SRS Labs SIM922 Operation manual

Operation and Service Manual
Diode Temperature Monitor
SIM922
Stanford Research Systems
Revision 1.5 •September 17, 2010

Certification
Stanford Research Systems certifies that this product met its published specifications at the time
of shipment.
Warranty
This Stanford Research Systems product is warranted against defects in materials and workman-
ship for a period of one (1) year from the date of shipment.
Service
For warranty service or repair, this product must be returned to a Stanford Research Systems
authorized service facility. Contact Stanford Research Systems or an authorized representative
before returning this product for repair.
Information in this document is subject to change without notice.
Copyright c Stanford Research Systems, Inc., 2003, 2010. All rights reserved.
Stanford Research Systems, Inc.
1290–D Reamwood Avenue
Sunnyvale, CA 94089 USA
Phone: [phone] •Fax: [phone]
www.thinkSRS.com •e-mail: [email protected]
Printed in U.S.A. Document number 9-01556-903
SIM922 Diode Temperature Monitor

Contents
General Information iii
Service .............................. iii
Symbols ............................. iv
Notation ............................. v
Specifications .......................... vi
1 Getting Started 1 – 1
1.1 Introduction to the Instrument . . . . . . . . . . . . . 1 – 2
1.2 Front-Panel Operation . . . . . . . . . . . . . . . . . . 1 – 2
1.3 Sensor Interface . . . . . . . . . . . . . . . . . . . . . . 1 – 3
1.4 SIMInterface........................ 1–5
2 Remote Operation 2 – 1
2.1 Index of Common Commands . . . . . . . . . . . . . . 2 – 2
2.2 Alphabetic List of Commands . . . . . . . . . . . . . . 2 – 4
2.3 Introduction ........................ 2–6
2.4 Commands......................... 2–7
2.5 StatusModel........................ 2–17
i

ii Contents
SIM922 Diode Temperature Monitor

General Information
The SIM922 Diode Temperature Monitor, part of Stanford Research
Systems’ Small Instrumentation Modules family, consists of four
channels of sensor excitation and readout for precision low-noise
diode thermometry. Independent 10 µA DC current sources provide
sensor excitations to the four-wire measurement circuits.
Service
Do not install substitute parts or perform any unauthorized modifi-
cations to this instrument.
The SIM922 is a single-wide module designed to be used inside the
SIM900 Mainframe. Do not turn on the power until the module is
completely inserted into the mainframe and locked in place.
iii

iv General Information
Symbols you may Find on SRS Products
Symbol Description
Alternating current
Caution - risk of electric shock
Frame or chassis terminal
Caution - refer to accompanying documents
Earth (ground) terminal
Battery
Fuse
On (supply)
Off (supply)
SIM922 Diode Temperature Monitor

General Information v
Notation
The following notation will be used throughout this manual:
•Front-panel buttons are set as [Button];
[Adjust ] is shorthand for “[Adjust ] & [Adjust ]”.
•Front-panel indicators are set as Overload.
•Remote command names are set as *IDN?.
•Literal text other than command names is set as OFF.
SIM922 Diode Temperature Monitor

vi General Information
Specifications
Performance Characteristics
Min Typ Max Units
Inputs Number of inputs 4
Sensor type Silicon diode
Measurement type 4–wire
Excitation constant current
9.999 10 10.001 µA DC,
±5 ppm/◦C
Sensor Characteristics Sensor units Volts
Input Range 0 2.5 V
sensor+lead resistance 1400 Ω
Calibration curves 1 built-in
4 user defined curves
Curve size (each) 256 points
Temperature range 1.4 475 K (typical)
sensor dependent
Measurement Display resolution 4 digits
Interface resolution 1 µV
1 mK
Measurement resolution 1.2 µV rms
Measurement accuracy, (23 ±1)◦C 20 µV+0.01 %
Temperature coefficient −5+5 ppm/◦C
Operating Temperature 0 40 ◦C
Power ±15,+5 V DC
Supply current 50 (±15 V), 250 (+5 V) mA
General Characteristics
Interface Serial (RS-232) through SIM interface
Connectors 2 DB–9 (female)
4–wire measurement +ground (Ch 1 & 2)
4–wire measurement +ground (Ch 3 & 4)
DB–15 (male) SIM interface
Weight 1.4 lbs
Dimensions 1.500 W×3.600 H×7.000 D
SIM922 Diode Temperature Monitor

