# Presentation: 143752

## DØ High Voltage System Tutorial

**J. Frederick Bartlett**

## Hardware
EPICS Support
HV Record
HV Alarms
Operator GUI Programs
HV Utility Display
Global HV Display
HV Channel Display
Diagnostic Guidelines

Ref:
\\D0server4\projects\Online_Computing\Tutorials\HvTutorial.ppt

**EPICS Support**
**HV Record**
**HV Alarms**
**Operator GUI Programs**
**HV Utility Display**
**Global HV Display**
**HV Channel Display**
**Diagnostic Guidelines**
**Ref:**
**\\D0server4\projects\Online_Computing\Tutorials\HvTutorial.ppt**

**Outline**

## Hardware - HV Crate

**4877**
**Module**

**MVME2301**
**IOC Processor**

## Hardware - HV Module

**Replaceable**
**Generator Pod**

## Hardware - HV Channel

**Voltage**
**Trimpot**

**Voltage**
**Test Point**

## VME crate
6U size
Custom backplane
Additional voltage supplies
+5V Digital, +- 12V Analog, +-12 V Bulk(Unfiltered)
Fermilab/BiRa 4877 module
Cockroft-Walton generator
Six modules per VME crate
8 channels per module
10 voltage generator pod types
Backplane trip links
Backplane module address encoding (geographical)

**6U size**
**Custom backplane**
**Additional voltage supplies**
**+5V Digital, +- 12V Analog, +-12 V Bulk(Unfiltered)**
**Fermilab/BiRa 4877 module**
**Cockroft-Walton generator**
**Six modules per VME crate**
**8 channels per module**
**10 voltage generator pod types**
**Backplane trip links**
**Backplane module address encoding ****(geographical)**

**Hardware**

## Reference
Bi Ra - “Model VME 4877PS High Voltage Power Supply System Manual”

**Bi Ra - “Model VME 4877PS High Voltage Power Supply System Manual”**

**Hardware**

## EPICS High Voltage Support

**HV Support**

## HV Record - hv
High-level device interface
Sequential state machine model (limited implementation of Harel state diagram)
Ramp algorithm
Parabolic end sections
Linear center section
Convergence algorithm
Repeat ramp until within tolerance limit
Enter PAUSE state if repeat limit exceeded

**High-level device interface**
**Sequential state machine model (limited implementation of Harel state diagram)**
**Ramp algorithm**
**Parabolic end sections**
**Linear center section**
**Convergence algorithm**
**Repeat ramp until within tolerance limit**
**Enter PAUSE state if repeat limit exceeded**

**HV Record**

## HV Record

**Purpose**
**Control and monitor an individual HV channel**
**Add high-level operations to a basic voltage generator**
**Implemented as a sequential state machine with states, transitions, actions, and events**
**Ramping to a target voltage is a software function**

## HV Record - Pod Types

## HV Record - State Diagram

**Off**

**On**

**Offline**

**Disabled**

**Average**

**Ramp**

**Holding**

**Tripped**

**Paused**

**Locked**

**Start**

## HV Record - Ramp Algorithm

**Compute average voltage**
**Compute voltage step size and number of steps to reach target voltage**
**Execute ramp steps**
**Compute average voltage**
** ****Compare abs(V****average**** - V****target****) with V****tolerance**
**less or equal - Enter HOLDING state**
**greater - Repeat ramp sequence**

## HV Record - Ramp Algorithm

**If the number of ramp cycles exceeds the limit, enter the PAUSE state and set an alarm condition**

## HV Record – Time Plots

**Decay profile**
**Capacitive load**

## HV Record – Time Plots

**Ramp regions**
**Parabolic ends**
**Linear center**

**Parabolic**
**Region**

**Linear**
**Region**

**Parabolic**
**Region**

## HV Record - Trips

**Channel**
**Overvoltage**
**Trimpot setting**
**Overcurrent**
**Register setting**
**External**
**Backplane connection**
**Module**
**Watchdog**
**Access timeout ****(unused)**
**Interlock**
**Front panel connector ****(unused)**
**External**
**Backplane connection**

## HV Record - Parameters

**ACCL**
**Parabolic acceleration rate (Volts/Sec**2)**
**RATE/ACCL = Duration of parabolic region (Sec)**
**CSCAL**
**Ramping current scaling factor**
**MAXC**
**Current trip level (uAmps)**
**RATE**
**Ramp rate (Volts/Sec)**
**VTOL**
**Voltage setting tolerance**

