Harris Platinum HT EL 2000LS Technical Manual

Harris Platinum HT EL 2000LS Technical Manual Manual pdf 43 page image

where it is compared with a user set power value to cause theoutput power to foldback. Normally the visual is set to startfoldback at 1.2:1 VSWR reflected power and the aural for a 1.6:1VSWR reflected power.4.4.3 High VSWRThese circuits compare the visual and aural reflected powersamples to a user set power value. If the sample exceeds the uservalue the HIGH VSWR indicator is turned on. This point isnormally set for 1.5:1 VSWR visual and 1.8:1 for aural. Each PAmodule also monitors the VSWR and will fault if module re-flected power exceeds 90 watts.The hi VSWR circuit has an option jumper which if selected(JP16, 1 to 2) will turn off the transmitter when the set point isexceeded. The transmitter will remain off until the transmitterOFF button is pressed to clear the HI VSWR fault indicator.If JP16 is in the 2 to 3 position a HI VSWR fault will be indicatedbut the transmitter will remain on air until module VSWR faultoccurs.4.4.4 Command Input Logic PAL U8 (917-2321-004)The command input logic PAL U8 interfaces the LOCAL andREMOTE command inputs. When the LOCAL mode is selectedall REMOTE commands are inhibited.See Table 4-3 for U8 Input and Output Functions4.4.4.1 XMTR CTRL PAL U15The XMTR CTRL PAL U15 (917-2321-007) provides the logicto interface with the rf modules, power supply, video loss timerand fault indicators.See Table 4-4 for U15 Input & Output Functions4.4.4.2 Fault Encoder U19 (917-2321-008)This PAL is used to combine input signals to produce outputs asdetailed below.See Table 4-5 for U19 Input & Output Functions4.4.4.3 50V OKThis circuit monitors the 50 volt supply and the comparatoroutput will go low when the supply reaches 48 volts. At this pointthe modules can be enabled and the transmitter is operational.INPUTSPIN NO. NAME FUNCTION1 CLK Clock register2 ON Local transmitter ON command3 OFF Local transmitter OFF command4 LOCAL Local mode of control5 SPARE_INPUT Not used6 INT_LOC External interlock7 AUR_LOWER Remote aural lower command8 AUR_RAISE Remote aural raise command9 VIS_LOWER Remote visual lower command10 VIS_RAISE Remote visual raise command11 RMT_OFF Remote transmitter off command13 RMT_ON Remote transmitter on commandOUTPUT LOGIC STATES14 MOD_FLT_RST USED to reset modules, pin goes high for: A) Transmitter ON button is pressed,B) RMT_ON command is active,C) LOSS_RESET is active.15 !TX_ON Used to latch XMTR ON condition. pin goes low for: A) TXON is low and TXOFF is highb) SEL_REMOTE, EXT_INTERLOCK, TX_OFF, RMT_TX_OFF are high and RMT_TX_ON is low.16 !TX_OFF Used to turn transmitter off.17 INTERLOCK Used by EXT INT_LOC to inhibit AC mains to the 50 volt supply if interlock is not closed.Pin 17 is high if EXT INT_LOCK is low.18 !LOCAL Used to inhibit all remote inputs if LOCAL switch is pushed to on. Sets pin 18 low ifSEL_REMOTE is low.19 VIS_RAISE Enables remote visual raise command20 !VIS_LOW Enables remote visual lower command21 !AUR_RAISE Enables remote aural raise command22 !AUR_LOWER Enables remote aural lower commandTable 4-3. U8 Input & Output FunctionsSection IV - Theory of OperationRev. B: 7/15/02 888-2457-001 4-5WARNING: Disconnect primary power prior to servicing.