DZ27001a_e.doc / Jan-13
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8.4. Monitoring of remote motion enable signals
The unit provides a special "Command Monitor" function for logical control of a motion enable
signal and the resulting response of the system. In addition to the normal monitoring functions
this mode is suitable to generate alarm outputs under any of the following conditions:
motion is disabled, but still the system moves
motion is enabled, but the system does not move at all (mechanical deadlock), or the
system does not reach the scheduled speed within an expected time (overload)
the motion command changes over from "enable" to "disable" but the system does not
come down to standstill within an expected time
The following parameter settings will activate the Command Monitor function:
8.4.1.
Definition of a speed window
The application requires one of the relays to operate in overspeed mode (Preselect Mode = 0)
and another relay to operate in underspeed mode (Preselect Mode = 1). This will define a
window for the expected speed under regular motion conditions (see 6.2.9)
8.4.2.
Assignment of a control input
One of the two control inputs has to be set to the control function "12" to activate the
monitoring of the command. This input must be connected to the remote Enable/Disable signal
(see parameters "Input Function" under 6.2.6)
8.4.3.
Assignment of the control polarity
Parameter "Input Config" provides setting of the input polarity as follows:
Input Config = 0
=>
Motion disabled (stop) corresponds to input level "LOW"
Motion enabled (run) corresponds to input level "HIGH"
Input Config = 1
=>
Motion disabled (stop) corresponds to input level "HIGH"
Motion enabled (run) corresponds to input level "LOW"
8.4.4.
Setting of a Start-up delay time
Any signal changes from "disable" to "enable" or vice-versa will require some delay until the
system could really follow the command (acceleration or deceleration). Therefore it is
mandatory to set an appropriate start-up delay time (to the relay/output responsible for
"underspeed" only). See "Start Up Mode" and "Start Up Relay" under 6.2.9
8.4.5.
Setting of an appropriate Standstill definition
Under parameter "Standstill Time" an appropriate time must be set.
It is important to set a time higher than the Start-up delay time!
The command monitor uses always the same relay/transistor output to which the
underspeed function has been assigned
While the command monitor function is active, you can see an indicator box in the
PI/PO column of the PC screen. The "Command Monitor" box shines blue when the
motion command is in "Disable" state
