Zenith Z-100 PC series Service Manual page 334

2.2 SIGNAL INTERFACE
The signal interface consists of two categories:
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a. Control Lines
b. Data Transfer Lines
All lines in the signal interface are digital in nature and either provide signals to the drive (input). or provide signals
to the host (output). via interface connector Pl/J1.
2.2.1 Input Lines
The input signals are of three types: those intended to be multiplexed in a multiple drive system. those which will
perform the multiplexing. and those signals which are not multiplexed and affect all the drives in a daisy chain
system.
The input signals to be multiplexed are:
a. DIRECTION SELECT
b. STEP
c. WRITE DATA
d. WRITE GATE
e. SIDE SELECT
The input signals which are intended to do the multiplexing are:
a. DRIVE SELECT 1
b. DRIVE SELECT 2
c. DRIVE SELECT 3
d. DRIVE SELECT 4
MOTOR ON is not mUltiplexed.
The input lines have the following electrical specifications. See figure 2·2 for the recommended circuit.
True
=
Logical zero
=
Vin ± 0.0 to
+
0.4 V @ lin
=
40 rnA (max)
False
=
Logical one
=
Vin
+
2.5 to
+
5.25 V @ lin
=
250 Jl.A (open)
Input impedance = 150 ohms
+5V
~
150
n
RIBBON OR
----i
MAX 10 FEET
TWISTED PAIR
39238·10
FIGURE 2·2. INTERFACE SIGNAL DRIVER/RECEIVER
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2·2
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