Lenze DDS Target 9300 Servo PLC V8.x - Manual (Page 48)

2.8 DFIN_IO_DigitalFrequency (node number 21)
9300 Servo PLC
System blocks
2−42
L
9300 Servo PLC EN 5.1
Functional sequence
1. The TP is activated via a signal change at the digital input X5/E5 or via a zero pulse (only if an
encoder is connected).
2. If a TP has occurred, DFIN_bTPReceived_b is set = TRUE.
3. After the start of the task, DFIN_dnIncLastScan_p indicates the number of increments [inc]
counted since the TP.
4. Then DFIN_bTPReceived_b is set = FALSE.
Note!
·
It is necessary that all three outputs (DFIN_nIn_v, DFIN_bTPReceived_b and
DFIN_dnIncLastScan_p) are processed in the task even if just one signal is required.
·
The polarity of the digital input X5/E5 configured under C0114/5 does not affect the edge
evaluation.
DFIN_nIn_v
·
The value DFIN_nIn_v is scaled in increments per millisecond.
(INT) 16384 corresponds to 15000 rpm. See chapter 1.2.7, "Signal types and scalings".
( ^ 1−8)
·
For every task in which DFIN_nIn_v is used the operating system creates an individual
integrator that is reset after every start of the task (task−internal process image).
·
For a safe TP generation, DFIN_nIn_v must not be used in the PLC_PRG.
Example (DFIN_nIn_v in a 10 ms task):
·
When the 10 ms task starts, the value of the integrator is stored in a local area of the task and
the integrator is reset. The value in the local area gives an average value in increments per 1
ms.
·
If a position value is to be derived from this value, then it must be multiplied by
SYSTEM_nTaskInterval / 4 to get the result in increments per 10 ms, as in the example.
Example: In a 1−ms task, SYSTEM_nTaskInterval has the value 4 (4 x 250 ms = 1 ms).
·
In the Lenze FBs this process is already implemented.
2.8.1.3 Encoder cable monitoring ("FaultEncCable")
PIN 8 (LC) of the digital frequency input X9 monitors the cable / the upstream drive controller:
·
When PIN 8 is LOW, the "FaultEncCable" ("SD3") monitoring is triggered and the system
variable DFIN_bEncFaultCable_b is set to TRUE.
·
If the monitoring is not required, this input can be connected to +5 V.