Table 13 Control Logic Of Relay Controls 1 And 2; Table 14 Control Logic Of Relay Control 1, 2, And 3 - Vaisala PWD22 User Manual

Chapter 4_________________________________________________________________ Installation
VAISALA ________________________________________________________________________ 51
- RELAY ON DELAY
- RELAY OFF DELAY
The visibility alarm conditions must last the corresponding time in
minutes specified in RELAY ON/OFF DELAY parameter before the
relay control changes. The default delays are five (5) minutes.
Below is a table with a control logic example of relay controls 1 and 2
when the third relay control is driven by hardware status.
Table 13 Control Logic of Relay Controls 1 and 2
States of Relay 1 Corresponding Visibility Conditions
and 2
1 OFF 2 OFF When visibility is higher than LIMIT 1 and LIMIT 2.
1 ON 2 OFF When visibility is lower than LIMIT 1 but higher than
LIMIT 2.
1 ON 2 ON When visibility is lower than LIMIT 1 and LIMIT 2.
Below is a table of a control logic example of relay controls 1 and 2
and 3 when all the relay controls are driven by visibility limits.
Table 14 Control Logic of Relay Control 1, 2, and 3
Relay States
1 OFF 2 OFF 3 OFF
1 ON 2 OFF 3 OFF
1 ON 2 ON 3 OFF
1 ON 2 ON 3 ON
When the third relay control output is set to be driven by the hardware
status, it pulls whenever a hardware alarm is detected For details, see
section System Configuration Commands on page 70.
Corresponding Visibility Conditions
When visibility is higher than all the limits.
When visibility is lower than LIMIT 1 but higher
than LIMIT 2 and LIMIT 3.
When visibility is lower than LIMIT 1 and LIMIT 2
but higher than LIMIT 3.
When visibility is lower than all the limits.