1 Getting Started
This chapter gives you the necessary information to get started
quickly with the SIM922 Diode Temperature Monitor.
In This Chapter
1.1 Introduction to the Instrument . . . . . . . . . . . . . 1 – 2
1.1.1 Overview ..................... 1–2
1.2 Front-Panel Operation . . . . . . . . . . . . . . . . . . 1 – 2
1.2.1 Excitation ..................... 1–3
1.2.2 Units........................ 1–3
1.3 Sensor Interface . . . . . . . . . . . . . . . . . . . . . . 1 – 3
1.3.1 Four-wire measurement . . . . . . . . . . . . . 1 – 4
1.3.2 Two-wire measurement . . . . . . . . . . . . . 1 – 4
1.4 SIMInterface ....................... 1–5
1.4.1 SIM interface connector . . . . . . . . . . . . . 1 – 5
1.4.2 Direct interfacing . . . . . . . . . . . . . . . . . 1 – 5
1–1

1–2 Getting Started
1.1 Introduction to the Instrument
The SIM922 Diode Temperature Monitor monitors up to four (4)
silicon diode thermometers using a precision 10 µA DC current exci-
tation.
1.1.1 Overview
Each channel has an independent, precision 10 µA current source,
so the excitation to the user’s sensor remains steady as the SIM922
cycles between measurements. Disabling a channel switches that
channel’s current source off.
A precision 24–bit analog-to-digital converter is cycled between the
channels with a rate of 4 conversions per second. With all channels
enabled, a complete cycle is completed every second; disabling some
channels yields a corresponding increase in overall cycle rate.
1.2 Front-Panel Operation
The front panel of the SIM922(see Figure 1.1) provides a simple op-
erator interface.
Figure 1.1: The SIM922 front and rear panels.
SIM922 Diode Temperature Monitor

1.3 Sensor Interface 1–3
1.2.1 Excitation
The four channels of the SIM922 Diode Temperature Monitor can be
independently enabled or disabled from the front panel. Disabling
a channel turns offthe 10 µA excitation current to that sensor, and
speeds the readout rate for the remaining (enabled) channels.
To toggle the excitation for a channel, first briefly press [Excitation].
One of the four channel displays will appear highlighted, indicating
which channel is selected. Briefly tap [Excitation] to advance the
highlighted selection until the desired channel is selected. Then
depress and hold [Excitation] until the display switches between the
numerical value and the word .
1.2.2 Units
The SIM922 displays the sensor results either as voltage (in millivolts)
or temperature (in kelvin). Pressing [Units] toggles between these
two modes; the active units are indicated by the illuminated Kor
mV.
When temperature units are selected, a sensor calibration curve is
required. The SIM922 is preprogrammed with a standard curve for
Si diode sensors. Each channel also has non-volatile memory to store
a separate sensor curve with up to 256 temperature-vs-resistance
points. The actual curve to use is selected with the remote interface
CURV command.
1.3 Sensor Interface
The sensor interface on the SIM922 consists of two rear-panel DB–9/F
connectors, labeled “CHANNELS 1 & 2” and “CHANNELS 3 & 4”
(see Figure 1.1). Both connectors follow the same pinout, given in
Table 1.1
Pin Signal
1 I+, Ch 1(3)
2 I−, Ch 1(3)
3 ground
4 I+, Ch 2(4)
5 I−, Ch 2(4)
6 V+, Ch 1(3)
7 V−, Ch 1(3)
8 V+, Ch 2(4)
9 V−, Ch 2(4)
Table 1.1: SIM922 Sensor Interface Connector Pin Assignments, DB–9
SIM922 Diode Temperature Monitor

