Petruzella F.D. Programmable Logic Controllers
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Index 393
and monitoring, 276–278
off-delay timers, 342–343
on-delay timers, 339–342
PLC programming languages, 79–81
processor memory organization, 72–76
program scan, 76–79
relay-type instructions, 81–84
retentive timer on, 344–345
word-level instructions, 67–68
Programming devices, 7, 37–38
Programming languages, 7, 8, 64, 79–81
Programming terminal devices, 37–38
Programs, 7
CLX controllers, 320–321
editing and commissioning, 275
noninterchangeable, 4
sequencer, 248–254
Projects (CLX controllers), 319–321
programs, 320–321
routines, 321
tasks, 320
Proportional (P) control, 219, 220, 297–299
Proportional plus derivative (PD) control, 299
Proportional-integral (PI) control, 219, 299
Proportional-integral-derivative (PID) control, 219–221, 299–301
Proportioning action, 297–299
Protection
enclosure for, 269–271
input, 33
short circuit, 32
Protocols, 305–306
Common Industrial Protocol, 309–311
communications, 287
Proximity sensors, 101–104
Pulse width modulation, 298
Pushbutton switches, 98
PV (process variable), 220, 295
R
Rack-based I/O sections, 18–19
Rack-based memory systems, 72
Rack/slot-based addressing, 19–20
Radiated noise, 271
Radix, 44
RAM (random-access memory), 36–37
Rate action, 299
Read-only memory (ROM), 36
Reading from memory, 35
REAL base tags, 324
Real world inputs/outputs, 6
Recommended standards (RSs), 308
RS-232 standard, 287
for serial communications, 308
Recording data, 38
Recoverable faults, 194
Redundant media, 311
Redundant processors, 34
References, 362
Registers (data memory), 201
Relay ladder logic (RLL), 7–9, 11
Relay ladder schematics, 64–67
Relay output, 26
Relay schematics
contactors, 97–98
converting into PLC ladder programs, 116–119
electromagnetic control relays, 96–97
latching relays, 111–115
Process control system, 292
con gurations, 292–294
structure of, 294–296
Process variable (PV), 220, 295
Processor module, troubleshooting, 279
Processors, 34–35, 72–76; see also CPU
Produced tags, 323
PROFIBUS-DP, 313
PROG (program mode), 34
Program control instructions, 176–195
fault routine, 194
forcing external I/O addresses, 187–190
immediate input, 184, 186
immediate output, 186–187
jump, 180–181
master control reset, 177–180
override instructions, 177
safety circuitry, 190–193
selectable timed interrupt, 193–194
subroutines, 181–185
suspend, 195
temporary end, 194–195
Program les, 72
Program mode (PROG), 34, 91
Program scan, 76, 329–330
Program scan cycle, 76–79
Program tags, 322
Programmable automation controllers (PACs), 12, 317; see also
Allen-Bradley ControlLogix (CLX) controllers
Programmable logic, 64–68
Programmable logic controllers (PLCs), 1–14; see also speci c
controllers
architecture, 4, 5
bene ts of, 2–4
communications capability with, 2–4
cost savings with, 2, 3
xed vs. modular input/output, 4–6
exibility with, 2
input/output system, 6, 7
instruction set, 14
matching applications and, 12–13
memory, 13
modifying operation of, 11
in motion control systems, 302
PCs vs., 11–12
power supply, 4–6
principles of operation, 8–11
processor, 5, 6
programmable automation controllers, 12
programming device, 7
programming languages, 7, 8
programs, 7
reliability of, 2
response time, 7, 8
size, 12, 13
troubleshooting, 3, 4
Programming, 71–91
branch instructions, 85–87
CLX counters, 347–351
CLX timers, 338–345
entering ladder diagrams, 89–91
Examine If Closed instruction, 88–89
Examine If Open instruction, 88–89
function block, 361–370
instruction addressing, 84
internal relay instructions, 87
modes of operation, 91
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394 Index
Sensors, 101–108
ow, 107
light, 104–106
magnetic reed switches, 104
position, 108
in process control systems, 294
proximity, 101–104
relay schematics, 101–108
strain/weight, 106–107
temperature, 107
ultrasonic, 106
velocity, 108
Sequencer compare (SQC), 245, 252–253
Sequencer input (SQI), 245, 251–252
Sequencer load (SQL), 245, 253–254
Sequencer output (SQO), 245–251
Sequencers, 243–254
instructions, 245–248
mechanical, 243–244
programs, 248–254
