GDM-8246 MULTIMETER |
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PROGRAMMER MANUAL |
CONTENTS |
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1. INTRODUCTION............................................................................. |
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2.CONNECTING DMM VIA GPIB INTERFACE……………... 2
3.CONNECTING DMM VIA RS232 INTERFACE……………. 5
4.INPUT AND OUTPUT QUEUE……………………………….. 8
5.COMMANDS AND SYNTAX…………………………………. 8
6.DETAILS OF COMMAND REFERENCE…………………… 21
7.STATUS AND ERROR REPORTING……………………….... 46
GDM-8246 MULTIMETER
PROGRAMMER MANUAL
1. INTRODUCTION
In the modern automatic measurement system, communication between equipments and computers is essential. The measured procedures can be varied with user’s testing programs, therefore, the Digital Multimeter can be operated remotely from an instrument controller or computer across the RS232 interface (optional) or GPIB (optional).
Interface selection and setup
Press [SHIFT][SET] in sequence into SET mode, then press [RS-232] or [GPIB] the white characters with blue background to set the RS232 OR GPIB interface. If the indicator of negative sine lights, the value displayed on the front panel is the current setting value. Use [▲][▼] can adjust the baud rate (or GPIB address). Finally, press [ENTER] to store the setup or press [SHIFT] to cancel the setup.
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GDM-8246 MULTIMETER
PROGRAMMER MANUAL
2.CONNECTING THE DIGITAL MULTIMETER VIA GPIB INTERFACE
The GPIB interface capabilities:
The GPIB interface of the Digital Multimeter corresponds to the standard of IEEE488.1-1987, IEEE488.2-1992 and SCPI-1994. The GPIB interface functions are listed as follows:
SH1(Source Handshake) |
: The DMM can transmit multilane |
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messages across the GPIB. |
AH1(Acceptor Handshake) |
: The DMM can receive multilane |
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messages across the GPIB. |
T6(Talker) |
: Talker interface function includes basic |
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talker, serial poll, and unaddress if MLA |
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capabilities, without talk only mode |
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function. |
L4 (Listener) |
: The DMM becomes a listener when the |
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controller sends its listen address with |
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the ATN (attention) line asserted. The |
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DMM does not have listen only |
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capability. |
SR1 (Service Request) |
: The DMM asserts the SRQ (Service |
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request) line to notify the controller |
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when it requires service. |
RL1 (Remote/Local) |
: The DMM responds to both the GTL(Go |
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to Local) and LLO(Local Lock Out) |
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interface messages. |
PP0 (Parallel Poll) |
: The DMM has no Parallel Poll interface |
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function. |
DC1 (Device Clear) |
: The DMM has Device clear capability to |
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return the device to power on status. |
DT0 (Device Trigger) |
: The DMM has no Device Trigger |
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interface function. |
C0 (Controller) |
: The DMM can not control other devices. |
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GDM-8246 MULTIMETER
PROGRAMMER MANUAL
Notes for GPIB installation
When the Digital Multimeter is set up with a GPIB system, please check the following things:
zOnly a maximum of 15 devices can be connected to a single GPIB bus.
zDo not use more than 20m of cable to connect devices to a bus.
zConnect one device for every 2m of cable used.
zEach device on the bus needs a unique device address. No two devices can share the same device address.
zTurn on at least two-thirds of the devices on the GPIB system while using the system.
zDo not use loop or parallel structure for the topology of GPIB system.
Computer’s Connection
A personal computer with a GPIB card is the essential facilities in order to operate the Digital Multimeter via GPIB interface.
The connections between DMM and computer are following:
I.Connect one end of a GPIB cable to the computer.
II.Connect the other end of the GPIB cable to the GPIB port on the Digital Multimeter.
Turn on the Digital Multimeter.
Turn on the computer.
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GDM-8246 MULTIMETER
PROGRAMMER MANUAL
The GPIB connection testing
If you want to test whether the GPIB connection is working or not, you can send a GPIB command from computer. For instance, the query command
*idn?
should return the Manufacturer, model number, and firmware version in the following format:
GW.Inc,GDM-8246,FW1.00
If you do not receive a proper response from the DMM, please check if the power is on, the GPIB address is correct, and all cable connections are active.
