Keithley 2010 Service Manual

Memory circuits
ROMs U156 and U157 store the firmware code for instrument operation. U157 stores the
D0-D7 bits of each data word, and U156 stores the D8-D15 bits.
RAMs U151 and U152 provide temporary operating storage. U152 stores the D0-D7 bits of
each data word, and U151 stores the D8-D15 bits.
Semi-permanent storage facilities include NVRAM U136. This IC stores such information as
instrument setup and calibration constants. Data transmission from this device is performed
serially.
RS-232 interface
Serial data transmission and reception is performed by the TXDB and RXDB lines of the
MPU. U159 provides the necessary voltage level conversion for the RS-232 interface port.
IEEE-488 interface
U158, U160, and U161 make up the IEEE-488 interface. U158, a 9914A GPIA, takes care of
routine bus overhead such as handshaking, while U160 and U161 provide the necessary
buffering and drive capabilities.
Analog
Circuitry
(See Figure 4-3)
NVRAM
U136
ROM
U156, U157
RAM
U151, U152
XADTX
XADCLK
XADTS
XADRX
O
P
T
O
I
S
O
ADTX
ADCLK
ADTS
ADRXB
68306
µP
U135
Scan Control
Keypad
Display Board
Controller
Display
DS401
XTAL
Y101
Trigger
U146, U164
Trigger
Link
TRIG IN
TRIG OUT
AT101
U150
U155
IN
OUT
RS-232
U159
Data IN
Data OUT
GPIB
RS-232
Port
IEEE-488
Bus
U158, U160,
U161
U401
Fi
gure
4
-
2
D
igital circuitry block
diagram
Troubleshooting 4-7

Keithley 2010 Specifications

General

Frequency Range	3 Hz to 300 kHz
DC Voltage Range	100 mV to 1000 V
AC Voltage Range	100 mV to 750 V
DC Current Range	3 A
DC Current Accuracy	0.05%
AC Current Range	3 A
Resistance Accuracy	0.01%
Interface	GPIB, RS-232
Power Supply	50 Hz or 60 Hz