ABB RER620, Technical Manual

Page: 435 / 584

1MAC309294-MB F
Section 9
Other functions
RER620 429
Technical Manual
The heater will not be energized when operating off battery back up power. For example
if AC power is limited and a pole operation has just occurred, the heater may be switch off
so more available power can go into charging the boost capacitor. This circuit can conduct
and switch 8 amps at 250 Vac continuously.
The heater relay (RA3) is connected to connector W2, pins 7 and 8. If the temperature is
above 27C RA3 is always off. If the temperature is below 20C RA3 is always energized.
If the temperature is between 68°F and 81°F (20°C and 27°C), the state of RA3 is
determined by a rising temperature or a falling temperature. The temperature sensor is
located inside the UPS case, in the corner of the UPS close to the microprocessor.
9.1.3.6 RER620 power
Power to the RER620 is provided by UPS connector W1 pins 7 (+60 Vdc) and 8 (return).
This connection can provide about 30 watts. (In normal operation the RER620 will
consume about 15 watts.) When the UPS is operating from battery power, the supplied
voltage is the battery’s positive voltage. Hence, the voltage range for this power source is
40 Vdc to 60 Vdc.
9.1.3.7 RS485 communications
The communication link between the UPD and the UPS is a half-duplex (2 wires) RS485
serial channel. The UPS RS485 communications link is isolated.
The UPD acts as master, the UPS as slave.
• Transmission speed for the UPD-UPS serial interface (SCI) is fixed at 19200 bps.
• 8 data bits
• No parity
• 1 stop bit