GDM-8246 MULTIMETER
PROGRAMMER MANUAL
3.CONNECTING THE DIGITAL MULTIMETER VIA RS232 INTERFACE
The RS232 interface capabilities:
The RS232 interface provides a point-to-point connection between two items of equipment such as a computer and the DMM. There are some parameters you need to set on the both sides. Once you have set these parameters, you can control the DMM through the RS232 interface.
zBaud rate: You can set rates of 1200, 2400, 4800 or 9600 baud.
zParity bit: none.
zData bit: 8 bits.
zStop bit: 1 stop bit.
zData flow control: none.
Notes for RS232 installation
The DMM is a DTE device with a 9-pin D-type shell RS232 connector located on the rear panel. Figure 1 shows the equipment of 9-pin connector (male) with its pin number assignments. Figure 2 shows the wiring configuration for DB9 to DB9. When the Digital Multimeter is set up with a RS232 interface, please check the following points:
zDo not connect the output line of one DTE device to the output line of the other.
zMany devices require a constant high signal on one or more input pins.
zEnsure that the signal ground of the equipment is connected to the signal ground of the external device.
zEnsure that the chassis ground of the equipment is connected to the chassis ground of the external device.
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GDM-8246 MULTIMETER
PROGRAMMER MANUAL
zDo not use more than 15m of cable to connect devices to a PC.
zEnsure the same baud rate is used on the device as the one used on PC terminal.
zEnsure the connector for the both side of cable and the internal connected line are met the demand of the instrument.
1.No connection
2. Receive Data(RxD) (input)
3.Transmit Data(TxD) (output)
4.No connection
5.Signal Ground(GND)
6.No connection
7.No connection
8.No connection
9.No connection
Figure 1 Pin assignments of the RS232 connector on the rear panel for DB-9-D
GDM-8246 MULTIMETER
PROGRAMMER MANUAL
EQUIPMENT |
COMPUTER |
(DB9, DTE) |
(DB9, DTE) |
Pin2 |
Pin2 |
Pin3 |
Pin3 |
Pin5 |
Pin5 |
Figure 2 Wiring configuration for DB9 to DB9
Computer’s Connection
A personal computer with a COM port is the essential facilities in order to operate the Digital Multimeter via RS232 interface.
The connections between DMM and computer are as follows:
I.Connect one end of a RS232 cable to the computer.
II.Connect the other end of the cable to the RS232 port on the Digital Multimeter.
III.Turn on the Digital Multimeter.
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Turn on the computer. |
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GDM-8246 MULTIMETER
PROGRAMMER MANUAL
The RS232 connection testing
If you want to test whether the RS232 connection is working or not, you can send a command from computer. For instance, using a terminal program send the query command
*idn?
should return the Manufacturer, model number, serial number and firmware version in the following format:
GW.Inc,GDM-8246,FW1.00
If you do not receive a proper response from the DMM, please check if the power is on, the RS232 baud rate are the same on both sides, and all cable connections are active.
4. INPUT AND OUTPUT QUEUE
The design of 128 bytes input queue and 128 bytes output queue for storing the pending commands or return messages is to prevent the transmitted commands of remote control and return messages from missing. As the maximum stored capacity for Error/Event Queue is 20 groups of messages, it should be noted that input data exceeding the capacity by using these buffers will cause data missing.
5. COMMANDS AND SYNTAX
The GPIB commands of the Digital Multimeter are compatible with IEEE-488.2 and SCPI standards
SCPI
SCPI (Standard Commands for Programmable Instruments) is a standard that created by an international consortium of the major test and measurement equipment manufacturers. The IEEE-488.2 syntax has been adopted by SCPI to provide common commands for the identical functions of different programmable instruments.
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GDM-8246 MULTIMETER
PROGRAMMER MANUAL
SCPI
Common Command & Queries
Syntax & Status Data Structure
Interface Function
D C B A A B C D
SCPI |
IEEE-488.1 |
SCPI |
IEEE-488.2 |
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IEEE-488.2 |
Figure 3 the relationship between IEEE-488.1, IEEE-488.2, and SCPI
As shown in the figure 3, the IEEE-488.1 standard locates at layer A, the layer A belongs to the protocol of interface function on the GPIB bus. The source handshake (SH), acceptor handshake (AH) and talker are included to this layer (10 interface functions totally).
