GE Timers and Isolation of the PLC System MAIN 222 Industrial Controllers 11/15/2018

Caution with Counters and Timers When using a timer or counter we have a possible problem with switch bounce or multiple counts YOU MAY NEED A ONE SHOT this will only allow for a single increment not multiple 11/15/2018

Timers ON-Delay if you want to program a time delay before an instruction becomes true Normal Timer Off-Delay off-delay timer increments while no accumulator is present, and resets to 0 when there is an accumulator. Time may be counted in tenths of seconds or hundredths of seconds, or thousandths of seconds, depending on the time-base. The range for this timer is 0 to +32,767 time units. When there is an accumulator available to the off-delay timer, it sets CV to 0. If the accumulator is removed from the function, the timer starts incrementing CV. 11/15/2018

Timer OFF example In this example, an Off Delay Timer is used to turn off an output (%Q00001) whenever an input (%I00001) turns on. The output is turned on again 5.0 seconds after the input goes off. Note: CV (the current value) does not display on the 90-30 version of this function. Variable Declaration Name Type Length Reference %I00001 BOOL 1 %I00001 %Q00001 BOOL 1 %Q00001 %R00004 OFDT_TENTHS 1 %R00004 11/15/2018

ON Timer Example In this example, an On Delay Stopwatch timer is used to create a signal (%Q00011) that turns on 8.0 seconds after %Q00010 turns on, and turns off when %Q00010 turns off. Note: CV (the current value) does not display on the 90-30 version of this function. Variable Declaration Name Type Length Reference %Q00010 BOOL 1 %Q00010 %Q00011 BOOL 1 %Q00011 %R00001 ONDTR_TENTHS 1 %R00001 11/15/2018

Addressing A Timer The Input The Reset The PV This is the location where the change of state is observed (can be from an actual input, other function ie counter or and output) The Reset An address that confirms resetting the PV (preset value) back to its original value. Note that we can “lock” the counter out if the reset input is forced ON The PV The Preset value is the address numerically after the counter number If we have %R2 as a counter then %R3 is the PV registry Highest Number is 32767 11/15/2018

Special Note We have to have an ALWAYS_ON in series with the INPUT rung to COUNTERS and TIMERS on the Series 90 Micros. 11/15/2018

Where to Get More Information See Web Site VersaPro 2.02/3 users guide Series 90 Micro Workshop Believe it or not the help in VersaPro Timer Function (Versa Mas Series 90-30) 11/15/2018

Input / Output Isolation Why Isolate ? Isolate What? The PLC is a messenger of allowing on or off a signal Its job is not to provide current, voltage Need to separate the high voltage side from internal side of PLC 11/15/2018

Input Isolation 11/15/2018

Output Module 11/15/2018