Sequential control process, 116
Sequential function chart (SFC) language, 79, 80
Serial data communications, 303, 308
Serial transmission, 307–308
Series connections, 59
Servo drive, 302
Servo motors, 110, 302–303
Set-point (SP), 220, 295
Set-point control, 218–219
Setup display screens, 295
Setup procedure (CLX controllers), 365
Seven-segment LED display board, 216–217
SFC (sequential function chart) language, 79, 80
Shift registers, 254–263
bit, 254–260
word shift operations, 260–263
Short circuit protection, 32
Shutdown periods, 278
Siemens S7-200 Micro PLC, 313
Sign bit, 46
Signal conditioning, 294
Single Integer base tag (SINT), 324
Single-ended applications, 13
Single-scan test mode, 91
Single-step test mode, 91
Sinking (NPN) circuits, 26
SINT (Single Integer base tag), 324
Size of PLCs, 12, 13
SLC 500 controllers; see Allen-Bradley SLC 500 controllers
Slot (rack/slot-based addressing), 19
Soft PLCs, 20, 22
SoftLogix 5800 controller, 317
Software, 12; see also Allen-Bradley RSLogix software
for PACs vs. PLCs, 317
PLC programming, 286–287
RSLinx, 286–287
Solar cells, 104
Solenoid valves, 109
Source register, 202
Sourcing (PNP) circuits, 26
SP (set-point), 220, 295
Special I/O modules, 29–31
SQC (sequencer compare), 245, 252–253
SQI (sequencer input), 245, 251–252
SQL (sequencer load), 245, 253–254
SQO (sequencer output), 245–251
SQR (square root) command, 227, 233
Relay schematics —Cont.
manually operated switches, 99–100
mechanically operated switches, 100–101
motor starters, 98–99
output control devices, 108–110
seal-in circuits, 110–111
sensors, 101–108
Relay-type instructions, 81–84
Reliability, 2
Remote mode (REM), 34, 91
Remote racks, 19
Repeatability, 311
Repeaters, 304
RES (retentive timer reset) command, 128, 137
Reserved le ( le 1), 72
Reserved le ( le 8), 73
Reset action, 299
Resolution
of analog input channels, 28
analog I/O modules, 33
stepper motors, 110
Response, of PID loop, 300
Response time, 7, 8, 32
RET (return), 182
RET (Return from Subroutine), 177
Retentive instructions, 178
Retentive timer on (RTO), 128
CLX controllers, 344–345
SLC 500 controllers, 128
Retentive timer reset (RES) command, 128, 137
Retentive timers, 128, 136–140
Retrieving data, 38
Retrore ective scans, 104–105
Return (RET), 182
Return from Subroutine (RET), 177
RLL (relay ladder logic), 7–9, 11
Robots, 302–303
ROM (read-only memory), 36
Routines, 321
RS-232 standard, 287
RSLinx software, 286–287, 318, 319
RSLogix software; see Allen-Bradley RSLogix software
RSs (recommended standards), 287, 308
RSWho, 318
RTO (retentive timer on), 128
CLX controllers, 344–345
SLC 500 controllers, 128
Run mode (RUN), 34, 91
RUN operation, 9–10
S
Safety circuitry, 190–193
Safety PLCs, 192
SBR (subroutine) command, 177, 182
SCADA; see Supervisory control and data acquisition
Scale data (SCL), 235
Scan cycle time, 77
Scans, 10
SCL (scale data), 235
Scope (of tags), 322, 325
Seal-in circuits, 110–111
Select Processor Type Window (RSLogix 500), 90
Selectable timed disable (STD), 194
Selectable timed enable (STE), 194
Selectable timed interrupt (STI), 193–194
Selector switches, 100
Semiautomatic controller tuning, 301
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Index 395
Thermocouples, 107
Thermostats, 100–101
Thumbwheel modules, 29
Thumbwheel switches (TWS), 216, 217
Time base, 128, 130
Time proportioning, 298
Time-delay circuit, 213
Time-driven sequencer programs, 248
Timer data le, 208
Timer le ( le 4), 72, 74
Timer number, 130
Timer Off-Delay (TOF) command, 14, 128
Timer On-Delay (TON) command, 14, 128
Timer Timing Bit (TT)
CLX controller timer, 338
SLC 500 timers, 130
Timers, 125–143
cascading, 140–143
CLX controllers, 338–345
combining counter functions and, 166–170
instructions, 128–129
mechanical timing relays, 126–128
off-delay, 126–128, 133–137, 342–343
on-delay, 126–134, 213–214, 339–342, 344–345
prede ned structure, 338–339
retentive, 128, 136–140
time-delay circuit, 213
watchdog, 279
TND (temporary end), 177, 194–195, 282, 283
TOD (convert to BCD), 227, 234
TOF (Timer Off-Delay) command, 14, 128
TOFs; see Off-delay timers
Token passing networks, 306
