Cooper Instruments DFI-2555 User Manual

DFI 2555 SERIAL

COMMUNICATIONS GUIDE

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CONTENTS

SAFETY INSTRUCTIONS............................................................................................................1

1.0 INTRODUCTION TO OPERATION WITH COMPUTER OR TERMINAL...............................1

2.0 SERIAL INTERFACE: RS-232C OR RS-485.........................................................................1

2.1 Introduction to the Interface ..........................................................................................................1

2.2 Key data for the serial interface.....................................................................................................2

3.0 COMMUNICATION WITH THE DFI 2555 ..............................................................................2

3.1 Connect DFI 2555 and computer ...................................................................................................2

3.2 Activation of the RS232C or RS485 interface...............................................................................3

4.0 COMMAND SET OF THE INTERPRETER ............................................................................3

4.1 Important conventions ...................................................................................................................3

4.1.1 Command structure .................................................................................................................4

4.1.2 Data-output Structure ..............................................................................................................4

4.2 Description of Individual Commands............................................................................................5

4.2.1 Setting-up of functions in the additional functions group ................................................... 6

4.2.1.1 Setting of the RS232C interface parameters.......................................................................6

4.2.1.2 Setting of the RS485 interface parameters .........................................................................7

4.2.1.3 Querying for Device Identification/Firmware Status. ...........................................................8

4.2.1.4 Print functions .....................................................................................................................8

4.2.2 Setting-up of the Parameter-sets group................................................................................. 9

4.2.3 Define output format, measurement output ........................................................................11

4.2.3.1 Define output format.......................................................................................................... 11

4.2.3.2 Specify measurement output.............................................................................................12

4.2.4 Setting up the Adaptation group functions ......................................................................... 13

4.2.4.1 Setting up amplifier input................................................................................................... 13

4.2.4.2 Choose filter settings......................................................................................................... 14

4.2.4.3 Setting autocalibration....................................................................................................... 16

4.2.5 Setting up the Calibration group functions ......................................................................... 17

4.2.5.1 Selecting the unit of measure............................................................................................ 17

4.2.5.2 Selecting the indication upper limit....................................................................................18

4.2.5.3 Setting zero value..............................................................................................................19

4.2.5.4 Set measuring range.........................................................................................................19

4.2.5.5 Tare...................................................................................................................................20

4.2.6 Setting up the Limit Value 1...4 group functions.................................................................20

4.2.7 Setting up the functions of the Peak value store group.....................................................22

4.2.8 Setting up the functions of the Inputs/Outputs group........................................................ 23

4.2.8.1 Select amplifier input signal...............................................................................................23

4.2.8.2 Setting up the analog output .............................................................................................24

4.2.8.3 Setting up remote control ..................................................................................................25

4.2.8.4 Setting up assignment of the remotes............................................................................... 25

4.2.9 Setting up the Adaptation group functions ......................................................................... 26

4.2.9.1 Lock-control of the keys .................................................................................................... 26

5.0 ABBREVIATION/COMMAND INDEX ..................................................................................27

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SAFETY INSTRUCTIONS

The instrument complies with the safety requirements of DIN EN 61010, Part 1 (VDE 0411, Part 1); Protection
Class I. When connecting the instrument please adhere to the factory-set main voltage. This is shown on the rear
panel of the housing (230V/115V, 48...60Hz). Since the instrument is not fitted with its own mains switch, the power
cable must not be connected direct to the mains supply. According to VDE Guidelines it must be possible to
disconnect these instruments from the mains by means of a switching device (e.g. a mains switch).

1.0 INTRODUCTION TO OPERATION WITH COMPUTER OR TERMINAL

The DFI 2555 panel amplifier for panel-frame mounting (in accordance with DIN 43700) is suitable for recording
and processing measured data from passive transducers in the field of industrial test-facility engineering and
manufacturing-process monitoring.

Its main features are:

• Attachable transducers: SG full and half bridges, inductive full and half bridges, piezoresistive transducers,
LVDTs, potentiometers

• 10-character alphanumeric display

• Operation through touch-sensitive keypad; keys individually lockable

• 2 peak value stores for maximum and minimum values, also envelope and instantaneous value

• 4 limit monitors

• Parameter store for storing up to 8 data records

• Control I/Os (optocoupler-isolated)

This manual describes how to operate your DFI 2555 with a terminal or computer. It describes connection of a
computer via the RS232 for complete parameter input and scanning of measured data.

