Impulse SCM9B-D100 User Manual

Isolated Intelligent Signal Conditioning Products

SCM9B-D100 Series

DIN Rail Mount Sensor-to-Computer Modules

Description

The SCM9B-D100 Sensor to Computer Modules are a family of data acquisition

modules that convert analog input signals to digital data and transmit via RS-485

to a controller which may be a computer or other processor-based equipment.

The modules can measure temperature, pressure, voltage, current, digital input

or digital output signals. The modules provide direct connection to a wide variety

of sensors and perform all signal conditioning, scaling, linearization and

conversion to either linearized ASCII data values or Modbus RTU data values.

Features such as address, baud rate, parity, echo, etc., are selectable using

simple commands over the RS-485 port. The selections are stored in nonvolatile

EEPROM which maintains data even after power is removed.

Data is acquired on a per channel basis so you only buy as many channels

as you need. The modules can be mixed and matched to fit your application.

They can be placed remote from the host and from each other. You can string

up to 247 modules on a twisted pair of wires by using RS-485 with repeaters.

All modules are supplied with screw terminal plug connectors. The connectors

allow system expansion, reconfiguration or repair without disturbing field wiring.

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Features

 Complete Sensor to RS-485 Interface

 500Vrms Analog Input Isolation

 15 Bit Measurement Resolution

 Continuous Self-Calibration; No Adjustments

of Any Kind

 Programmable Digital Filter

 Requires +5VDC Supply

 Transient Suppression on RS-485

Communications Lines

 Screw Terminal Plug Connectors Supplied

 CE Compliant

SCM9B

SCM9B

Utility software is available from Dataforth to make the D100 easier to learn and

use. The software is provided at no charge on request with a purchase order

and is not copy protected.

Theory Of Operation

Each Dataforth module is a complete single-channel data acquisition system.

Each unit contains analog signal conditioning circuits optimized for a specific

input type. Sensor signals are converted to digital data with a micro

processor-controlled integrating A/D converter. Offset and gain errors in the

analog circuitry are continuously monitored and corrected using microprocessor

techniques. The D100 converts the digital signal data and stores the resultant

data in a memory buffer. The modules continuously convert data at the rate of

8 conversions per second and store the latest result in the buffer.

Host processors may request data by sending a query to the module. The D100

will instantly respond by communicating the memory buffer data back to the host

processor. Up to 247 modules may be linked to a single RS-485 port. Each

module on a serial line is identified by a unique user-programmable address.

This addressing technique allows modules to be interrogated in any order.

Digital Inputs/Outputs

D170 digital input/output modules contain open-collector transistor switches that

may be controlled by the host processors. These switches may be used to

control solid-state relays which in turn may control heaters, pumps and other

power equipment. The digital inputs may be read by the host processor and

used to sense the state of remote digital signals. They are ideal for sensing the

state of limit or safety switches.

Command Set

The D100 series uses the Modbus RTU or the Dataforth ASCII protocol for

communication.

The Modbus RTU binary protocol uses a master-slave technique, in which only

the master device can initiate transactions. The slave devices respond by

supplying the requested data to the master or by taking the action requested

in the query. The master can address any slave device. The returned

messages are considered response messages. The supported master codes

are:

Modbus RTU Functions and Descriptions

01 Read Coil Status (Digital Inputs)

04 Read Input Register (Analog Inputs)

05 Force Single Coil (One Digital Input)

06 Preset Single Register (Dataforth/RTU Protocol)

15 Force Multiple Coils (Multiple Digital Output)

The Dataforth ASCII protocol is a command and response protocol using ASCII

characters for easy troubleshooting and interpretation of data values.

Digital Filter

The D100 analog input modules include two unique programmable single pole

digital filters. The filter is used to smooth analog data in noisy environments.

Separate time constants may be specified for small and large signal changes.

Typically a large time constant is specified for small signal changes to filter out

noise and provide stable output readings. A smaller time constant may be chosen

for large signal changes to provide fast response to such changes.

