ABB DCS 500B Guía Rápida De Instalación Y Configuración página 12

• Control
The relay logic can be split into three parts:
a: Generation of the ON/OFF and START/STOP command:
The commands represented by K20 and K21 (latching interface relay) can be generated by a PLC and transferred to the
terminals of the converter either by relays, giving galvanic isolation or directly by using 24V signals. There is no absolute
need to use hardwired signals. These commands can be transferred via a serial link system too. Even a mixed solution
can be realized by selecting the one or the other possibility for the one or the other signal.
b: Generation of control and monitoring signals:
The main power contactor K1 for the armature circuit is controlled by a dry contact located on the electronic power supply
board. The status of this contactor is checked by the converter via binary input 3. The field supply contactor K3 is controlled
by the auxiliary contact K11 connected to a binary output of the converter. The binary outputs consist of relay drivers,
capable to give appr. 50 mA each and a current limitation of around 160 mA for all of the outputs. The contactors K6 and
K8 control the fans of the drive system. They are controlled by the auxiliary contact K10 (similar to K11). In series with
K6 is an auxiliary contact of the circuit breaker F6, which monitors the motor fan supply. For the converter fan supply
monitoring the contact of the temperature detector is used in series with K8. Auxiliary contacts K6 and K8 are used and
connected to the binary inputs 1 and 2 to monitor the status of the fan supplies by the converter. The function of K15 is
described at the next point.
c: Stop mode beside ON/OFF and START/STOP:
This chapter tries to explain the reaction of the drive when the input named EMERGENCY_STOP (906) or COAST_STOP
(905) is operated. Please take the external wiring used for this explanation as an example only!
For EMERGENCY STOP different preconditions have to be taken into account. This description focus on the functionality
and does not take special safety conditions depending on the type of machine into account.
In this case, if emergency stop is hit, the information is transferred to the converter via binary input 5. The converter will
act according to the function programmed (stop by ramp, current limit or coasting). If the converter will not manage to get
the drive to standstill within the time set at K15, the auxiliary contact will switch off the control
power. Because of this the main power contactors K1 and all the others will be switched
off. This may result in failure of components ( see Operating Instructions ). This danger can
be minimized by adding another time delay (grey-shaded parts below). By doing so another
stop mode is available.
- Emergency stop signal initializes the ramp down function inside the converter in that way
described before. If the drive comes to standstill within the time specified by K15, the
converter will switch off the main power contactor K1. If the converter doesn´t manage to
get the drive to standstill within this time, K15 will start the function ELECTRICAL
DISCONNECT with the time delay specified by K16. This information will be transferred to
the converter to a free binary input. This input has to be connected to the COAST_STOP
input of the drive logic. The COAST_STOP input forces the current down to zero as fast as
possible. The delay time of K16 has to be slightly higher than the time needed by the current
controller to get the current to zero. When the time K16 has elapsed the control voltage will
be switched off and all power contactors will drop off.
- If no care should be taken to the speed of the drive the function of K16 can be initialized
by the command ELECTRICAL DISCONNECT.
d: Main contactor handling by the PLC only because of safety reasons:
This mode is not recommended to be used as a standard switch on or switch off sequence. Nevertheless it is sometimes
used to fulfill safety regulations or other needs. In such cases it´s recommended to follow the next guidelines:
- It´s assumed that the PLC´s contact is in serial with the K1 (underneath the terminals named X96: 1 and 2) or in serial
with the auxillary contact of K16 or replaces this one
- Switching off the main power contactor in regenerative mode may result in failure of components (see Operating
Instruction)
- The PLC generates the command "main contactor off". Two types of contacts are needed:
- A pretriggered contact should then be connected to an unused binary input of the converter; this input has to be connected
to the signal START_INHIBIT (908). This will block the controllers, trying to get the current to zero and switch off the main
contactor from the converter point of view (independent, if the converter´s command is used or not).
- A normal contact can then handle the main contactor.
- Caused by the final timing alarms or error may be detected; they should be reset or bypassed (e.g. by the auto reclosing
function
• Sequencing
When the ON command is given to the converter and there is no error signal active, the converter closes the fan, field and
main contactor, checks the supply voltage and the status of the contactors and without error messages, releases the
regulators and starts waiting for the RUN command. When the RUN command is given, the speed reference is released and
speed control mode is active (for more details, see Software Description ).
I 12
3ADW000177R0200_DCS500B_QuickGuide_edisf_b
K16
ELEC.
DISCONN.
1
EMER.
STOP S1
2
K15
CON-2
DIx X6:9
K15
taken from/for further information:
System description
3ADW000066 - chapter 3
K15
K16