At layer B, the syntax and data structure could be the essence of entire IEEE-488.2 standard. The syntax defines the function of message communication, which contain the <PROGRAM MESSAGE> (or simply “commands”) and <RESPONSE MESSAGE>. The two kinds of messages represent the syntax formation of device command and return value. The data structure is the constitution of status reporting, which IEEE-488.2 standard have been defined.
The common commands and queries are included to layer C. Commands and queries can be divided into two parts: mandatory and optional. Commands modify control settings or tell the instrument to perform a specific action. Queries cause the instrument to send data or status information back to the computer. A question mark at the end of a
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command identifies it as a query.
Layer D is interrelated with device information. Different devices have different functions. SCPI command sets belong to this layer.
Command Syntax
If you want to transfer any instructions to an instrument, and comply with SCPI, there are three basic elements must be included.
zCommand header
zParameter (if required)
zMessage terminator or separator
Command Header
The command header has a hierarchical structure that can be represented by a command tree (Figure 4).
The top level of the tree is the root level. A root node is located at the root level. A root node and one or more lower-level nodes form a header path to the last node called the leaf node.
The command header is configured by header path and leaf node. Figure 5 shows the command header for the leaf node indicated in Figure 4.
Figure 5 Command Header
Parameter
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If the commands have parameters, the values have to be included. In this |
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:SYSTem |
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Root node |
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manual, when we expressed the syntax of the command, the < > symbols |
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are used for enclosing the parameter type. For instance, the syntax of the |
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command in Figure 6 includes the Boolean parameter type. |
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NOTE: Do not include the <, >, or | symbols when entering the actual |
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value for a parameter. |
:ERRor |
:AUTO |
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Lower-level node |
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Leaf |
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:STATe |
:STARt |
:CYCLe |
Leaf Node |
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Figure 4: Tree hierarchy
Figure 6 Command Header with Parameter
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GDM-8246 MULTIMETER
PROGRAMMER MANUAL
Table 1 defines the Boolean and other parameter types for the Digital Multimeter.
Parameter Type |
Description |
Example |
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Boolean |
Boolean numbers or |
0, 1 |
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values |
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NR1 |
Integers |
0, 1, 18 |
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NR2 |
Decimal numbers |
1.5, 3.141, 8.4 |
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NR3 |
Floating point numbers |
4.5E-1, 8.25E+1 |
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String |
Alphanumeric characters |
“No error” |
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Table 1: Parameter Types for Syntax Descriptions
Message Terminator and Message Separator
I.GPIB message terminators
In accordance with IEEE 488.2 standard, any of the following message terminators are acceptable:
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LF^END |
Line feed code (hexadecimal 0A) with END |
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message |
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LF |
Line feed code |
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<dab>^END |
Last data byte with END message |
These terminators are compatible with most application programs. A semicolon separates one command from another when the commands appear on the same line.
GDM-8246 MULTIMETER
PROGRAMMER MANUAL
II.RS232 message terminators
As there is no signal of end message on RS232 bus, therefore, use LF as message terminator. When a series of commands are sent to the instrument, it must add a LF to be a judgment for message terminator. As for query command, the return message of the instrument is also added a LF for PC to judge message terminator.
Entering Commands
The standards that govern the command set for the Digital Multimeter allow for a certain amount of flexibility when you enter commands. For instance, you can abbreviate many commands or combine commands into one message that you send to the Digital Multimeter. This flexibility, called friendly listening, saves programming time and makes the command set easier to remember and use.
Command Characters
The DMM is not sensitive to the case of command characters. You can enter commands in either uppercase or lowercase.
You can execute any command with white space characters. You must, however, use at least one space between the parameter and the command header
Abbreviating Commands
Most commands have a long form and a short form. The listing for each command in this section shows the abbreviations in uppercase. For instance, you can enter the query :CONFigure:VOLTage:DC 0 simply as :CONF:VOLT:DC 0
Because the Digital Multimeter hypothesis that a command starts from the root, you have the option of beginning the initial command header with a colon (:).
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GDM-8246 MULTIMETER
PROGRAMMER MANUAL
Combining Commands
You can use a semicolon (;) to combine commands. But continuously query command will cause message missing. For example: :READ?;:VAL?