Visit our website www.dataforth.com

Figure 1: SCM9B-D100 Block Diagram

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Isolated Intelligent Signal Conditioning Products

SCM9B

D100 Series ASCII Command Set

Command and Definition Typical Typical

Command Response

Message Message

($ prompt)

DI Digital Input $1DI *0003

DO Digital Output $1DOFF *

RD Read Data $1RD *+00072.00

RS Read Setup $1RS *31070142

RSU Read Setup $1RSU *31070142

RZ Read Zero $1RZ *+00000.00

WE Write Enable $1WE *

Write Protected Commands

CZ Clear Zero $1CZ *

RR Remote Reset $1RR *

SU Setup Module $1SU31070142 *

TS Trim Span $1TS+00600.00 *

TZ Trim Zero $1TZ+00000.00 *

Specifications

Analog

 Single channel analog input.

 Maximum CMV, input to output at 60Hz: 500Vrms.



Leakage current, input to output at 115Vrms, 60Hz: <2µA rms.

 15 bit measurement resolution.

 8 conversions per second.

 Autozero & autocalibrationno adjustment pots.

Digital

 8-bit CMOS microcomputer.

 Digital scaling, linearization and calibration.

 Nonvolatile memory eliminates pots and switches.

Digital filtering

 Small and large signal with user selectable time

constants from 0 to 16 seconds.

Communications

 Communications in MODBUS-RTU via RS-485 ports.

 Selectable baud rates: 300, 600, 1200, 2400, 4800,

9600, 19200, 38400.

 NRZ asynchronous data format; 1 start bit, 8 data bits,

1 parity bit and 1 stop bit.

 Parity: odd, even, none.

 User selectable channel address.

 Up to 247 multidrop modules per host serial port.

 Communications distance up to 4,000 feet (RS-485).

 Transient suppression on RS-485 communications lines.

 All communications setups stored in EEPROM.

Power

 Requirements: Regulated +5VDC ,

 Protected against power supply reversals.

Environmental

 Temperature Range: Operating -25°C to +70°C.

 Relative Humidity: 0 to 95% noncondensing.

Typical at TA=+25°C and nominal power supply unless otherwise noted

0.75W max (DIN-150, 2.0W max.).

Storage -25°C to +85°C.

Setup

The D100 series are initiated at the factory using the Dataforth ASCII protocol.

This allows setup and configuration, including the Modbus device address, to

be easily performed using the Dataforth setup software or a dumb terminal. Each

D100 module must be properly configured before installation into a Modbus

system.

Utility Software

Complimentary Utility Software is included with each purchase order. The

software is compatible with Windows 95, 98, NT 4.0+, 2000 operating systems

and distributed on CD-ROM. The Utility Software simplifies configuration of all

user-selectable options such as device address, baud rate and filtering

constants.

Process Control Software

Modbus RTU protocol is supported by virtually all commercial process control

software programs available today. These programs operate on IBM and

compatible personal computers in the Windows 95, 98, NT and IBM OS/2

environments.

D11x Voltage Inputs

 Voltages: ±10mV, ±100mV, ±1V, ±5V, ±10V, ±100VDC.

 Resolution: 0.01% of FS (4 digits).

 Accuracy: ±0.02% of FS max.

 Common mode rejection: 100dB at 50/60Hz.

 Zero drift: ±1 count max (autozero).

 Span tempco: ±50ppm/°C max.

 Input burnout protection to 250VAC .

 Input impedance: ≤ ±1V input = 100MΩ min.

≥ ±5V input = 1MΩ min.

D125 Current Inputs

 Currents: 4-20mADC.

 Resolution: 0.04% of FS.

 Accuracy: 0.04% of FS.

 Common mode rejection: 100dB at 50/60Hz.

 Zero drift: ±1 count max (autozero).

 Span tempco: ±50ppm/°C max.

 Voltage drop: ±0.1V max.

D13x Thermocouple Inputs

 Thermocouple types: J, K, T, E, R, S, B, C (factory set).

 Ranges:

J = -200°C to +760°C B = 0°C to +1820°C

K = -150°C to +1250°C S = 0°C to +1750°C

T = -200°C to +400°C R = 0°C to +1750°C

E = -100°C to +1000°C C = 0°C to +2315°C

 Resolution: ±1°.

 Overall Accuracy (error from all sources) from 0 to +40°C

ambient: ±1.0 °C max (J, K, T, E).

±2.5 °C max (R, S, B, C)(300°C to FS).

 Common mode rejection: 100dB at 50/60Hz.

 Input impedance: 100MΩ min.
 Lead resistance effect: <20µV per 350Ω.

 Open thermocouple indication.

 Input burnout protection to 250VAC.

 Overrange indication.

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For information call 800-444-7644