12
HSF 600W 042315
3.7.2 ALARM SIGNALS.
Either of two options are available for signalling alarms: isolated relay contacts (factory default,
PAR. 3.7.2.1) or logic level alarm signals ±PF (PAR. 3.7.2.2). The ±PF logic level alarm option
must be used if the power supply is intended to operate below the minimum voltages listed in
Table 4.
3.7.2.1 INTERNAL ISOLATED RELAY ALARM
The first option, the factory default setting, uses an isolated internal relay offering normally closed
(NC) and normally open (NO) contacts referenced to an isolated common (AL COM). These con-
tacts may be used to configure “close on failure” or “open on failure” alarm circuits. (Refer to the
Series RA 19-4C Manual for alarm configurations for multiple HSF power supplies.) Setting posi-
tions 5 and 6 of the DIP switches as shown in Figure 9A selects this option. The NC (pin 6 of the
rack adapter I/O connector) and NO (pin 7) signals are referenced to Alarm common (pin 14).
3.7.2.2 OPTICALLY-COUPLED LOGICAL ALARM
The second option uses optically-coupled logic level alarm signals, +PF (pin 5 of the rack adapter
I/O connector) and -PF (pin 13), provided directly from the Kepco RKW power supply that is the
heart of the HSF. This option is selected by setting positions 5 and 6 of the DIP switches as shown
in Figure 9B. Use this option if the power supply will operate below the minimum voltages speci-
fied in Table 4.
FIGURE 9. DIP SWITCH SETTINGS FOR OPTICALLY COUPLED LOGICAL ALARM
The logic alarm circuit is a diode transistor optical coupler (see Figure 10). The transistor is nor-
mally conducting. When the alarm is activated upon detection of power loss, overvoltage, fan
fault, overtemperature or overcurrent condition, the transistor cuts off and the collector emitter cir-
cuit is open. Figure 11 is a timing diagram of the power fail signal.
The default state of the alarm is logic low. The sink current for the optocoupler is 50mA maximum,
the maximum collector to emitter saturation voltage is 0.40 Volts, and the collector to emitter volt-
age is 40 volts maximum. The PF signals are isolated from the AC input and DC output.
3042878
5
5 +PF
+PF 5
5
SW1
-PF 6
6
SW2
6
6 -PF
OFF
ON
OFF
ON
USE N.O. AND N.C CONTACTS
(FACTORY DEFAULT)
OF INTERNAL RELAY
A
LOGICAL ALARM
USE OPTICALLY-COUPLED
B
(+PF AND -PF)
5
6
6
SW1
5
SW2
OFF
ON
ON
OFF
+PF 5
-PF 6
6 -PF
5 +PF
TAB