All steps required for setting up the instrument via the keypad, all information required for commissioning and all
menus are listed and described in a separate document, ”DFI 2555 User’s Guide”.

2.0 SERIAL INTERFACE: RS-232C OR RS-485

2.1 Introduction to the Interface

Through this serial interface data is transferred serially, one bit at a time. General properties are:

• Transmission speed relatively ”low”

• Requires in the simplest case a 3-core cable for bi-directional (duplex) transmission

• Only one device can be connected (point-to-point link)

Figure 1:Line level of the character Y with negative logic

A start bit is placed in front of each character (data byte). Then follow the data bits and a stop bit. Since data is
transferred sequentially, the speed of the transmitter must match that of the receiver. The number of bits per
second is termed the baud rate. A receiver’s exact baud rate is synchronized by the start bit for each byte
transmitted. Then follow the data bits, all of equal length. Once the stop bit has been reached, the receiver enters
its waiting state until reactivated by the next start bit. Data transmission is controlled by means of the software
handshake X-ON (DC1) and X-OFF (DC3). When the instrument is ready to transmit data, it sends the control
character X–ON (DC1) down the data line. If it cannot accept data, e.g. if its memory is full, the control character X–
OFF (DC3) is sent.

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2.2 Key data for the serial interface

Sampling rate 10 meas./s
Word length 8 bits
Stop bits 1*; 2
Parity odd, even* and none
Baud rate 300; 600; 1200; 2400; 4800; 9600*
* Factory setting

The interface configuration of the DFI 2555 (baud rate, parity and stop bit) must match that of the computer.

3.0 COMMUNICATION WITH THE DFI 2555

3.1 Connect DFI 2555 and computer

On the back of the instrument there is an RS232 serial interface for connecting a computer or terminal. For RS232
connection a connectorless cable (length 1.5m) and 9-pin subminiature socket* are supplied. Wiring and pin
assignment should be as illustrated below.

DFI 2555

Interface socket
on the DFI 2555

DFI 2555

*accessories

Figure 2: Computer / DFI 2555 connection

Figure 3: The RS485/422 bus with and without serial converter

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To connect the DFI 2555 to a computer proceed as follows:

• Connect both systems to the mains, leaving them switched off

• Connect the interface as shown in the diagram(s)

• The computer’s interface configuration (baud rate, data format) must match the DFI 2555’s basic setting. If it

does not, the interface configuration must be altered via the keypad (see DFI 2555 User’s Guide).

• Finally, switch both systems on.

When a printer is connected, a simple line printer operating at no more than 4 seconds per line is adequate. The
printout is in 12 columns. This corresponds to a line length of 132 characters.

3.2 Activation of the RS232C or RS485 interface

The Interpreter is activated by the following signal:
* CTRL R (DC2) computer operation without echo
Input of the control character puts the instrument into remote-operation mode; only the display’s output functions
can now be controlled. Computer operation without echo means that no command characters but only the data
generated are sent back to the DFI 2555. With the RS-232C interface each information-item generated is output as
soon as it is complete in the output buffer.

With the following command you can deactivate remote operation:
CTRL A (SOH); see also command DCL in Section 4.2.

4.0 COMMAND SET OF THE INTERPRETER

4.1 Important conventions

These conventions and general notes make working with the Interpreter’s commands easier for you.

Notation

• All commands can be input in lower or upper case.

Short commands

• Short commands consist of 3 to 5 characters and, depending on the command, a list of parameters separated
by commas.
e.g. BDR 6,2,1 (x)

Blanks

• Prefixed and following blanks in parameters are suppressed.

Command types

• Query commands – used for retrieving information – are identified by an added question mark (?)
e.g. BDR?

Responses

• The instrument’s responses given in the examples are shown in the User Manual in italics.

Command terminator

For input commands:

• (x) marks the command terminator. Permitted command terminators are: ”;”, LF, LFCR, CRLF

For output commands:

• (y) marks the command terminator. The command terminator is always CRLF.

