Siemens SINUMERIK 840D Description Of Functions page 148

4 Firmware Drive Functions
4.12 Terminals
Velocity controller
enable
4-148
SINUMERIK 840D/SIMODRIVE 611 digital Descr. of Functions HLA Module (FBHLA) – 04.00 Edition
Operating sequence for PD (power disable):
S
24 V supply for shutoff valve is disconnected immediately (shutoff valve
closes).
S
If MD 5530 bit 4=0 is set, the 24 V supply for the servo solenoid valve is also
switched off when the manipulated variable enable delay (MD 5531) runs
down (servo solenoid valve moves to fail-safe position).
If MD 5530 bit 4=1 is set, the 24 V supply for the servo solenoid valve re-
mains connected.
S
If MD 5530 bit 0=0 is set (no shutoff valve), then the 24 V supply for the
servo solenoid valve is switched off immediately (servo solenoid valve
moves to fail-safe position).
S
"Velocity controller enable" status bit is reset immediately.
– Valve setpoint=0 V is output
– I-action components of controllers are cancelled.
– Valve spool monitoring is deactivated
S
If a central shutoff valve is installed, it is the user's responsibility to gate
the signals (e.g. using the PLC) in such a way that the central shutoff valve
is actuated when the power is disabled.
To prevent errors on other axes, it should be ensured that all axes whose
pressure is supplied via the central shutoff valve also receive the "power
disable" command when the central shutoff valve is actuated.
S
If a separate shutoff valve (axis-specific shutoff valve) is installed for each
axis, this need only be connected to the "shutoff valve" relay output of the
relevant axis.
After the power has been disabled, the switch for the 24 V supply is either
opened or not (depending on the setting of bit 4 in MD 5530) at the end of the
manipulated variable enable delay. The default setting has been selected such
that the 24 V valve supply voltage is disconnected (bit 4 =0) so as to bring the
valve into the fail-safe position.
This will not be necessary if a shutoff valve is installed and actuated. This func-
tion has been integrated for cases where a shutoff valve is parameterized, but
not actually connected. In such cases, this function prevents the drive from be-
ing able to drift after a power disable. After a function test, bit 4 in MD 5530 can
be set to 1.
A velocity controller enable/disable can be requested via the following paths:
S
Terminal 64 (central velocity controller enable)
S
Control word (from NC)
S
Error (ZK1)
If a velocity controller enable is requested and all the relevant enable conditions
are fulfilled, i.e.
S
manipulated variable enable delay run down,
S
24 V supply for shutoff and SS valves ON,
S
power enable signal set and
S
no errors,
then the "Velocity controller enable" status bit is set.
 Siemens AG 2000. All rights reserved
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