Honeywell VC4 User Manual page 167

Status - 1 byte
0x00 = packet accepted
0x01 = internal filter lifetime unacceptable
0x02 = external filter lifetime unacceptable
0xFF = slave in monitor, unable to accept changes
Get Duty Cycle - 0x69
This command allows the master to find out the minimum window time and the monitor relay
action during duty cycle bits on a slave.
The minimum window time (or duty cycle) defaults to zero seconds. But it may be set larger to
conserve tape in installations that have some concentration of gas for long periods of time. The
tape will not advance until the minimum window time has accumulated even if the tape is
saturated. During periods when the tape is saturated but prevented from advancing, the VC4™
will continue to report the most recent concentration reading. Unfortunately it will not be able
to detect any changes in concentration during this period because the tape is saturated.
By default, the monitor relay (RY6) will energize when monitoring is temporarily suspended
because of tape saturation. However this reaction can be inhibited for individual points. The
monitor relay action during duty cycle bits default to TRUE but can be set to FALSE via either
the keypad or serial packet 0x65, Set Duty Cycle.
Command Packet to slave:
Command code (0x69) - 1 byte
Response from slave:
Command code (0x69) - 1 byte
VC4™ date 2 bytes
VC4™ time 2 bytes
Bits permitting monitor relay action during Duty cycle - 1 byte
bit 0 point1
bit 1 point2
bit 2 point3
bit 3 point4
bits 4-7 unused (always 0)
Min window time (seconds) - 2 byte
Status - 1 byte (always 0x00)
VC4™ 167 User Manual