Siemens SINUMERIK 840D Description Of Functions page 146

4 Firmware Drive Functions
4.12 Terminals
4-146
SINUMERIK 840D/SIMODRIVE 611 digital Descr. of Functions HLA Module (FBHLA) – 04.00 Edition
Figs. 4-17 and 4-18 show the system response to 24 V ON and OFF for a con-
figuration with and without shutoff 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
closed
servo solenoid
open
valve supply
Valve spool
Zero
position
Fail-safe
Switch for
closed
Shutoff valve
open
Shutoff valve open
closed
Status bit
Power enable
Status bit
Velocity
controller enable
Effective
velocity
setpoint
Fig. 4-17 Chronological sequence after connection of 24 V supply, with shutoff valve
Chronological sequence after connection of 24 V 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
Switch for
closed
Shutoff valve
open
Shutoff valve
open
closed
Status bit
Power enable
Status bit
Velocity
controller enable
Effective
velocity
setpoint
Fig. 4-18 Chronological sequence after connection of 24 V supply, without shutoff valve
The valve supply is disconnected only
if bit 4 in MD 5530 is set to zero
Back-up capacitor prolongs 24 V
supply for valve electronics
Power enable delay time
Manipulated variable enable delay
Power enable delay period MD 5532
No shutoff valve connected
Manipulated variable delay time MD 5531
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