Accelnet Plus Micro Modules User Guide
16-01687 Rev 03
Copley Controls
Page 99 of 139
C
ONTROL
M
ODES AND
STO
The drive can control the position, velocity, and torque of motors while operating from a
number of control sources. But it can only do this when the STO function is inactive. And,
although the digital control core and firmware of the drive can observe the state of the STO
function, it cannot interact with, or exercise any control over the STO function.
The STO function operates completely independently of the control core of the drive.
It does not depend on the control core for its operation and the control core of the
drive has no control over the STO function.
STO
I
NPUT
S
IGNAL
L
EVEL
The STO inputs (STO-IN1, STO-IN2) are +3.3V logic level inputs with +5V nominal and
+6V maximum ratings
In typical machinery, STO inputs are driven from a safety relay or similar device with 24Vdc
level signals. The AEV/APV models are not designed as stand-alone devices and are designed
for installation as components on the end user motherboard. It is the responsibility of the
designer of the larger system to take this into consideration that the motherboard design
must contain level translation and overvoltage protections to interface between 24V (nominal)
signals and the STO inputs on the AEV/APV drives. A constraint on the larger system is that
the power supply used to drive the STO inputs must be a SELV or PELV type.
STO
DC
P
OWER
S
UPPLY
The recommended DC power for STO inputs on the AEV and APV Modules should be +5 Vdc
nominal, +6 Vdc maximum, and must be supplied by power supplies with a
SELV or PELV rating.
The EZ board has STO inputs that are +24 Vdc compatible, +30 Vdc maximum,
in addition to the +5 Vdc inputs.
W
IRING TO THE
STO
I
NPUTS
Electrical connections to the STO inputs must meet the requirements for fault exclusions for
short circuits between conductors and short circuits between conductors and other conductive
parts or earth or the protective bonding conductor. Fault exclusion requirements are given in
ISO 13849-2 and IEC 61800-5-2.
Connections to the STO inputs must provide spacing that is greater than the minimum
creepage and clearance of 1.24 mm. that is required for fault exclusion when considering the
FMEDA (Failure Modes, Effects, and Diagnostic Analysis) of the system.