General Instructions Timers
G-68 www.idec.com USA: (800) 262-IDEC or (408) 747-0550, Canada: (888) 317-IDEC
G
Timers
Timing accuracies are calculated from the following formulas:
Repeat Error
Voltage Error
Tv: Average of measured values at voltage V
Tr: Average of measured values at the rated voltage
Temperature Error
Tt: Average of measured values at °C
T20: Average of measured values at 20°C
Setting Error
General Instructions for All Timer Series
oad Current
ith inductive, capacitive, and incandescent lamp loads, inrush current more
han 10 times the rated current may cause welded contacts and other undes-
red effects. The inrush current and steady-state current must be taken into
onsideration when specifying a timer.
ontact Protection
witching an inductive load generates a counter-electromotive force (back
MF) in the coil. The back EMF will cause arcing, which may shorten the con-
act life and cause imperfect contact. Application of a protection circuit is
ecommended to safeguard the contacts.
emperature and Humidity
se the timer within the operating temperature and operating humidity
anges and prevent freezing or condensation. After the timer has been stored
elow its operating temperature, leave the timer at room temperature for a
ufficient period of time to allow it to return to operating temperatures before
se.
nvironment
void contact between the timer and sulfurous or ammonia gases, organic
olvents (alcohol, benzine, thinner, etc.), strong alkaline substances, or strong
cids. Do not use the timer in an environment where such substances are
revalent. Do not allow water to run or splash on the timer.
ibration and Shock
xcessive vibration or shocks can cause the output contacts to bounce, the timer
hould be used only within the operating extremes for vibration and shock resis-
ance. In applications with significant vibration or shock, use of hold down
prings or clips is recommended to secure a timer to its socket.
Time Setting
The time range is calibrated at its maximum time scale; so it is desirable to
use the timer at a setting as close to its maximum time scale as possible. For
a more accurate time delay, adjust the control knob by measuring the operat-
ing time with a watch before application.
Input Contacts
Use mechanical contact switch or relay to supply power to the timer. When
driving the timer with a solid-state output device (such as a two-wire proxim-
ity switch, photoelectric switch, or solid-state relay), malfunction may be
caused by leakage current from the solid-state device. Since AC types com-
prise a capacitive load, the SSR dielectric strength should be two or more
times the power voltage when switching the timer power using an SSR.
Generally, it is desirable to use mechanical contacts whenever possible to
apply power to a timer or its signal inputs. When using solid state devices, be
cautious of inrushes and back-EMF that may exceed the ratings on such
devices. Some timers are specially designed so that signal inputs switch at a
lower voltage than is used to power the timer (models designated as “B"
type).
Timing Accuracy Formulas
= ± 1 x Maximum Measured Value – Minimum Measured Value x 100%
Maximum Scale Value2
= ± Tv - Tr x 100%
Tr
= ± Tt - T20 x 100%
T20
= ± Average of Measured Values - Set Value x 100%
Maximum Scale Value