Requirements for the connecting cable
1)
Number of wires and shielding
2 wires, shielded
Min. conductor cross section incl. cable end
sleeve with plastic sleeve
0.25 mm
2
Max. conductor cross section incl. cable end
sleeve with plastic sleeve
2.5 mm
2
Max. cable length
2 m
Wiring
Within the control cabinet, shield on PE
1) with connection of an external braking resistor
Tab. 67 Requirements for the connecting cable
Requirements for the shield support with connection of an external braking resistor
•
Place shield of the cable on the device side onto the earthing screw next to the upper slot of the
cooling element.
Selection of suitable external braking resistors
The connected braking resistor must fulfil the following prerequisites:
–
External braking resistors must meet the normative requirements of IEC 61800-5-1.
–
The braking resistor must be designed for operation with high pulse energy during braking.
–
The braking resistor must be suitable for the intermediate circuit voltage that occurs.
–
The resistance value of the braking resistor must be low enough so that the highest braking per-
formance can be absorbed (typically 2 … 2.5 times the nominal output of the motor).
–
The resistance value of the braking resistor must be within the permitted range, so that the brake
chopper in the device is not overloaded. Therefore, use only suitable braking resistors that, with
reference to the voltage, current and pulse energy capacity, are suitable for the power data of the
output stage of the servo drive used.
Technical data for the integrated braking resistor and additional requirements for external braking res-
istors
è
11.3.2 Electrical data for braking resistor (internal/external) [X9B]
Overload protection for external braking resistors
The external braking resistor can be monitored by the firmware of the device with the help of a thermal
model calculation. The CMMT-AS must therefore be parameterised as follows:
–
Activation of external braking resistor
–
Input of the following data: resistance value, continuous power, and permissible impulse energy
When the impulse energy limit is reached, the brake chopper is switched off. If the intermediate circuit
voltage rises again as a result, the output stage switches off with the message “Overload in the inter-
mediate circuit”.
8.11
Cross wiring
Cross wiring permits the design of a device compound, consisting of up to 10 CMMT-AS servo drives.
The following cross wiring options are differentiated:
–
Cross wiring of I/O signals at the connection [X1A]
–
Cross wiring of the mains and logic voltage supply without intermediate circuit coupling
–
Cross wiring of the mains and logic voltage supply with intermediate circuit coupling
Installation
69
Festo — CMMT-AS-C2/C4-3A-... — 2018-02
