Files
cheesy-arena-lite/field/plc.go
2018-09-01 22:13:27 -07:00

360 lines
8.7 KiB
Go

// Copyright 2017 Team 254. All Rights Reserved.
// Author: pat@patfairbank.com (Patrick Fairbank)
//
// Methods for interfacing with the field PLC.
package field
import (
"fmt"
"github.com/Team254/cheesy-arena/websocket"
"github.com/goburrow/modbus"
"log"
"time"
)
type Plc struct {
IsHealthy bool
IoChangeNotifier *websocket.Notifier
address string
handler *modbus.TCPClientHandler
client modbus.Client
inputs [inputCount]bool
registers [registerCount]uint16
coils [coilCount]bool
oldInputs [inputCount]bool
oldRegisters [registerCount]uint16
oldCoils [coilCount]bool
cycleCounter int
}
const (
modbusPort = 502
plcLoopPeriodMs = 100
plcRetryIntevalSec = 3
cycleCounterMax = 100
)
// Discrete inputs
type input int
const (
fieldEstop input = iota
redEstop1
redEstop2
redEstop3
blueEstop1
blueEstop2
blueEstop3
redConnected1
redConnected2
redConnected3
blueConnected1
blueConnected2
blueConnected3
scaleNear
scaleFar
redSwitchNear
redSwitchFar
blueSwitchNear
blueSwitchFar
redForceActivate
redLevitateActivate
redBoostActivate
blueForceActivate
blueLevitateActivate
blueBoostActivate
inputCount
)
// 16-bit registers
type register int
const (
red1Bandwidth register = iota
red2Bandwidth
red3Bandwidth
blue1Bandwidth
blue2Bandwidth
blue3Bandwidth
redForceDistance
redLevitateDistance
redBoostDistance
blueForceDistance
blueLevitateDistance
blueBoostDistance
registerCount
)
// Coils
type coil int
const (
heartbeat coil = iota
matchReset
stackLightGreen
stackLightOrange
stackLightRed
stackLightBlue
stackLightBuzzer
red1EthernetDisable
red2EthernetDisable
red3EthernetDisable
blue1EthernetDisable
blue2EthernetDisable
blue3EthernetDisable
coilCount
)
func (plc *Plc) SetAddress(address string) {
plc.address = address
plc.resetConnection()
}
// Loops indefinitely to read inputs from and write outputs to PLC.
func (plc *Plc) Run() {
// Register a notifier that listeners can subscribe to to get websocket updates about I/O value changes.
plc.IoChangeNotifier = websocket.NewNotifier("plcIoChange", plc.generateIoChangeMessage)
for {
if plc.handler == nil {
if plc.address == "" {
time.Sleep(time.Second * plcRetryIntevalSec)
plc.IsHealthy = false
continue
}
err := plc.connect()
if err != nil {
log.Printf("PLC error: %v", err)
time.Sleep(time.Second * plcRetryIntevalSec)
plc.IsHealthy = false
continue
}
}
startTime := time.Now()
isHealthy := true
isHealthy = isHealthy && plc.writeCoils()
isHealthy = isHealthy && plc.readInputs()
isHealthy = isHealthy && plc.readCounters()
if !isHealthy {
plc.resetConnection()
}
plc.IsHealthy = isHealthy
plc.cycleCounter++
if plc.cycleCounter == cycleCounterMax {
plc.cycleCounter = 0
}
// Detect any changes in input or output and notify listeners if so.
if plc.inputs != plc.oldInputs || plc.registers != plc.oldRegisters || plc.coils != plc.oldCoils {
plc.IoChangeNotifier.Notify()
plc.oldInputs = plc.inputs
plc.oldRegisters = plc.registers
plc.oldCoils = plc.coils
}
time.Sleep(time.Until(startTime.Add(time.Millisecond * plcLoopPeriodMs)))
}
}
// Returns the state of the field emergency stop button (true if e-stop is active).
func (plc *Plc) GetFieldEstop() bool {
return plc.address != "" && !plc.inputs[fieldEstop]
}
// Returns the state of the red and blue driver station emergency stop buttons (true if e-stop is active).
func (plc *Plc) GetTeamEstops() ([3]bool, [3]bool) {
var redEstops, blueEstops [3]bool
if plc.address != "" {
redEstops[0] = !plc.inputs[redEstop1]
redEstops[1] = !plc.inputs[redEstop2]
redEstops[2] = !plc.inputs[redEstop3]
blueEstops[0] = !plc.inputs[blueEstop1]
blueEstops[1] = !plc.inputs[blueEstop2]
blueEstops[2] = !plc.inputs[blueEstop3]
}
return redEstops, blueEstops
}
// Returns the state of the scale and the red and blue switches.
func (plc *Plc) GetScaleAndSwitches() ([2]bool, [2]bool, [2]bool) {
var scale, redSwitch, blueSwitch [2]bool
scale[0] = plc.inputs[scaleNear]
scale[1] = plc.inputs[scaleFar]
redSwitch[0] = plc.inputs[redSwitchNear]
redSwitch[1] = plc.inputs[redSwitchFar]
blueSwitch[0] = plc.inputs[blueSwitchNear]
blueSwitch[1] = plc.inputs[blueSwitchFar]
return scale, redSwitch, blueSwitch
}
// Returns the state of the red and blue vault power cube sensors.
