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Overview

The Maintenance module tracks preventive and corrective maintenance performed on equipment deployed at project sites. Each maintenance operation generates a SheetMaintenance record that documents the work performed, parts replaced, and costs incurred.

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SheetMaintenance Model

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Core Purpose

A maintenance sheet documents a single maintenance intervention:
  • Preventive: Scheduled maintenance based on frequency settings
  • Corrective: Repairs triggered by equipment failures
class SheetMaintenance(BaseModel):
    id = AutoField(primary_key=True)
    id_sheet_project = ForeignKey(SheetProject, on_delete=PROTECT)
    sheet_number = PositiveBigIntegerField(unique=True)  # Auto-generated
    status = CharField(
        choices=[
            ('DRAFT', 'BORRADOR'),
            ('CLOSED', 'EN PLANILLA'),
            ('VOID', 'ANULADO')
        ],
        default='DRAFT'
    )
    maintenance_type = CharField(
        choices=[
            ('PREVENTIVO', 'PREVENTIVO'),
            ('CORRECTIVO', 'CORRECTIVO')
        ],
        default='PREVENTIVO'
    )
    resource_item = ForeignKey(ResourceItem, on_delete=PROTECT)
    responsible_technical = ForeignKey(Technical, on_delete=PROTECT)

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Sheet Numbering

Maintenance sheets use automatic global sequential numbering: 
# Auto-generated on save
sheet_number = 1, 2, 3, 4...  # Never resets
Unlike custody chains (which use 7-digit strings), maintenance sheet numbers are plain integers that increment globally across all projects.

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Maintenance Types

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Preventive Maintenance

PREVENTIVO

Scheduled maintenance based on ProjectResourceItem frequency settings:
  • DAY: Every N days (interval_days)
  • WEEK: Specific weekdays (weekdays)
  • MONTH: Specific month days (monthdays)
Frequency Examples: 
# Daily interval: Maintenance every 2 days
frequency_type = 'DAY'
interval_days = 2

# Weekly schedule: Monday, Wednesday, Friday
frequency_type = 'WEEK'
weekdays = [0, 2, 4]  # 0=Monday, 6=Sunday

# Monthly schedule: 1st and 15th of month
frequency_type = 'MONTH'
monthdays = [1, 15]

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Corrective Maintenance

CORRECTIVO

Unscheduled repairs triggered by:
  • Equipment failures
  • Damage reports
  • Client requests
  • Safety issues

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Maintenance Details

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Work Information

requested_by = CharField(max_length=255)  # Who requested the maintenance
rig = CharField(max_length=50)  # RIG identifier at client site
code = CharField(max_length=100)  # Equipment code
location = CharField(max_length=255)  # Specific location
start_date = DateField()
end_date = DateField()
total_days = PositiveIntegerField()  # Duration in days

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Cost Tracking

cost_day = DecimalField(max_digits=10, decimal_places=2)  # Daily rate
cost_total = DecimalField(max_digits=10, decimal_places=2)  # Total cost
cost_logistics = DecimalField(max_digits=10, decimal_places=2)  # Transport cost
Cost Calculation: 
cost_total = total_days * cost_day
# Logistics cost is added separately

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Work Order Integration

Maintenance sheets are linked to work orders for billing: 
sheet_project_maintenance_concept = CharField(
    max_length=255,
    default="SERVICIO TÉCNICO ESPECIALIZADO"
)
sheet_project_logistics_concept = CharField(
    max_length=255,
    default=None
)
These concepts appear as line items in the SheetProject when the maintenance is billed.

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Technical Documentation

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Maintenance Description

maintenance_description = TextField()
Detailed description of maintenance activities performed.
fault_description = TextField()
Description of the problem or failure (for corrective maintenance).
possible_causes = TextField()
Technical analysis of what caused the failure.
replaced_parts = TextField()
List of parts and accessories replaced during maintenance.
observations = TextField()
Additional notes and recommendations for future maintenance.

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Approval and Signatures

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Responsible Parties

# Technical staff who performed the work
performed_by = CharField(max_length=255)
performed_by_position = CharField(max_length=255)

# Supervisor who approved the work
approved_by = CharField(max_length=255)
approved_by_position = CharField(max_length=255)
While the system tracks the assigned responsible_technical, the performed_by and approved_by fields record the actual names for the maintenance report document.

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Maintenance Lifecycle

1

DRAFT

Maintenance sheet is being prepared:
  • Record equipment and location
  • Assign responsible technical
  • Document maintenance activities
  • Record parts used and costs
2

CLOSED (EN PLANILLA)

Work is complete and ready for billing:
  • All documentation finalized
  • Signatures obtained
  • Costs calculated
  • Added to work order (SheetProject)
3

VOID (ANULADO)

Maintenance was cancelled or voided:
  • Not included in billing
  • Archived for records

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Document Attachment

Attach the completed maintenance report PDF: 
maintenance_file = FileField(
    upload_to='projects/maintenance_sheets/',
    validators=[validate_pdf_file]
)

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Code Examples

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Creating a Preventive Maintenance Sheet

from projects.models import SheetMaintenance, SheetProject
from equipment.models import ResourceItem
from accounts.models import Technical
from datetime import date