##  HV Alarms

**Invalid Alarm**
**Hardware access error**
**OFFLINE or INVALID state**
**Minor Alarm**
**OFF or PAUSED states**
**Current warning limit exceeded**
**Voltage warning limit exceeded**
**Major Alarm**
**TRIPPED state**
**Current fatal limit exceeded **
**Voltage fatal limit exceeded**
**A tripped channel will pause the run**

## HV Alarms – SES Display

**Voltage Limit**

**State and Current Limit**

## Operator GUI Programs

**HV Utility display**
**Monitor crate parameters (backplane voltages and temperature)**
**Global HV display**
**Monitor channel state for multiple crates**
**Control state change for multiple crates**
**HV Channel display**
**Monitor channel parameters for a single crate**
**Control state change for single channel or all channels in a crate**

## HV Utility Display

**Paging**
**Tabs**

## HV Utility Display

**Purpose**
**Monitor HV crate parameters**
**Backplane voltages**
**Temperature**
**Properties**
**Organized by detector page**
**Read-only access**
**Background color indicates alarm state**
**Implementation**
**Python script**
**Program name - HvuGui.py**
**Configuration scripts - xxx.hvu**

## Global HV Display

**Left-Click for Crate Display**

**State Change**
**Buttons**

**Channel**
**State**

**Channel**
**Alarm**

**Module**

## Global HV Display

**Purpose**
**Monitor state of channels in multiple crates**
**Execute multiple-crate actions**
**Initiate crate display**
**Properties**
**Organized by crate**
**Multi-crate action buttons**
**Implementation**
**Python script**
**Program name - HvgGui.py**
**Configuration script - xxx.hvg**

## Global HV Display

**Crate button**
**Start individual crate display**
**Action buttons**
**OFF - set channels to OFF state**
**ON - set channels to ON state**
**RESET - reset tripped channels **
**FULL - set to a full (operational) voltage**
**STANDBY – set to standby voltage**

## Global HV Display

**Buttons for other target voltages may be added in the configuration file**
**Channel state colors**
**Purple - OFFLINE, DISABLED**
**Blue - OFF**
**Orange – ON, PAUSED**
**Yellow - AVERAGE, RAMP**
**Green – HOLDING**
**Turquoise – LOCKED**
**Red - TRIPPED**

## HV Channel Display

**Size**
**Control**

**Page Cycle**
**Control**

**Right-Click**
**For Limits**

## HV Channel Display

**Standby Entry**

**State Change**
**Buttons**

**Paging**
**Tabs**

## HV – Channel Display

**HV – Channel Display**

**Channel**
**Stripchart**

**Scale Selection**

**Navigation**
**Buttons**

**Left-Click**
**To Plot Channel**

## HV Channel Display

**Select Voltage Scale**

## HV Channel Display

**Select Current Scale**

## HV Channel Display

**Purpose**
**Monitor individual channels**
**State**
**Voltage and current readback**
**Target voltage**
**Voltage and current trip levels**
**Execute all-channel and individual channel actions**
**Set all-channel and individual channel target voltages**
**Usually displays a single crate**

## HV Channel Display

**Properties**
**Organized by channel**
**Multi-channel action buttons**
**Channel action menu button**
**Implementation**
**Python script**
**Program name - HvcGui.py**
**Configuration script - xxx.hvc**
**Action buttons**
**Similar to global display +**
**OFFLINE/ONLINE**
**PAUSE/RESUME**
**LOCK/UNLOCK**
**Channel state colors**
**Same as Detector display**

## Diagnostic Guidelines

**Channel is in offline state**
**Missing HV module**
**Incorrect module type in database**
**Faulty module**
**Module trips after transition from off to on state**
**After a period with the power off, the channel may not be stable. Leave the power on for ~1/4 hour, after which the channel may recover.**
**Faulty module**

## Diagnostic Guidelines

**Module trips during ramp but has not exceeded either the voltage or current trip limit**
**After a period in the off state, the channel may not be stable. Leave the channel in the on state at zero output for ~1/4 hour, after which the channel may recover**
**Faulty module**

## Diagnostic Guidelines

**Ramp away from zero volts does not converge to target voltage**
**Record tuning parameters set incorrectly**
**Faulty module**
**Current trip during ramp caused by capacitance charging**
**Reduce ramp rate**
**Increase current scaling factor parameter**
**Lengthen parabolic ramp region**

## Diagnostic Guidelines

**Ramp toward zero volts does converges to the target voltage very slowly**
**Reduce load capacitance or increase shunt resistance**
**The Cockroft-Walton generator is a charge pump and can only drive the voltage away from zero (positive or negative). Ramping toward zero requires a shunt resistance to discharge the load capacitance and the voltage divider resistance in the pod is ~10-50 Megohms.**