I/O with numbers

• The numbers entered are changed to the relevant parameter’s numeric format

• Numbers are always output in fixed point format

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Serial interface

• With the RS232C interface, communication with a computer begins with the permitted control characters:

CTRL R or CTRL B and ends with CTRL A or the command DCL

• In the case of serial interfaces every command generates an output (response)

Acknowledgement

• Output commands – identified by a ? – always give rise to output data.

• Changing parameters

• If parameters affecting the measurement process itself are changed, calibration is performed after input; this

can take 1...3s.

Norms and standards

All commands used have a defined structure. There are essentially two types of command:

Set-up commands:

The DFI 2555 is set up through the computer.
Example: BDR6,2,1 (x)

0 (y)

The interface is set to 9600 baud, even parity and 1 stop bit.

Query commands:

Measured values or instrument settings are read from the
DFI 2555 and appear on the screen.
Example: BDR? (x)

6,2,1 (y)

The interface is set to 9600 baud, even parity and 1 stop bit.

4.1.1 Command structure

Short command Parameters End marker
TTT? p1,p2,...pn (x)
Example:
BDR? (x)
BDR Short commands as alphabetical characters (a...z)
? Only in query commands
p1,p2...pn Parameter values, consisting of sign (+/-) and numbers (0...9) or character strings (always in

quotation marks ” ”). A positive sign can be omitted.
, Separator
(x) Command terminator:

Line Feed (LF), Semi-colon (;) Carriage Return/Line Feed (CRLF) or Line Feed/Carriage

Return (LFCR)
CR ASCII characters: Carriage Return = decimal 13
LF ASCII characters: Line Feed = decimal 10
; ASCII characters: Semicolon = decimal 59

If an additional parameter - e.g. Parameter 2 - is omitted, at least the separator must be entered, e.g. ASA 1,,0(x)
If from a particular point all additional parameters are omitted, input can be concluded with the command
terminator.

4.1.2 Data-output Structure

q1,q2...qn (y)

Example 1:
IDN? (x)

HBM,MVD2555,0,P10 (y)

The responses sent by the DFI 2555 are printed in italics
q1,q2...qn Signed numerical values,

in this documentation (second line in the examples).

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Character strings (always in quotation marks) or ’?’ as an error message

; Separator
(y) End of sequence (CRLF)

4.2 Description of Individual Commands

On the following pages each command is listed, its structure analyzed and explained with an example.

Command

The character string that must be input to operate the instrument, e.g.:

BDR

Syntax

Mandatory notation for a command, e.g.:

BDR p1,p2,p3 (x)
BDR p1,,p3 (x)

Parameters

The meaning of any parameters is explained:
e.g. if for command ASA parameter p1=1, this means:
1V bridge excitation voltage

Effect

e.g. explanation of how the instrument is set up.

Response

The instrument responds to your input. In operation via terminal this response appears on the screen
(always in the case of output commands).

Example

The example shows you the command entered and the instrument’s response. The response is always
shown in italics.

Command
DCL Device Clear

Terminate communication
Syntax: DCL (x) or with RS232C/RS485 control character
CTRL A (ASCII code 01 decimal).
Parameters: none
Effect: Remote control operation is terminated.

Example: DCL(x)
Interpreter is no longer active.
Note:

ESR?
Output of the event-status register
Syntax: ESR? (x)
Parameters: none
Effect: Output of the contents of the standard event-status register (ESR) in decimal

q1 8, 16 or 32

Response: none

After this command you can input a new command only after approx. 3s.

Standard Event Status Register

equivalent.
The standard event-status register (ESR) is set if errors occur in communication.
Different causes of error set different bits, so that errors can be specified precisely.

Response: q1( y)

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All other bits are undefined.

4.2.1 Setting-up of functions in the additional functions group

4.2.1.1 Setting of the RS232C interface parameters

Command
BDR Baud rate

Syntax: BDR p1,p2,p3 (x)
Parameters:

Transmission is always carried out with a character length of 8 bits.
Effect: The serial interfaces’ baud rate, parity bit and number of stop-bits are reset.

Response:

Example: The DFI 2555 is being operated via the RS232C interface:

Command
BDR?

Output serial-interface parameters
Syntax: BDR?(x)
Parameters: none
Effect: The serial interface’s set baud rate, parity bit and number of stop bits are output.

