After discussion, this was the name selected for the board. It does not comply with other RTM names fron the conv-ttl-xxx family such as the conv-ttl-rtm-blo, conv-ttl-rtm-rs485, conv-ttl-rtm-rs485-db9. Since no TTL signals are involved in this board, the TTL is removed. Furthermore, this board is described first by it's signal interface (RS485 to Toptical), then by the RTM description, in the same way as the conv-ttl-rtm motherboard (without piggyback)
Specifications
| Parameter | Value |
|---|---|
| Number of channels | 3 |
| Optical inputs per channel | 1 |
| Optical outputs per channel | 2 |
| Wavelength | 1310nm |
| Supported fiber type | Single mode |
| Fiber connector | ST |
| Optical power output | ~ 350uW average (~700uW peak) |
| Optical power input | min 8uW average (16uW peak) pulse width distortion effects > 80uW peak |
| Allowed attenuation | max 10dB (10km fiber with 10 connections) |
| Optical signal characteristics | Transmission/ Reception of CERN's GMT signal (500 kHZ DC balanced signal) and of single pulses: Minimum pulse width: 100 ns Maximum frequency: 1 MHz Maximum pulse width: 1 ms Minimum frequency: None, as long as maximum pulse width is respected |
| Latency (μ) | < 250 ns (see also Pulse-Repetition-Performance-Measurements) |
| Jitter (2σ) | <200 ps (see also Pulse-Repetition-Performance-Measurements) |
Versions
| Version | Hardware Design Files |
|---|---|
| 1.1 * | EDA-03760-V1-1 |
| 1.0 | EDA-03760-V1-0 |
Documentation
Project Information
- Design-notes
- Pulse-Repetition-Performance-Measurements
- V1-Schematic-Review
- V1-PCB-Review
- Level Conversion project
- Presentation on level converter boards
- Presentation on design specification
- Production Test Suite
Status
| **** | **** |
|---|---|
| 15-07-2017 | Start working on project. |
| 06-09-2017 | First schematics for a prototype. |
| 27-10-2017 | Prototypes received |
| 06-12-2017 | Prototypes validated |
| 08-12-2017 | Meeting and presentation to discuss design choices and outstanding issues |
| 15-12-2017 | V1-Schematic-Review held at CERN BE-CO-HT |
| 02-02-2018 | V1-PCB-Review held at CERN BE-CO-HT |
| 22-02-2018 | Board moved to production of 5 prototypes |
| 05-04-2018 | 5 v1.0 prototypes have been received. Now to be tested |
| 03-05-2018 | Prototypes validated in the labs. Now being tested in CERN installations |
| 28-06-2018 | Order made for 800 pieces of the FD13R0S1STXS-4BX4 sugar cube transmitters |
| 01-10-2018 | Transmitters received, 120 boards in production |