TON (Timer On-Delay) command, 14, 128
TONs; see On-delay timers
Transistor output, 26
Transistor-Transistor-Logic (TTL) modules, 30
Transitional contact circuit, 156
Transmission media, 303–304
Transmission methods, 307–308
Transmitting PLC data, 307–308
Trend values display screens, 295
Triac output, 26
Troubleshooting, 3, 4, 11, 279–286
input malfunctions, 279–280
ladder logic program, 281–286
locating addresses in ladder program, 277
output malfunctions, 281
processor module, 279
Truth tables, 58
TT (Timer Timing Bit)
CLX controller timer, 338
SLC 500 timers, 130
TTL (Transistor-Transistor-Logic) modules, 30
Turbine-type owmeters, 107
Two-position control, 220
TWS (thumbwheel switches), 216, 217
Type (rack/slot-based addressing), 19
U
UA (Update Accumulator) Bit, 154
Ultrasonic sensors, 106
UN (Under ow Bit)
CLX controllers, 348
SLC 500 counters, 154
Unipolar analog I/O modules, 28
Unlatch instructions (CLX controllers), 334–335
ST (structured text) language, 79–81
Star topology networks, 304
Start fence (MCR zone), 178
Static control, 35
Stations, 304
Status data le, 73
Status le ( le 2), 72
Status information, 18
STD (selectable timed disable), 194
STE (selectable timed enable), 194
Stepper motors, 109–110
Stepper-motor modules, 30
STI (selectable timed interrupt), 193–194
Stop buttons, 192–193
Storage bits, internal, 87
Store (STR)–Load (LD), 61
Store Not (STR NOT)–Load Not (LD NOT), 61
Strain gauge load cells, 107
Strain gauges, 106–107
Strain/weight sensors, 106–107
Structured text (ST) language, 79–81
Structures (CLX controller tags), 324–325
SUB (subtract) command, 227
CLX controllers, 354
SLC 500 controllers, 229–230
Subroutine (SBR) command, 177, 182
Subroutine ladder program les ( les 3-255), 72
Subroutines, 181–185, 321
Subtract (SUB) command, 227
CLX controllers, 354
SLC 500 controllers, 229–230
Subtraction, 227
binary, 52–54
math instructions, 229–230
Supervisory control and data acquisition (SCADA), 313–314
local area networks for, 304
networking PLCs for, 35
Surge suppressors, 274–275
Suspend (SUS), 177, 195, 282, 283
Suspend mode, 282, 283
Symbolic instructions, 81
Symbols
logic, 58
timers, 127
Synchronous operation, 261
System functions le ( le 0), 72
T
Tables (data memory), 201
Tachometer generators, 107
Tag description, 325
Tag name, 325
Tag name (CLX controller timer), 338
Tag type, 325
Tag-based addressing, 19–21, 331–332
Tag-based memory systems, 72
Tags (CLX controllers), 321–324
arrays, 326–327
creating, 325
monitoring and editing, 326
structures, 324–325
Tasks (CLX controllers), 320
Temperature, inside PLC enclosure, 269
Temperature sensors, 107
Temperature switches, 100–101
Temporary end (TND), 177, 194–195, 282, 283
Test mode, 91
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396 Index
Wireless Wi-Fi Ethernet networks, 303–304
Wires (function blocks), 362, 363
Wiring, 8–10, 271–272
Word addressing format, 20
Word shift operations, 260–263
Word-level instructions
math, 233–234
programming, 67–68
Words
binary system, 45
in data les, 73
data manipulation, 201
in rack/slot-based addressing, 19
Wrist (robot arm), 303
Writing
to memory, 35
over existing data, 201
X
XIC (Examine If Closed), 81–82, 88–89
XIC (Examine ON), 14
XIO (Examine If Open), 82, 88–89
XIO (Examine OFF), 14
XOR (exclusive-OR) command, 201
XOR (exclusive-OR) function, 61
Unlatching relays, 111–112
Up-counters, 150, 152–159; see also CTU (count-up) counters
CLX controllers, 348–350
one-shot instruction, 155–159
preset values, 151
program and timing diagram, 152–153
SLC 500 controllers, 153–154
using LES instruction, 215
Update Accumulator (UA) Bit, 154
User-de ned les ( les 10-255), 73
User-de ned structures (CLX controllers), 325
Utilization, memory, 35–36
V
Velocity sensors, 108
Vertical scan, 79
Volatile memory, 36
Voltage(s)
electrostatic, 35
input threshold, 32
input/output ranges, 33
nominal input, 32
output, 32
variations/surges in, 274–275
Voltage sensing analog I/O modules, 27, 28
Voltage sources, eld-supplied, 22, 23
W
Watchdog timers, 279
Wire connectors (function blocks), 363
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