Safety PLCs
GuardPLC Safety Control Systems
Overview
Safety-related input modules are automatically subjected to a high-
grade, cyclical self-test in both the GuardPLC 1200 and GuardPLC
2000 systems during operation. These test routines are TÜV
approved and help ensure the safe function of the respective
module. When an error is detected, the application is provided with
an “0” signal, and a detailed error message is generated optionally. If
there are minor failures in the module (no effect on the safety
function), no user diagnostic information is generated.
• The GuardPLC 2000 digital I/O module has 24 inputs and 16
outputs for signals, and the inputs and outputs are electrically
isolated in groups of eight. The GuardPLC 1200 digital I/O
module has 20 inputs and 8 outputs. In case of module error, the
outputs are switched to the de-energized state.
• The analog output module, which is available in the GuardPLC
2000 system only, the eight channels on the analog input module
can be used as eight single-ended or four differential analog
inputs for 0 to 20 mA. No mixing is allowed. The incoming
signals are converted into an integer value with a 12-bit
resolution. This value then can be used in the user program. In
case of module error, the logic outputs of the modules are
switched to the de-energized state.
• The analog output module, which is available in the GuardPLC
2000 system only, has eight analog outputs with a 12-bit
resolution. They are electrically isolated in groups of two outputs
with a common ground. The output ranges of the module can be
switched to 0 to 21 mA, 0 to 10.25V DC or -10.25 to +10.25V
DC. For each channel, the module has a switch placed on the
printed circuit board to switch the different output ranges. In
case of module error, the outputs are switched to the de-
energized state.
• The counter module has two operating modes: counter mode and
decoder mode. The module has 24-bit counters with two outputs
each. The counters can operate in both directions (up and down)
and have a separate reset input. The input signals of 5V can be in
a frequency range of 0 to 1 MHz in a GuardPLC 2000 system.
Use a PC to configure the input voltage, which can be 5V or in a
range of 10 to 26.4V. In case of module error, the outputs are
switched to the de-energized state. The counter can count pulses
with direction and reset inputs up to 1 MHz in the GuardPLC
2000 system and up to 100 KHz in the GuardPLC 1200 system.
The counter module can also be used as an 8-bit gray code
encoder in the GuardPLC 2000 system or a 6-bit gray code
encoder in the GuardPLC 1200 system.
I/O Hardware
Safety Digital I/O Combination Module
Max
Maximum
Operating
Continuous Number
Catalogue
Operating Signal Delay Off-State On-State Number Voltage/ Signal Delay Current
of
Number
Voltage
(max)
Current
Current of Inputs
Type
(max)
per Output Outputs Applications
1755–
GuardPLC
GuardPLC
2000
2000
Safety
on = 70µs
on = 70
µs
applications
off = 70
µs
off = 15
µs
2mA @ 10V
2A (8A
1.5mA @
18.4-
requiring 24V
10-30V
13mA @
24
total per
16
5V DC
26.8V DC
DC inputs and
–IB24XOB16
DC
30V
module)
GuardPLC
GuardPLC
24V DC
1200
1200
outputs
on = 120
µs
on = 15
µs
off = 200
µs
off = 90
µs
Safety Analog I/O Modules
Number of Inputs/
Outputs
4 differential or 8
single–ended inputs
— selectable
8 outputs
Back Plane
Current Load
150 mA/3.3V DC
400 mA/24V DC
150 mA/3.3V DC
400 mA / 24V DC
Channel Update/
Resolution
12 bits (0-1000)
Catalogue
Number
1755–
IF8
Data Format
12-bit signed
Integer (natural
binary)
12-bit signed
Integer (natural
binary)
Voltage Range
±10V
0-10V DC
±10V
0-10V DC
Current Range
0-20.5mA
(with shunt)
0-20mA
12 bits (0-1000)
OF8
Safety Counter Module
Inputs
2
Maximum Input
Frequency
1 MHz
Outputs
4
Location
Any unused slot
Back Plane Current Load Catalogue Number
0.1A / 24V DC without load
0.8A (3.3V DC), 0.1A (5V
1755-HSC
DC)
8-9
ALLEN-BRADLEY [ Allen-Bradley ]