1–4 Getting Started
1.3.1 Four-wire measurement
To avoid sensitivity to wiring lead resistance, the SIM922 is config-
ured for four-wire measurements. The basic circuit for this wiring
scheme is shown in Figure 1.2.
V+
Sensor
V–
I–
I+
Figure 1.2: Wiring diagram for four-wire readout.
1.3.2 Two-wire measurement
If application-specific constraints limit the number of leads to the
sensor, the SIM922 can be wired to measure the sensor resistance
with a simple two-wire circuit, shown in Figure 1.3. Note that the
lead resistance (past the junction points of the current and voltage
leads) will add as a direct resistance error when measuring the sensor.
V+
Sensor
V–
I–
I+
Figure 1.3: Wiring diagram for two-wire readout.
SIM922 Diode Temperature Monitor

1.4 SIM Interface 1–5
1.4 SIM Interface
The primary connection to the SIM922 Diode Temperature Monitor is
the rear-panel DB–15 SIM interface connector. Typically, the SIM922
is mated to a SIM900 Mainframe via this connection, either through
one of the internal mainframe slots, or the remote cable interface.
It is also possible to operate the SIM922 directly, without using the
SIM900 Mainframe. This section provides details on the interface.
The SIM922 has no internal protection against reverse polarity, missing
CAUTION supply, or overvoltage on the power supply pins. Misapplication of power
may cause circuit damage. SRS recommends using the SIM922 together
with the SIM900 Mainframe for most applications.
1.4.1 SIM interface connector
The DB–15 SIM interface connector carries all the power and commu-
nications lines to the instrument. The connector signals are specified
in Table 1.2
Direction
Pin Signal Src ⇒Dest Description
1 SIGNAL GND MF ⇒SIM Ground reference for signal
2−STATUS SIM ⇒MF Status/service request (GND=asserted, +5V=idle)
3 RTS MF ⇒SIM HW Handshake (+5 V=talk; GND=stop)
4 CTS SIM ⇒MF HW Handshake (+5 V=talk; GND=stop)
5−REF 10MHZ MF ⇒SIM 10 MHz reference (optional connection)
6−5V MF ⇒SIM Power supply (No connection in SIM922)
7−15V MF ⇒SIM Power supply (analog circuitry)
8 PS RTN MF ⇒SIM Power supply return
9 CHASSIS GND Chassis ground
10 TXD MF ⇒SIM Async data (start bit=“0”=+5 V; “1”=GND)
11 RXD SIM ⇒MF Async data (start bit=“0”=+5 V; “1”=GND)
12 +REF 10MHz MF ⇒SIM 10 MHz reference (optional connection)
13 +5V MF ⇒SIM Power supply (digital circuitry)
14 +15V MF ⇒SIM Power supply (analog circuitry)
15 +24V MF ⇒SIM Power supply (No connection in SIM922)
Table 1.2: SIM Interface Connector Pin Assignments, DB-15
1.4.2 Direct interfacing
The SIM922 is intended for operation in the SIM900 Mainframe, but
users may wish to directly interface the module to their own systems
without the use of additional hardware.
SIM922 Diode Temperature Monitor

