Mitsubishi Electric Q170MSCPU User Manual page 204

6 INSPECTION AND MAINTENANCE
Do not mistake the polarity and " + / - " of diode, as this may lead to destruction or damage.
(b) Calculate the connecting resistor value R as indicated below.
To satisfy the 0.9 [mA] OFF current of the Motion controller, the resistor R to
be connected may be the one where 3.1 [mA] or more will flow.
I : Iz = Z(Input impedance): R
R
Iz
R × Z(Input impedance) =
I
R
R < 1625 [ ]
Assuming that resistor R is 1500 [ ], the power capacity W of resistor R is:
W = (Input voltage)
(c) The power capacity of the resistor selected is 3 to 5 times greater than the
actual current consumption. 1.5K [ ], 2 to 3 [W] resistor may therefore be
connected to the terminal in question.
(2) Internal output circuit troubleshooting
The following describes possible problems with internal output circuits and their
corrective actions.
A lamp, relay or photocoupler can be driven. Install a diode(D) for an inductive
load (relay etc.), or install an inrush current suppressing resistor(R) for a lamp
load. (Permissible current: 40mA or less, inrush current: 100mA or less)
A maximum of 2.6V voltage drop occurs in the servo amplifier.
(a) Circuit example of sink output
(b) Circuit example of source output
0.9
3.1 × 5.6 × 10
2 2
÷ R = 26.4 ÷ 1500 = 0.464 [W]
If polarity of diode is reversed,
Motion controller will fail.
Load
24VDC 10%
If polarity of diode is reversed,
Motion controller will fail.
Load
24VDC 10%
CAUTION
6 - 37
3
= 1625[ ]