Curtis 1232E Manual page 153

Fig. B-1
Supervisory
system in Curtis enhanced
AC motor controllers.
Curtis 1232E/34E/36E/38E & 1232SE/34SE/36SE Manual,
2 4 N O V E M B E R 2 0 1 5
EN13849 COMPLIANCE
Since January 1, 2012, conformance to the European Machinery Directive
has required that the Safety Related Parts of the Control System (SRPCS)
be designed and verified upon the general principles outlined in EN13849.
EN13849 supersedes the EN954 standard and expands upon it by requiring
the determination of the safety Performance Level (PL) as a function of Desig-
nated Architecture plus Mean Time To Dangerous Failure (MTTFd), Common
Cause Faults (CCF), and Diagnostic Coverage (DC). These figures are used by
the OEM to calculate the overall PL for each of the safety functions of their
vehicle or machine.
The OEM must determine the hazards that are applicable to their vehicle
design, operation, and environment. Standards such as EN13849-1 provide
guidelines that must be followed in order to achieve compliance. Some indus-
tries have developed further standards (called type-C standards) that refer to
EN13849 and specifically outline the path to regulatory compliance. EN1175-1
is a type-C standard for battery-powered industrial trucks. Following a type-C
standard provides a presumption of conformity to the Machinery Directive.
Curtis Enhanced AC Motor Controllers comply with these directives
using advanced active supervisory techniques. The basic "watchdog" test circuits
have been replaced with a Supervisor microcontroller that continuously tests
the safety related parts of the control system; see the simplified block diagram
in Figure B-1.
PRIMARY MOTOR CONTROL
Inputs
MICROPROCESSOR
Communication
MICROPROCESSOR
The Supervisor and Primary motor control processors run diagnostic
checks at startup and continuously during operation. At startup, the integrity
of the code and EEPROM are ensured through CRC checksum calculations.
RAM is pattern checked for proper read, write, and addressing. During opera-
tion, the arithmetic and logic processing unit of each micro is cyclically tested
through dynamic stimulus and response. The operating system timing and
task sequencing are continuously verified. Redundant input measurements are
crosschecked over 30 times per second, and operational status information is
passed between microprocessors to keep the system synchronized. Any faults
os
APPENDIX B: EN13849 COMPLIANCE
APPENDIX B
DRIVERS
Monitor
Monitor
Link
SUPERVISOR
Shutdown
30
Outputs
AC
POWERBASE
MOTOR
B-1