Go back  
Tools Request Product or Service Information Download Datasheet (acrobat pdf) Print This Page Email this Page to a Friend Magnify Primary Image Buy On-Line Now!  

Modbus & Serial Output Transmitter
for Load Cell or Microvolt Input

 Powers up to four 350 ohm load cells in parallel. DIN Rail mounted.
Digitally programmable. Exceptional accuracy at high update rates.

  
CE Mark      RoHS Mark
Made in California

Standard Features

  • 20, 50, 100, 250 & 500 mV full-scale ranges
  • 4 or 6-wire hookup to avoid supply and lead resistance effects
  • Isolated excitation output, 120 mA at 10V, to power up to four 350 ohm load cells in parallel
  • Digital span adjust from 0 to ±99,999
  • Digital zero adjust from -99,999 to +99,999
  • Accuracy to 0.01% of full scale.
  • RS232 or RS485 serial communications, half or full duplex, isolated
  • Modbus RTU, Modbus ASCII or Micron ASCII protocol
  • Output update rate to 60/sec
  • Easy setup with PC-based Instrument Setup Software
  • DIN rail mount housing only 22.5 mm wide
  • Detachable screw-clamp connectors
  • Dual solid state relays for alarm or control, isolated
  • 0-10V, 4-20 mA  or 0-20 mA  transmitter output, isolated
  • Universal AC power, 85-264 Vac
  • Priced Resonably (basic load cell transmitter)
    Options:
  • Extended main board for custom curve linearization & rate from successive readings
  • Low voltage power, 10-48 Vdc or 12-30 Vac

Description

The Micron Modbus & serial output, load cell or microvolt input transmitter is designed for use with load cells, strain gauges and microvolt input signals where exceptional sensitivity and stability are required. A most sensitive full-scale input range ±20 mV can be scaled internally to ±99,999 counts.

A built-in, isolated, 10V, 120 mA excitation supply can power up to four 350-ohm load cells in parallel. Load cell connection can be via 4 or 6 wires. With 4-wire load connection, the transmitter operates in a ratiometric mode to eliminate errors due to supply variations. With 6-wire load connection, it also compensates for variation in resistance of the transducer leads, thereby allowing long cable runs.

Fast read rate at up to 60 conversions per second while integrating the signal over a full power line cycle is provided by Concurrent Slope (Pat 5,262,780) analog-to-digital conversion. High read rate is ideal for peak or valley capture and for real-time computer interface and control.

Digital signal filtering modes are selectable for stable readings in electrically noisy environments. The internal digital readings and analog output can be separately selected to be either unfiltered or filtered.

  • An unfiltered selection updates after each conversion for fastest response, up to 60/sec, while integrating the input signal over a full power cycle. Fast read rate provides true peak and valley readings and aids in control applications.
  • A batch average filter selection averages each 16 conversions for an update every 1/4 sec.
  • An adaptive moving average filter selection provides a choice of 8 time constants from 80 ms to 9.6 s. When a significant change in signal level occurs, the filter adapts by briefly switching to the shortest time to follow the change, then reverts back to its selected time constant. Another choice is Auto, which provides an automatic time constant selection based on the signal noise characteristics.

LTM Series serial output transmitters send data via an isolated serial port, which is user configurable for RS232 or RS485 and full or half duplex operation. Three protocols are user selectable: Modbus RTU, Modbus ASCII, or Micron ASCII. Modbus operation is fully compliant with Modbus Over Serial Line Specification V1.0 (2002). The Micron ASCII protocol allows up to 31 Micron devices to be addressed on the same RS485 data line. It is simpler than the Modbus protocol and is recommended when all devices are Microns. It also allows use of Micron Datalogging Software.

Standard features of Micron transmitters include:

  • Serial data output, isolated. User selectable RS232 or RS485, half or full duplex, Modbus or Micron ASCII protocol.
  • Dual solid state relays for control or alarm, isolated. Rated 120 mA at 130 Vac or 170 Vdc.
  • Transducer excitation output, isolated. User selectable 5V@100 mA, 10V@120 mA or 24V@50 mA.
  • Analog transmitter output, 16-bit, user scalable and isolated. User selectable 4-20 mA, 0-20 mA or 0-10V levels.
  • Universal AC power supply for 85-264 Vac.