Response: q1,q2,q3 (y)

Example: BDR? (x)

Setting of the RS232C parameters

p1 Baud rate

1 300
2 600
3 1200
4 2400
5 4800
6 9600

p2 Parity

0 None
1 Odd
2 Even

p3 Stop Bits

1 1 stop bit
2 2 stop bits

Acknowledgement Meaning

0 Command has been executed
? Error

BDR6,2,1 (x)

0 (y)

The RS232C interface has been set to 9600 baud, even parity and 1 stop bit.

Baud Rate Query

q1 Baud rate
q2 Parity
q3 Stop bits

6,2,1 (y)

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The interface has been set to 9600 baud, even parity and 1 stop bit.

4.2.1.2 Setting of the RS485 interface parameters

ADR Address

Assign RS485 address to the instrument
Syntax: ADR p1(x)
Parameters:

Effect: The command specifies the instrument’s RS485 address (see also command Sxx

on next page).

Response:

Acknowledgement Meaning

ADR? Address Query

Output the device address
Syntax: ADR?(x)
Parameters: none
Effect: Output the device address.

The RS485 address can be set using the command ADR or via the keypad in the
additional functions under COMM.ADR.

Response:

q1(y)

Command
Sxx

Select

Selects the DFI with the address xx
Syntax: S00(x) to S99(x)
Parameters: none
Effect: With the Select command

you can actuate individually up to 32 MGC devices

connected to one RS422/485 bus. There are 32 usable addresses 0...31. With the
Select command these addresses are mapped again on to addresses 32...63 and

64...95, i.e. the commands S00, S32, S64 actuate the devices with the address 00, but
their effect on them is not the same. Addresses 96...99 are provided for special
functions.

Address Sxx Device with the

specified address Sxx

Execute

Command
00…31 Yes Yes2) No No
32…63 Yes Yes2) Yes No1)
64…95 Yes No1) as for last address selected

96 No No No No

97,98 Yes No1) Yes No1)

993) Yes Yes2) Yes Yes2)

1) The response to the previous command is stored internally.

2) The stored response to the previous command is output subsequently.

3) Factory setting

Explanation:

S00...S31(x)
Only the instrument with the specified address receives commands, executes them and responds.

S32...S63(x)
All instruments receive all commands and execute them. Only the instrument with the specified address (S32 =
device 0) responds on behalf of all instruments.

p1 Device address

0…31

0 Command has been executed
? Error

q1 Device address

0…31

All other devices

Responses Execute

Responses

Command

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S64...S95(x)
The instrument with the specified address is accepted as a supplementary station that receives and executes all
commands but sends no responses.

S96(x)
All instruments wait for Select and send no responses.

S97 (x) or S98(x)
All instruments receive all commands and execute them, but send no responses.

S99(x)
All instruments on the bus are active, receive all commands and send responses (where there are multiple stations
this leads to collisions on the bus). Presetting of the devices after switching on (default).
Response: none
Example: S03(x)

Instrument with the address 03 executes all commands and responds.

S35(x)
All instruments on the bus receive and also execute all commands. Instrument with the address 03 (35-32)
responds on behalf of all instruments.

4.2.1.3 Querying for Device Identification/Firmware Status.

Command
AID?

Output of device identification
Syntax: AID?(x)
Parameters: none
Effect: Output of amplifier identification (firmware status)

Example: AID? (x)

Instruction
SNR? Serial Number

Output serial number of device
Syntax: SNR?
Parameter: None
Effect: Output of the serial number of the device

Response: Character string (10 characters)

Example: SNR? (x)

Response: Character string (20 characters)

Amplifier Identification Query

HBM,MVD2555,0,P15 (y)

Company, device designation, serial number, software version number

4021837410

4.2.1.4 Print functions

Command
PFS

Define print-format
Syntax: PFS p1 (x)
Parameters:

Effect: Signal to be printed is specified.

Print Format Select

p1 Signal to be printed

0 Value shown on the display
1 Gross value
2 Net value
4 Peak value1 (maximum)

8 Peak value2 (minimum)
16 Peak value3 (peak-to-peak)
63 All signals and status of limit values

You can set all signal-combinations by totaling the code numbers.

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