beautypg.com

Figure 11. output alarm circuit optically isolated, Output alarm circuit optically isolated, Pf power failure optocoupler timing diagram – KEPCO HSF 600W Series (suffix A and AM) Operator Manuals User Manual

Page 16

background image

14

HSF(A) 600W 101013

NOTE: Unlike earlier (non A) HSF 600W models, –PF and –RC are connected together

and cannot be isolated from each other. This return is connected to the power sup-

ply –OUTPUT when position 4 of SW1 is set to ON (factory default). If it is neces-

sary to isolate the –PF and –RC from the power supply output, set position 4 of

SW1 to OFF.

FIGURE 10. DIP SWITCH SETTINGS FOR OPTICALLY COUPLED LOGICAL ALARM

The logic alarm circuit is a diode transistor optical coupler (see Figure 11). 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 12 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 signal is isolated from the AC input and DC output. The –PF

signal (in common with –RC) is connected to –OUTPUT when position 4 SW1 is set to ON (fac-

tory default). It is possible to isolate both –PF and –RC from –OUTPUT by setting SW1 of position

4 to OFF.

FIGURE 11. OUTPUT ALARM CIRCUIT OPTICALLY ISOLATED

FIGURE 12. ±PF POWER FAILURE OPTOCOUPLER TIMING DIAGRAM

3043770

5

5 +PF

+PF 5

5

SW1

SW2

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

SW1

5

SW2

OFF

ON

ON

OFF

+PF 5

5 +PF

TAB