1–6 Getting Started
The mating connector needed is a standard DB–15 receptacle, such as
Amp part # 747909-2 (or equivalent). Clean, well-regulated supply
voltages of +5, ±15 VDC must be provided, following the pin-out
specified in Table 1.2. Ground must be provided on pins 1 and 8,
with chassis ground on pin 9. The −STATUS signal may be monitored
on pin 2 for a low-going TTL-compatible output indicating a status
message.
1.4.2.1 Direct interface cabling
If the user intends to directly wire the SIM922 independent of the
SIM900 Mainframe, communication is usually possible by directly
connecting the appropriate interface lines from the SIM922 DB–15
plug to the RS-232 serial port of a personal computer.1Connect RXD
from the SIM922 directly to RD on the PC, TXD directly to TD, and
similarly RTS→RTS and CTS→CTS. In other words, a null-modem
style cable is not needed.
To interface directly to the DB–9 male (DTE) RS-232 port typically
found on contemporary personal computers, a cable must be made
with a female DB–15 socket to mate with the SIM922, and a female
DB–9 socket to mate with the PC’s serial port. Separate leads from
the DB–15 need to go to the power supply, making what is sometimes
know as a “hydra” cable. The pin-connections are given in Table 1.3.
DB–15/F to SIM922 Name
DB–9/F
3→ 7 RTS
4→ 8 CTS
10 → 3 TxD
11 → 2 RxD
5 Computer Ground
to P/S
7→ −15 VDC
14 → +15 VDC
13 → +5 VDC
8,9 → Ground (P/S return current)
1→ Signal Ground (separate wire to Ground)
Table 1.3: SIM922 Direct Interface Cable Pin Assignments
1Although the serial interface lines on the DB-15 do not satisfy the minimum
voltage levels of the RS-232 standard, they are typically compatible with desktop
personal computers
SIM922 Diode Temperature Monitor

1.4 SIM Interface 1–7
1.4.2.2 Serial settings
The initial serial port settings at power-on are: 9600 Baud, 8–bits, no
parity, 1 stop bit, and RTS/CTS flow control. These may be changed
with the BAUD,FLOW, or PARI commands.
The maximum standard baud rate that the SIM922 supports is 38400.
The minimum baud rate is 110. Above 38400, the SIM922 can be
set to the following (non-RS-232-standard) baud rates: 62500, 78125,
104167, 156250. Note that these rates are typically not accessible on
a standard PC RS-232 port, but can be used between the SIM922 and
the SIM900 Mainframe.
SIM922 Diode Temperature Monitor

1–8 Getting Started
SIM922 Diode Temperature Monitor

2 Remote Operation
This chapter describes operating the SIM922 over the serial interface.
In This Chapter
2.1 Index of Common Commands . . . . . . . . . . . . . 2 – 2
2.2 Alphabetic List of Commands . . . . . . . . . . . . . 2 – 4
2.3 Introduction........................ 2–6
2.3.1 Power-on configuration . . . . . . . . . . . . . 2 – 6
2.3.2 Buffers ....................... 2–6
2.3.3 Device Clear . . . . . . . . . . . . . . . . . . . . 2 – 6
2.4 Commands ........................ 2–7
2.4.1 Command syntax . . . . . . . . . . . . . . . . . 2 – 7
2.4.2 Notation...................... 2–8
2.4.3 Readout commands . . . . . . . . . . . . . . . 2 – 9
2.4.4 Excitation commands . . . . . . . . . . . . . . 2 – 9
2.4.5 Display & configuration commands . . . . . . 2 – 10
2.4.6 Sensor calibration commands . . . . . . . . . . 2 – 10
2.4.7 Serial communication commands . . . . . . . 2 – 11
2.4.8 Status commands . . . . . . . . . . . . . . . . . 2 – 12
2.4.9 Interface commands . . . . . . . . . . . . . . . 2 – 13
2.5 StatusModel ....................... 2–17
2.5.1 Status Byte (SB) . . . . . . . . . . . . . . . . . . 2 – 18
2.5.2 Service Request Enable (SRE) . . . . . . . . . . 2 – 19
2.5.3 Standard Event Status (ESR) . . . . . . . . . . 2 – 19
2.5.4 Standard Event Status Enable (ESE) . . . . . . 2 – 20
2.5.5 Communication Error Status (CESR) . . . . . . 2 – 20
2.5.6 Communication Error Status Enable (CESE) . 2 – 21
2.5.7 Overload Status (OVSR) . . . . . . . . . . . . . 2 – 21
2.5.8 Channel Status Enable (OVSE) . . . . . . . . . 2 – 21
2–1

