Keithley 7037, Instruction Manual

Page: 53 / 72

Service Information
6-10
Principles of operation
The following paragraphs discuss the basic operating princi-
ples for the Model 7037 and can be used as an aid in trouble-
shooting the card. The schematic drawings of the card are
shown on drawing numbers 7037-106 and 7021-172 located
in Section 7.
Block diagram
Figure 6-7 shows a simplified block diagram of the
Model 7037. Key elements include the ROM, which contains
card ID and configuration information, relay drivers and
relays, digital I/O output channel drivers, and digital I/O
input channel registers. These various elements are discussed
in the following paragraphs.
Figure 6-7
Model 7037 block diagram
To Mainframe
OUTCLOCK
OUTDATA
STROBE
ENABLE
Relay
Drivers
U106-
U109
Relay
Channels
1-30
User
connections
IDCLK
IDDATA
ROM
U110
+3.5V (Steady State)
+5.7 (
≈
100 msec during
relay actuation)
Relay
Power
Control
Q100, Q101
U114, U115
+6V, +15V
To/From
Mainframe
To Mainframe
OUTCLOCK
OUTDATA
STROBE
ENABLE
Output
Channel
Drivers
U105
and
U106
Output
Channels
31-40
From
Mainframe
INDATA
INCLOCK
STROBE
ENABLE
Input
Channel
Registers
U101
and
U102
IN 1
IN 2
IN 10
User
connections