func (plc *Plc) GetVaults() (uint16, uint16, uint16, uint16, uint16, uint16) {
return plc.registers[redForceDistance], plc.registers[redLevitateDistance], plc.registers[redBoostDistance],
plc.registers[blueForceDistance], plc.registers[blueLevitateDistance], plc.registers[blueBoostDistance]
}
// Returns the state of the red and blue power up buttons on the vaults.
func (plc *Plc) GetPowerUpButtons() (bool, bool, bool, bool, bool, bool) {
return plc.inputs[redForceActivate], plc.inputs[redLevitateActivate], plc.inputs[redBoostActivate],
plc.inputs[blueForceActivate], plc.inputs[blueLevitateActivate], plc.inputs[blueBoostActivate]
}
// Set the on/off state of the stack lights on the scoring table.
func (plc *Plc) SetStackLights(red, blue, green bool) {
plc.coils[stackLightRed] = red
plc.coils[stackLightBlue] = blue
plc.coils[stackLightGreen] = green
}
// Set the on/off state of the stack lights on the scoring table.
func (plc *Plc) SetStackBuzzer(state bool) {
plc.coils[stackLightBuzzer] = state
}
func (plc *Plc) GetCycleState(max, index, duration int) bool {
return plc.cycleCounter/duration%max == index
}
func (plc *Plc) GetInputNames() []string {
inputNames := make([]string, inputCount)
for i := range plc.inputs {
inputNames[i] = input(i).String()
}
return inputNames
}
func (plc *Plc) GetRegisterNames() []string {
registerNames := make([]string, registerCount)
for i := range plc.registers {
registerNames[i] = register(i).String()
}
return registerNames
}
func (plc *Plc) GetCoilNames() []string {
coilNames := make([]string, coilCount)
for i := range plc.coils {
coilNames[i] = coil(i).String()
}
return coilNames
}
func (plc *Plc) connect() error {
address := fmt.Sprintf("%s:%d", plc.address, modbusPort)
handler := modbus.NewTCPClientHandler(address)
handler.Timeout = 1 * time.Second
handler.SlaveId = 0xFF
err := handler.Connect()
if err != nil {
return err
}
log.Printf("Connected to PLC at %s", address)
plc.handler = handler
plc.client = modbus.NewClient(plc.handler)
plc.writeCoils() // Force initial write of the coils upon connection since they may not be triggered by a change.
return nil
}
func (plc *Plc) resetConnection() {
if plc.handler != nil {
plc.handler.Close()
plc.handler = nil
}
}
func (plc *Plc) readInputs() bool {
if len(plc.inputs) == 0 {
return true
}
inputs, err := plc.client.ReadDiscreteInputs(0, uint16(len(plc.inputs)))
if err != nil {
log.Printf("PLC error reading inputs: %v", err)
return false
}
if len(inputs)*8 < len(plc.inputs) {
log.Printf("Insufficient length of PLC inputs: got %d bytes, expected %d bits.", len(inputs), len(plc.inputs))
return false
}
copy(plc.inputs[:], byteToBool(inputs, len(plc.inputs)))
return true
}
func (plc *Plc) readCounters() bool {
if len(plc.registers) == 0 {
return true
}
registers, err := plc.client.ReadHoldingRegisters(0, uint16(len(plc.registers)))
if err != nil {
log.Printf("PLC error reading registers: %v", err)
return false
}
if len(registers)/2 < len(plc.registers) {
log.Printf("Insufficient length of PLC counters: got %d bytes, expected %d words.", len(registers),
len(plc.registers))
return false
}
copy(plc.registers[:], byteToUint(registers, len(plc.registers)))
return true
}
func (plc *Plc) writeCoils() bool {
// Send a heartbeat to the PLC so that it can disable outputs if the connection is lost.
plc.coils[heartbeat] = true
coils := boolToByte(plc.coils[:])
_, err := plc.client.WriteMultipleCoils(0, uint16(len(plc.coils)), coils)
if err != nil {
log.Printf("PLC error writing coils: %v", err)
return false
}
return true
}
func (plc *Plc) generateIoChangeMessage() interface{} {
return &struct {
Inputs []bool
Registers []uint16
Coils []bool
}{plc.inputs[:], plc.registers[:], plc.coils[:]}
}
func byteToBool(bytes []byte, size int) []bool {
bools := make([]bool, size)
for i := 0; i < size; i++ {
byteIndex := i / 8
bitIndex := uint(i % 8)
bitMask := byte(1 << bitIndex)
bools[i] = bytes[byteIndex]&bitMask != 0
}
return bools
}
func byteToUint(bytes []byte, size int) []uint16 {
uints := make([]uint16, size)
for i := 0; i < size; i++ {
uints[i] = uint16(bytes[2*i])<<8 + uint16(bytes[2*i+1])
}
return uints
}
func boolToByte(bools []bool) []byte {
bytes := make([]byte, (len(bools)+7)/8)
for i, bit := range bools {
if bit {
bytes[i/8] |= 1 << uint(i%8)
}
}
return bytes
}