IDEC MICRO3 User Manual

4: SPECIAL FUNCTIONS
4-18 USER’S MANUAL
External Analog Timer
Analog timer unit PFA-1U11 can be connected to MICRO
3
to be used as an external analog timer and the preset value can
be adjusted in very small increments from the panel front.
Analog Timer Unit PFA-1U11
The analog timer unit generates output pulses of approximately 80 msec and the interval
can be changed between 20 msec and 2 sec using the knob on the analog timer unit.
Measuring Analog Timer OFF Duration
Connect the output of the analog timer unit to an input terminal of MICRO
3
and measure the OFF duration of the analog
timer output using a timer instruction. The OFF duration can be varied using the knob on the analog timer unit. The reso-
lution of the timer preset value depends on the first timer instruction TIM (100-msec timer), TMH (10-msec timer), or
TMS (1-msec timer) used for measuring the OFF duration. Use the measured OFF duration as a preset value of another
timer instruction.
The preset value of the timer instruction for measuring the OFF duration must be the same as operand S1 of the SUB (sub-
traction) instruction. The first line and the second line of the program above must be in this order. If reversed, the measured
duration cannot be set to the preset value for the analog timer Tn correctly.
The value of Dn is set to the preset value of the analog timer approximately 2 seconds after the program is started or the
knob setting on the analog timer unit is changed.
Preset value Dn for the analog timer depends on the resolution of the timer instruction used for measuring the OFF dura-
tion. The maximum preset value also varies with the input filter preset value of
MICRO
3
and ambient temperature.
Depending on the combination of timer instructions used for measuring the OFF duration and for time-delay operation,
available time delay ranges are shown below.
Note: When the TIM (100-msec timer) instruction is used for measuring the OFF duration, do not set the control knob of
the analog timer unit to the minimum, because the TIM instruction cannot measure the minimum OFF duration of 20
msec. Set the control knob to make sure that the TIM instruction can measure the output pulse OFF duration.
Timer instruction
for measuring OFF
duration
Measurement
resolution
Preset value Dn
for analog timer
Time delay range of analog timer
TIM TMH TMS
TIM 100 msec 1 to 20 (Note) 0.1 to 2 sec 10 to 200 msec 1 to 20 msec
TMH 10 msec 2 to 200 0.2 to 20 sec 20 msec to 2 sec 2 to 200 msec
TMS 1 msec 20 to 2000 2 to 200 sec 0.2 to 20 sec 20 msec to 2 sec
Output Pulse
ON
OFF
Approx. 20 msec to 2 sec
variable80 msec
I1
When the output pulse of the external analog timer unit is
turned on (input I1 is turned on), timer current value Tm
is subtracted from 9999 and the result is set to data regis-
ter Dn. Dn is used as a preset value of timer instruction
Tn (analog timer).
When the output pulse is off (input I1 is off), the 10-msec
timer TMH times down from 9999 to measure the OFF
duration of the external analog timer unit output.
When input I0 is on, the analog timer Tn starts to time
down from the preset value Dn.
SUB S1
9999
REP
**
SOTU
S1
Tm
D1
Dn
I1: Pulse output from the external analog timer unit
Tm: Current value of timer TMHm
Dn: Preset value for the analog timer Tn
THm
9999
I1
I0
Tn
Dn

IDEC MICRO3 Specifications

General

Brand	IDEC
Model	MICRO3
Category	Controller
Language	English