
Sigma II User’s Manual
Chapter 3: Wiring
3-17
3.4.4
Interface Circuits
This section shows examples of servo amplifier I/O signal connection to the host control-
ler.
n
Interface for Reference Input Circuits
Analog Input Circuit
Analog signals are either speed or torque reference signals at the impedance below.
•
Speed reference input: About 14k
Ω
•
Torque reference input: About 14k
Ω
The maximum allowable voltage for input signals is ±12V.
Reference Position Input Circuit
An output circuit for the reference pulse and error counter clear signal at the host control-
ler can be either line-driver or open-collector outputs. These are shown below by type.
Line-driver Output Example:
•
Open–collector Output, Example 1: External power supply
12V
25-HP-10B
3
1
2
1000:1
0V
SG
Servo Amplifier
V-REF or
T-REF
1.8k
Ω
(½W) minimum
2k
Ω
About 14k
Ω
Applicable line-driver
SN75174 manufactured by
TI, or the equivalent
Servo amplifier end
Host controller end
150
Ω
4.7k
Ω
2.8V
≤
(High level) - (Low level)
≤
3.7V
VF = 1.5 to 1.8V
Tr1
R1
i
Servo amplifier end
Host
controller end
150
Ω 4.7
k
Ω