If the command that follows the semicolon has a different header path from the root level, you must use a colon to force a return to the root level:
:CONF:VOLT:DC 0;:CALC:SDBM:STAT 1
If the command that follows the semicolon has the same header path, you may omit the colon and the path and state only the new leaf node. For example:
:CONF:VOLT:DC 0;:CONF:CURR:DC 0 is equal to
:CONF:VOLT:DC 0;:CURR:DC 0
You can combine commands and queries into the same message. Note, for example, the following combination:
: CONF:VOLT:DC 0;:READ?
Synopsis of Commands
The tables in this section summarize the command of the Digital Multimeter. These tables divide the commands into four functional classifications:
zGeneral Setting Commands
zCalculating Commands.
zStatus Commands
zMiscellaneous Commands
The tables also provide a brief explanation of each command.
GDM-8246 MULTIMETER
PROGRAMMER MANUAL
zGeneral Setting Commands
Table 2 lists the general setting commands that control and query the settings of the DMM.
Table 2: General Setting Commands
Command |
Explanation |
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:CONFigure:AUTo? |
Returns Auto-range mode on or off. |
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:CONFigure:AUTo <Beolean> |
Sets Auto-range mode on or off. |
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:CONFigure:RANGe? |
Returns the range of the present |
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function. |
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:CONFigure:MODe? |
Returns the total value of the |
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selected calculation mode. |
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:CONFigure:FUNCtion? |
Returns the present selected |
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function. |
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:CONFigure:CAPacitance <NR2> |
Sets capacitance function and range. |
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:CONFigure:CONTinuity |
Sets continuity function. |
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:CONFigure:CURRent:AC <NR2> |
Sets AC current function and range. |
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:CONFigure:CURRent:DC <NR2> |
Sets DC current function and range. |
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:CONFigure:CURRent:ACDC <NR2> |
Sets AC+DC current function and |
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range. |
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:CONFigure:DIODe |
Sets diode function. |
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GDM-8246 MULTIMETER
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:CONFigure:SFRequency |
Sets frequency function. |
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:CONFigure:RESistance <NR2> |
Sets resistance function and range. |
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:CONFigure:VOLTage:AC <NR2> |
Sets AC voltage function and range. |
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:CONFigure:VOLTage:DC <NR2> |
Sets DC voltage function and range. |
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:CONFigure:VOLTage:ACDC <NR2> |
Sets AC+DC voltage function and |
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range. |
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:CONFigure:VOLTage:DCAC <NR2> |
Sets Ripple voltage function and |
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range. |
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:READ? |
Returns the value displayed on the |
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primary and secondary display |
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:VALue? |
Returns the value displayed on the |
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primary display. |
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:SVALue? |
Returns the value displayed on the |
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secondary display. |
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GDM-8246 MULTIMETER
PROGRAMMER MANUAL
z Calculation Commands
:CALCulation: LIMit:STATe? |
Returns Compare mode on or off. |
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:CALCulation: LIMit:STATe <Boolean> |
Sets Compare mode on or off. |
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:CALCulation: LIMit:LOWer? |
Returns the value of the lower |
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limit. |
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:CALCulation: LIMit:LOWer <NR2> |
Sets the value of the lower limit. |
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:CALCulation: LIMit:UPPer? |
Returns the value of the upper |
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limit. |
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:CALCulation: LIMit:UPPer <NR2> |
Sets the value of the upper limit. |
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:CALCulation: LIMit:FAIL? |
Returns the limit result. |
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:CALCulation:MAXimum? |
Returns the MAX mode on or |
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off. |
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:CALCulation:MAXimum <Boolean> |
Sets the MAX mode on or off. |
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:CALCulation:MINimum? |
Returns the MIN mode on or off. |
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:CALCulation:MINimum <Boolean> |
Sets the MIN mode on or off. |
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:CALCulation: RELation: STATe <NR1> |
Sets REL mode on or off. |
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:CALCulation:RELation: STATe? |
Returns REL mode on or off. |
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:CALCulation:RELation:DATa? |
Returns the reference value |
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the REL mode. |
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:CALCulation:RELation:DATa <NR2> |
Sets the reference value of |
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REL mode. |
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