5
ANTRIEBSTECHNIK
6
2
5
KEB COMBIVERT F4-C
Name: Basis
6
16.02.00
Section
Page
Date
©
KEB Antriebstechnik, 1999
All Rights reserved
Chapter
Functional Description
Analog In- and Outputs
6.2.4
Buffer Memory
(An.22)
In order to control various inverters with different frequencies via the analog output of
a PLC, an analog memory was implemented. It is adjustable with parameter An.22
and controlled with a programmable digital input.
For a better understanding, a short example follows:
Five inverters (each operating one conveyor) shall be controlled by a PLC with ana-
log setpoint values. Due to different values, a parallel control is out of question; for
cost reasons, the same is true for a PLC with five analog outputs.
Generally there are enough digital outputs at the PLC and we use them for releasing
the analog input of the inverter. (like a CS-signal in the digital technic) The analog
inputs will parallely be switched to an analog output at the PLC. If the CS-signal is
set, the inverter operates with the actual value. If the CS-signal is switched off, the
inverter operates with the analog value, which was applied up to this point of time. In
this way, e.g. all inverters together can be started up. If the first inverter has reached
his setpoint value, the CS-signal is switched off for this inverter. If the next inverter
has reached his setpoint value, the CS-signal also will be switched off (and so on).
Depending on the specific kind of operation, it is also possible to set each inverter to
the setpoint value seperately.
S2
S1
Permanent
Buffer
An.22=1/2/16
Direct Mode
Buffer Mode
progr. digital input di.3...di.10 Value 11/12/13
Analog value from input (set)
Analog value from buffer (not set)
An.22=4/8/32
Buffer clean at
Power off
Picture 6.2.4
Principle of buffer memory
from input
filter
to the
characteristics
amplifier
Coming from the input filter, the memory mode can be switched on with An. 22. If the
programmable digital input will be set now (S1 closed;S2 open) the analog signal will
directly be transmitted and parallely stored in the non-volatile memory. As soon as
the digital input will be switched off (S1 open; S2 closed), the inverter will continue to
operate with the value stored in the memory. In addition it can be determined with
An.22 whether the storage contents shall be conserved or cancelled
.
An.22
Function
0 = off
1 = on
Memory mode for ±REF
0 = off
2 = on
Memory mode for REF
0 = off
4 = on
Delete ±REF-memory when switching off
0 = off
8 = on
Delete REF-memory when switching off
0 = off
16 = on
memory mode for analog option
0 = off
32 = on
Delete memory for analog option when switching off
0 = off
64 = on
Simulation of analog Option by ±REF (s. picture 6.2.1)
0 = off
128 = on
Displays after input amplifier (s. picture 6.2.1)
An.22 Analog-In-Mode
The sum of all „on“ values has to
be entered in An.22
