USER'S GUIDE____________________________________________________________________
66 __________________________________________________________________ M210543EN-E
The alarm limits are also used to control the two (pull down) alarm
controls. Control 1 drives, when alarm 1 is on. Control 2 drives, when
alarm 2 is on. Control 3 drives, when alarm 3 is on. The controls are
usually used to drive external relays. For details on relay logic
description, see section Relay Controls on page 40.
Backscatter/contamination control is done by comparing the current
values of backscatter signal with the reference values given with the
CLEAN command. The limits given here are limits for the change in
backscatter signals.
TRANSMITTER CONTAMINATION LIMITS
WARNING LIMIT ( 1.0) 1.5
WARNING LIMIT UPDATED
ALARM LIMIT ( 5.0)
The transmitter values are in volts (V). The measurement range is
0 ... 13 V, where 0 V is a blocked lens. The limit value is given as a
positive value although the signal becomes smaller when contamination
increases. A contamination change of 5 V represents about a 10 %
decrease in the transmitter's lens transmittance (and also a 10 % increase
in visibility indication).
RECEIVER CONTAMINATION LIMITS
WARNING LIMIT ( 200)
ALARM LIMIT ( 500) 600
ALARM LIMIT UPDATED
The receiver values are expressed in hertz (Hz). The measurement range
is 0 ... 10 000 Hz, where 10000 Hz is a blocked lens.
A contamination change of 500 Hz represents about a 10 % decrease in
the receiver's lens transmittance.
ANALOG OUTPUT MODE
0=LINEAR, 1=LN, 2=EXTI, 3=VGI, 4=VG2 ( 4)
ANALOG OUTPUT RANGE
MAX VISIBILITY ( 20000)
= mA ( 20.0)
MIN VISIBILITY ( 10)
= mA ( 4.0)
NOTE
The output above illustrates the response to the command when using
PWD22. The maximum visibility varies according to the product model.
The system responses are otherwise identical.
The analog output modes are explained in section Analog Output Modes
on page 69.
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