Control Techniques COMMANDER SE, Руководство для продвинутых пользователей

Страница: 162 / 195

162
Commander SE Advanced User Guide
Issue Number: 4
12.4 Analog input 2
Analog input 2 is the remote current input, which is fed into terminal 5 on the control terminals. This input has 6 modes, which
can be selected.
If the 4 – 20 or 20 – 4mA modes are selected, the drive will trip on cL if the input reference is less than 3mA. If the drive trips
on cL, analog reference 1 cannot be selected.
If the 4 - .20 or 20 - .4mA modes are selected, the drive will not trip on cL if the input reference is less than 3mA. This will
allow analog reference 1 to be selected if analog reference 2 fails. A bit parameter, parameter
7.28 Current loop loss indicator
is provided so that this can be programmed to a digital output to give a signal if the analog 2 reference falls below 3mA.
Parameter set-up
Parameter 8.21 = parameter 7.28
Perform a Save routine: xx.00 = 1000 and press red Stop / Reset button on the drive
Connections
Control signal terminal block.
Operation
When the current into terminal 5 falls below 3mA, terminal 8 will go to +24V and therefore light the LED.
The signal from terminal 8 could go to a PLC or other type of signal monitoring system. The PLC or signal monitoring system
could then automatically switch terminal 12, Local/Remote speed reference select, to select analog reference 1 on terminal 2
so that the application can keep running with the minimum of downtime.
Alternatively
If it is required that the drive trips on cL and the reference must be changed back to analog reference 1 to allow the
application to continue running, the variable selector can be used to achieve this.
Set-up from default
1.21 = 0.2 Preset speed 1 to 0.2
1.22 = 0.4 Preset speed 2 to 0.4
8.39 = 1 Disable automatic set-up of terminals 12 and 13
8.26 = 12.10 Terminal 13 to control variable selector select bit
12.08 = 1.21 Variable select source 1 from preset speed 1
12.09 = 1.22 Variable select source 2 from preset speed 2
12.11 = 7.11 Variable select output to analog input 2 mode selector
Perform a Save routine: xx.00 = 1000 and press red Stop / Reset button on the drive
Operation
From default operation:
The drive will be running from a 4-20mA signal into terminal 5 with terminal 12 (Local/Remote) closed. If the 4-20mA signal
falls below 3mA, the drive will trip on cL. Terminal 13 can then be closed so that variable selector out will select 4-20mA
without cL trip on parameter
7.11 (4-.20). Then terminal 12 can be opened and the drive reset so that it can run from a 0 to
10V input on terminal 2.
Mode Description
0 – 20 Current input 0 to 20mA (20mA full scale)
20 – 0 Current input 20 to 0mA (0mA full scale)
4 – 20 Current input 4 to 20mA with current loop loss (cL) trip (20mA full scale)
20 – 4 Current input 20 to 4mA with current loop loss (cL) trip (4mA full scale)
4 - .20 Current input 4 to 20mA with no current loop loss (cL) trip (20mA full scale)
20 - .4 Current input 20 to 4mA with no current loop loss (cL) trip (4mA full scale)