Siemens Sinumerik 840D Series Function Manual page 148

4 Firmware Drive Functions
4.12 Terminals
4-148
Figs. 4-19 and 4-20 show the system response to 24 V ON and OFF for a con-
figuration with and without shut-off valve.
Chronological sequence after connection of 24 V with shutoff valve
Power enable and velocity controller commands issued, setpoint > 0
24 V supply
24 V missing
message
Switch for servo
closed
solenoid valve
open
supply
Valve spool
zero
position
Fail-safe
Switches
closed
Shutoff valve
open
Shutoff valve
open
closed
Status bit
power enable
Status bit
Velocity
controller enable
Effective
velocity
setpoint
Fig. 4-19 Chronological sequence after connection of 24 V supply, with shut-off valve
Chronological sequence after connection of 24 V supply without shutoff valve
Power enable and velocity controller enable commands issued, setpoint > 0
24 V supply
24 V missing
message
Switch for servo
closed
solenoid valve
open
supply
Valve spool
zero
position
Fail-safe
Switches
closed
Shutoff valve
open
Shutoff valve
open
closed
Status bit
power enable
Status bit
Velocity
controller enable
Effective
velocity
setpoint
Fig. 4-20 Chronological sequence after connection of 24 V supply, without shut-off valve
SINUMERIK 840D/SIMODRIVE 611 digital, HLA Module (FBHLA) - 10.03 Edition
The valve supply is disconnected
only if bit 4 in MD 5530 is set to
Backup capacitor maintains
24 V for valve electronics
Power enable delay
Output value enable
delay
Power enable delay MD 5532
No shutoff valve connected
Output value delay MD 5531
 Siemens AG, 2003. All rights reserved
02.99
10.03