Milldrone, you were exactly correct when you said "The sealin branch would keep the output on after the initial low speed start" How can I automatically reset/silence the alarm when there is not an alarm condition in the attached ladder program?
First we need to credit Bernie Carlton for spotting the latch/sealin issue. He saw that potential problem on Oct 8 th 2014.
try this version
PLC 05
// Rung 1
// Address 0
#BEGIN COMMENT
"This should select mode 60 as the HSIO mode, and set the filter time for inputs X1 and X2 "
"at 0 ms"
#END
STR SP0
LD K60
OUT V7633
LD K6
OUT V7635
LD K6
OUT V7636
// Rung 2
// Address 7
#BEGIN COMMENT
"The shaft monitored by X2 is rotating at 3150 rpm at full speed. The prox target is 1/2 of "
"1 revolution, meaning the prox is closed for 1/2 of a revolution. I need the alarm to sound "
"if it slows to about 2500 RPM or less. The prox is Automation Direct # AM1-AP-1H with "
"2khz switching frequency. The PLC is a Direct Logic 05 series D0-05DR-D"
#END
STR X0
AND X2
TMRF T2 K3
// Rung 3
// Address 12
#BEGIN COMMENT
"3150 rpm/60=52.5 rotations per second. 1 sec/52.5 rotations = .019 seconds per "
"rotation, so I set the timers to 3, is this correct? "
""
"With the timers set to 3, the alarm sounded when I engaged the machine from a stop, and "
"continued to annoy me with its buzzing until I switched the PLC into STOP mode. If I then "
"switch it back to TERM or RUN mode while the machine is running, the alarm will only "
"sound when I throttle it down to idle..... So I think I need a timer in this rung to only allow "
"the alarm to sound for a second when an alarm condition is present, then turn the alarm "
"off until an alarm condition is present again."
#END
STR X0
ANDN X2
TMRF T3 K3
// Rung 4
// Address 17
#BEGIN COMMENT
"I am not using an alarm reset, if an alarm condition is present, the operator simply needs to "
"shut the machine down, which opens the engage switch X0, silencing the alarm. If the "
"operator continues to run the machine with an anoying alarm, they will be tasked with "
"hours of crawling inside the combine to remove the tough wet soybean stalks piled "
"upstream of the stalled chopper. Been there done that, not fun at all."
#END
STR X0
ANDN C0
OUT Y0
// Rung 5
// Address 20
#BEGIN COMMENT
"This rung adds a ""warble to the alarm"" as Lancie suggested."
#END
STR X0
AND Y0
ANDN T4
TMR T4 K12
AND TA4 K6
OUT C0
// Rung 6
// Address 29
END
// Rung 7
// Address 30
NOP
#BEGIN ELEMENT_DOC
"UW0","K2.5","",""
"X0","","","Engage Switch"
"X1","","","Rethresh Prox"
"X2","","","Chopper Prox"
"Y0","","","Alarm"
"C0","AlarmWarble","",""
"T2","","","X2 ON Timer"
"T3","","","X2 OFF Timer"
"T4","","","alarm warble"
"T5","","","Alarm Off Time"
"TA4","AlarmWarbleAcc","",""
"SP5","_100MilliSeconds","","Filtered inputs"
#END