2–2 Remote Operation
2.1 Index of Common Commands
symbol definition
i,jIntegers
f,gFloating-point values
cChannel number (0–4); c=0 means “all”
zLiteral token
sArbitrary character sequence (no “,” or “;”)
(?) Required for queries; illegal for set commands
var Parameter always required
{var}Required parameter for set commands; illegal for queries
[var] Optional parameter for both set and query forms
Readout
VOLT? c[,n]2 – 9 Voltage Value
TVAL? c[,n]2 – 9 Temperature Value
SOUT 2 – 9 Stop Streaming
Excitation
EXON(?) c{,z}2 – 9 Excitation On/Off
Display& Configuration
DISX(?) {z}2 – 10 Display Enable/Disable
DTEM(?) {z}2 – 10 Display Temperature
FPLC(?) {i}2 – 10 Frequency of Power Line Cycle
Sensor Calibration
CINI(?) c{,z,s}2 – 10 Initialize Sensor Calibration
CAPT c,f,g 2 – 11 Add User Curve Point
CAPT? c,j 2 – 11 Query User Curve Point
CURV(?) c{,z}2 – 11 Select Sensor Curve
Serial Communications
BAUD(?) {i}2 – 11 Baud Rate
FLOW(?) {z}2 – 12 Flow Control
PARI(?) {z}2 – 12 Parity
Status
*CLS 2 – 12 Clear Status
*STB? [i]2 – 12 Status Byte
*SRE(?) [i,]{j}2 – 12 Service Request Enable
*ESR? [i]2 – 12 Standard Event Status
*ESE(?) [i,]{j}2 – 12 Standard Event Status Enable
SIM922 Diode Temperature Monitor

2.1 Index of Common Commands 2–3
CESR? [i]2 – 12 Communication Error Status
CESE(?) [i,]{j}2 – 13 Communication Error Status Enable
OVSR? [i]2 – 13 Overload Status
OVSE(?) [i,]{j}2 – 13 Overload Status Enable
PSTA(?) {z}2 – 13 Pulse −STATUS Mode
Interface
*RST 2 – 13 Reset
CONS(?) {z}2 – 13 Console Mode
*IDN? 2 – 14 Identify
*OPC(?) 2 – 14 Operation Complete
LEXE? 2 – 14 Execution Error
LCME? 2 – 15 Device Error
LDDE? 2 – 15 Device Error
LBTN? 2 – 15 Button
TOKN(?) {z}2 – 15 Token Mode
TERM(?) {z}2 – 16 Response Termination
SIM922 Diode Temperature Monitor

2–4 Remote Operation
2.2 Alphabetic List of Commands
?
*CLS 2 – 12 Clear Status
*ESE(?) [i,]{j}2 – 12 Standard Event Status Enable
*ESR? [i]2 – 12 Standard Event Status
*IDN? 2 – 14 Identify
*OPC(?) 2 – 14 Operation Complete
*RST 2 – 13 Reset
*SRE(?) [i,]{j}2 – 12 Service Request Enable
*STB? [i]2 – 12 Status Byte
B
BAUD(?) {i}2 – 11 Baud Rate
C
CAPT c,f,g 2 – 11 Add User Curve Point
CAPT? c,j 2 – 11 Query User Curve Point
CESE(?) [i,]{j}2 – 13 Communication Error Status Enable
CESR? [i]2 – 12 Communication Error Status
CINI(?) c{,z,s}2 – 10 Initialize Sensor Calibration
CONS(?) {z}2 – 13 Console Mode
CURV(?) c{,z}2 – 11 Select Sensor Curve
D
DISX(?) {z}2 – 10 Display Enable/Disable
DTEM(?) {z}2 – 10 Display Temperature
E
EXON(?) c{,z}2 – 9 Excitation On/Off
F
FLOW(?) {z}2 – 12 Flow Control
FPLC(?) {i}2 – 10 Frequency of Power Line Cycle
L
LBTN? 2 – 15 Button
LCME? 2 – 15 Device Error
LDDE? 2 – 15 Device Error
LEXE? 2 – 14 Execution Error
O
OVSE(?) [i,]{j}2 – 13 Overload Status Enable
SIM922 Diode Temperature Monitor