NRAO Home  >  Green Bank  |  Wiki Topic:    GB > Software > ModificationRequest4C505

Changes | Index | Contents | Search | Statistics | Go

Converter Rack: Add Ability to Set Power Levels and to Balance to those Levels

• 1. Introduction
• 2. Background
• 3. Requirements
• 4. Design
  • 4.1 config tool
  • 4.2 Balancing API
  • 4.3 Turtle
• 3. Requirements
• 4. Design
  • 4.1 Balancing API
  • 4.2 Turtle
• 5. Deployment Checklist
• 6. Test Plan
  • 6.1 Internal Testing
  • 6.2 Sponsor Testing
  • 6.3 Integration/Regression Tests
• Signatures
• CCC Discussion Area

1. Introduction

Currently, several GBT devices have the ability for the observer to readily set the target power levels and have the software automatically adjust the relevent attenuators to achieve those power levels within a given error. The focus of this MR is to implement a Converter Rack balancing function within the Balancing API.

2. Background

During the discussion of this MR with RogerNorrod, he commented that the Converter Rack detectors [samplers] are not much use, except for rough indication. The problem with the power detectors is being solved by designing new detectors which will have a wider dynamic range. For the present detectors the relation between detector reading in volts and power level in db is approximately:

change in db = 10 log (ratio of voltage readings)

For the new detectors, the factor will probably be 40 instead of 10. The exact relation will be provided (quite soon I hope). MelindaMello I think some of these have been changed already? We need the equation for these as well as the Converter Rack numbers that have already been converted. If there is a mix of old/new converter modules, we should consider a mapping configuration file that the Balance API will use so that when Steve White upgrades more converter modules, the Balance API automatically uses the correct equation We should consider implementing this before the new samplers are available, with the understanding that the criteria for balancing will change and that thorough testing is not possible until the new samplers are installed.

This MR is part of a series of MRs aimed at creating a production Balancing API in Python. For more information regarding this effort, please refer to the BalancingMetaMR.

3. Requirements

• The observer needs to be able to balance to a preset value (as is done in e.g. the IF Rack).
• The preset values may differ for different converter modules.
• Individual converter modules must have a user specified mechanism that indicates whether it should be balanced and what the target level is.
• Inputs include:
  • array of target values
  • array of balance enable flags.
  • a balance tolerance (default will be 0.5 dB)
• The target values, balance enables, and tolerance may be set by the config tool; MelindaMello -- If the Converter Rack balance is done internal to the Balance API then there are no "balance enables" in the Ygor Manager to set.
• Target values will depend on the backend, hence the config tool can set defaults or use a user-supplied keyword to get the values.
• All features for this MR should be accessible both inside an observing script and also as a command which can be run during a scan (as is currently possible with other balance commands).
• The criteria for warning messages will be in a configuration file.
• If cannot balance within the specified tolerance, issue warning message.
• If power is too low, set attenuator to zero, issue warning message.
• If power is too high, set attenuator to max, issue warning.

• RFI -- balancing in the presence of RFI will be implemented as described in 11C505.
• Cal on/off - balancing with the Noise Cal on or off will be implemented as described in 12C505.
• The Balancing API should allow the possibility of Converter Rack balancing being a standard part of the default balancing sequence. This applies only to certain observing setups, for example VLBI, and pulsar observing.

4. Design

4.1 config tool

• Add another keyword for converter module target values.
• Change code to set converter module target values based on new keyword or the default.
• Add setting the converter module balance enables.
• Add setting converter module tolerance values.

4.2 Balancing API

• Add Converter Rack, "cfr", as a device option.

4.3 Turtle

• Add Converter Rack, "cfr", as a device option.

Main.Melinda This is how I suggest sections 3 and 4 should read

3. Requirements

5. Deployment Checklist

What has to get done to integrate this completely into the system. This checklist must be completed before Cycle Integration Testing begins.

• Communication with Computing group needed?
• What documentation needs to be updated?
• Training Needed? Is this being released to staff astronomers or everyone right now?
• Notification Needed?

6. Test Plan

Critical!! ChangeControlCommittee will be reviewing these.

Don't forget to include/acquire any additional GBT test time needed outside integration/regression testing! Get your requests in early!

Important! If possible, you should conduct as many of your tests as possible in offline modes and/or with a simulator. We should constantly endeavor to minimize our use of telescope time for testing!

6.1 Internal Testing

This section covers things like unit testing, simulator testing, and any other tests required to make sure this MR is ready for sponsor/integration/regression testing.

6.2 Sponsor Testing

• Test balancing with target values, balance enables, and tolerances set to a variety of different values.
• Test RFI and cal on/off options.

6.3 Integration/Regression Tests

What do the integration/regression testers need to do in order to test this MR.

Signatures

APPROVED: I acknowledge that my request is fully contained in this MR, and if the SDD delivers exactly what I specified, I will be happy.

ACCEPTED: I acknowledge that I have validated the completed code according to the acceptance tests, and I am happy with the results.

Written	Name - date
Approved/Signed by Sponsor	Name - date
Approved/Signed by CCC	symbol - date
Accepted/Delivered	Name - date

Symbols:

• Use %X% if MR is not complete (will display )
• Use %Y% if MR is complete (will display )

CCC Discussion Area