Easy Transmitter programming is via Micron's Instrument Setup Software, which runs on a PC under MS Windows. This software can be downloaded from this website at no charge. The required transmitter-to-PC interface cable is available from Micron (P/N CBL04).

Specifications
Micron Modbus & Serial I/O Transmitter for Load Cell or Microvolt Input

Analog Input
Range
Resolution
Input Ohms
Load Cell
 
 
 
 
±20.000 mV      
±50.0000 mV
±100.00 mV
±250.00 mV
±500.00 mV
-99,999 to +99,999
zero adjust.

0 to ±99,999
span adjust.
1 Gohm
Microvolt Meter
 
 
 
 
±20.000 mV 
±50.0000 mV
±100.00 mV
±250.00 mV
±500.00 mV
1 µV
2.5 µV
5.0 µV
12.5 µV
25 µV
1 Gohm
Input Resolution
Input Accuracy
Update Rate, Max
Max Applied Voltage
16 bits (65,536 steps)
±0.01% of full scale ± 2 counts
50/sec at 50 Hz, 60/sec at 60 Hz.
100 V
Transducer Excitation Output (standard)
Output levels
Output isolation
5V@100 mA, 10 @120 mA, 24V@50 mA (jumper selectable)
50V from signal ground
Serial Data Output (standard)
Signal Types
Data Rates
Output Isolation
Serial Protocols
Modbus Modes
Modbus Compliance
Digital Addressing
RS232 or RS485 (half or full duplex)
300, 600, 1200, 2400, 4800, 9600, 19200 baud
250V rms working, 2.3 kV rms per 1 min test
Modbus RTU, Modbus ASCII, Micron ASCII
RTU or ASCII
Modbus over Serial Line Specification V1.0 (2002)
247 Modbus addresses
Up to 32 devices on RS485 line w/o a repeater.
Dual Relay Output (standard)
Relay Type
Load rating
Two solid state relays, SPST, normally open, Form A
130 mA at 140 Vac or 180 Vdc
Analog Output (standard)
Output Levels
Compliance, 4-20 mA
Compliance, 0-10V
Output Resolution
Output Accuracy
Output Isolation
4-20 mA, 0-20 mA, 0-10 Vdc (jumper selectable)
10V ( 0-500 ohm load )
2 mA ( 5 kOhm load or higher)
16 bit DAC
±0.02% of output span plus conversion accuracy
250V rms working, 2.3 kV rms per 1 minute test
Power Input
Standard power
Low power option
Power frequency
Power isolation
Power consumption
85-264 Vac or 90-300 Vdc (DC operation not UL approved)
10-48 Vdc or 12-30 Vac
DC or 47-63 Hz
250V rms working, 2.3 kV rms per 1 min test
2W typical, 3W with max excitation output
Mechanical
Case Dimensions
Case Mounting
Electrical Connections
120 x 101 x 22.5 mm
35 mm rail per DIN EN 50022
Detachable screw-clamp plugs
Environmental
Operating Temperature
Storage Temperature
Relative Humidity
Protection
Cooling Required
0°C to 55°C
-40°C to 85°C
95% at 40°C, non-condensing
NEMA-4X (IP-65) when panel mounted
Mount transmitters so that ventilation holes are at top and bottom.
Leave 6 mm (1/4") between transmitters, or blow air by means of a fan.

Pinout
Micron Modbus & Serial Output Transmitter for Load Cell or Microvolt Input

For 4-wire load cell connection, jumper Pin 1 to Pin 2, and Pin 5 to Pin 6.

Load Cell Transmitter Connections
  

4-wire load cell bridge connection of a load cell transmitter
In 4-wire connection, the excitation and sense lines are tied together. The meter can make ratiometric corrections for supply voltage variations, but not compensate for variations in lead resistance. This connection is often used with short cable runs.

6-wire bridge connection of a load cell transmitter
In 6-wire connection, the sense lines are separate from the excitation lines, thereby eliminating effects due to variations in lead resistance. This allows long cable runs in outdoor environments with temperature extremes.

Up to six 350-ohm load cell bridges connected in parallel to a Laureate load cell transmitter
For large scales, up to four 350 ohm load cells in parallel can be powered by a single Micron transmitter at 5V excitation. The excitation and sense points of the four bridges are connected in parallel through a summing box.
Go back