# Create preventive maintenance
maintenance = SheetMaintenance.objects.create(
    id_sheet_project=sheet_project,
    # sheet_number is auto-generated
    maintenance_type='PREVENTIVO',
    resource_item=resource,
    responsible_technical=technical,
    requested_by='Supervisor de Campo',
    rig='RIG-45',
    code='BT-001',
    location='Campamento Norte',
    start_date=date(2026, 3, 15),
    end_date=date(2026, 3, 15),
    total_days=1,
    cost_day=150.00,
    cost_total=150.00,
    maintenance_description='''Mantenimiento preventivo:
        - Limpieza de tanques
        - Revisión de bombas
        - Lubricación de componentes
        - Inspección de mangueras y conexiones''',
    replaced_parts='Ninguno',
    observations='Equipo en buen estado. Próxima revisión en 7 días.',
    performed_by='Juan Técnico',
    performed_by_position='Técnico de Mantenimiento',
    approved_by='Carlos Supervisor',
    approved_by_position='Jefe de Operaciones'
)

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Creating a Corrective Maintenance Sheet

# Create corrective maintenance
maintenance = SheetMaintenance.objects.create(
    id_sheet_project=sheet_project,
    maintenance_type='CORRECTIVO',
    resource_item=resource,
    responsible_technical=technical,
    requested_by='Cliente - Emergencia',
    rig='RIG-23',
    code='PTRTAR-005',
    location='Campamento Sur',
    start_date=date(2026, 3, 18),
    end_date=date(2026, 3, 19),
    total_days=2,
    cost_day=200.00,
    cost_total=400.00,
    cost_logistics=100.00,
    fault_description='Motor del blower no arranca. Sin funcionamiento de aireación.',
    possible_causes='''- Falla eléctrica en relay del motor
        - Daño en el motor eléctrico
        - Problema en panel de control''',
    maintenance_description='''Reparación realizada:
        - Diagnóstico eléctrico completo
        - Reemplazo de relay del motor
        - Pruebas de funcionamiento
        - Ajustes finales''',
    replaced_parts='''- Relay del motor (marca Schneider, ref. LRD10)
        - Fusibles 10A (cantidad: 3)''',
    observations='Motor funcionando correctamente. Se recomienda revisión del panel de control en 30 días.',
    performed_by='Pedro Electricista',
    performed_by_position='Técnico Eléctrico',
    approved_by='María Ingeniera',
    approved_by_position='Ingeniera de Mantenimiento'
)

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Closing Maintenance for Billing

# Finalize maintenance
maintenance.status = 'CLOSED'
maintenance.save()

# It will now appear in the SheetProject for billing
# The cost_total + cost_logistics will be added as line items

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Querying Maintenance History

# Get all maintenance for an equipment item
history = SheetMaintenance.objects.filter(
    resource_item=resource,
    status='CLOSED',
    is_active=True
).order_by('-start_date')

# Get pending maintenance
pending = SheetMaintenance.objects.filter(
    status='DRAFT',
    id_sheet_project__project=project
)

# Get maintenance by type
preventive = SheetMaintenance.objects.filter(
    maintenance_type='PREVENTIVO',
    start_date__gte=date(2026, 1, 1)
)

corrective = SheetMaintenance.objects.filter(
    maintenance_type='CORRECTIVO',
    start_date__gte=date(2026, 1, 1)
)

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Scheduling Integration

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How Frequency Works

Maintenance frequency is defined at the ProjectResourceItem level: 
from projects.models import ProjectResourceItem

# Get resources due for maintenance
resources = ProjectResourceItem.objects.filter(
    project=project,
    is_retired=False,
    operation_start_date__lte=today,
    operation_end_date__gte=today
)

# Check each resource's frequency
for resource in resources:
    if resource.frequency_type == 'DAY':
        # Check if interval_days has passed since last maintenance
        pass
    elif resource.frequency_type == 'WEEK':
        # Check if today is in weekdays list
        if today.weekday() in resource.weekdays:
            # Schedule maintenance
            pass
    elif resource.frequency_type == 'MONTH':
        # Check if today's day is in monthdays list
        if today.day in resource.monthdays:
            # Schedule maintenance
            pass

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Best Practices

  • Schedule based on ProjectResourceItem frequency settings
  • Create maintenance sheets 1 day in advance
  • Complete work on scheduled date when possible
  • Document all activities even if minimal work performed
  • Create DRAFT immediately when failure reported
  • Assign qualified technical staff
  • Document fault description thoroughly
  • Take photos of damage (link in observations)
  • List all parts replaced with part numbers
  • Use consistent daily rates across projects
  • Include logistics costs when transportation required
  • Track parts costs separately in replaced_parts field
  • Verify total_days calculation matches date range
  • Write detailed maintenance descriptions
  • Include observations for future maintenance planning
  • Attach photos as PDF appendix if significant repairs
  • Get both performed_by and approved_by signatures

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Reporting and Analytics

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Maintenance Metrics

from django.db.models import Count, Sum, Avg
from datetime import timedelta

# Count maintenance by type
stats = SheetMaintenance.objects.filter(
    id_sheet_project__project=project,
    status='CLOSED'
).values('maintenance_type').annotate(
    count=Count('id'),
    total_cost=Sum('cost_total')
)

# Average maintenance duration
avg_duration = SheetMaintenance.objects.filter(
    status='CLOSED'
).aggregate(Avg('total_days'))

# Most maintained equipment
top_equipment = SheetMaintenance.objects.filter(
    status='CLOSED'
).values('resource_item__name').annotate(
    maintenance_count=Count('id')
).order_by('-maintenance_count')[:10]

Projects

ProjectResourceItem defines maintenance frequency

Equipment

Track maintenance history by equipment

Work Orders

Maintenance costs included in work orders

Reports

Generate maintenance sheet PDFs