Rockwell Automation 1771-QC , D17716.5.25 SER/B SERVO POS - Manual (Page 55)

Installing the Assembly
Chapter 6
6Ć5
Selecting Discrete Input Resistance
Select the resistance between each discrete input terminal and the high
side of the input power supply. To select 1.2k ohms, set the switch on. To
select 11.2k ohms, set the switch off. (Figure 6.3)
Figure 6.3
DiscreteĆinputĆresistance Switch Assembly
O
F
F
O
N
1 2 3 4
ON
OFF
ON
OFF
ON
OFF
ON - 1.2k Ω
(pull - up) resistance
OFF - 11.2k
(pull - up) resistance
Hardware
Stop
Jog Forward
(hardware start)
Jog Reverse
(feedrate enable)
Home Limit
Switch
12015
Ω
input
input
With 1.2k ohms, your input device must sink 4mA for a 5V power supply
to 25mA for a 30V power supply. With 11.2k ohms, your input device
must sink 0.5mA for a 5V power supply to 2.7mA for a 30V power
supply.
Unless your input device cannot sink enough current, select 1.2k ohms
because it provides better noise immunity than an 11.2k ohms input
resistance.