Functional Description
Original instructions
About us
Function
The BMX AMI 0810 is a high density input analog module with 8 isolated channels.
This module is used in conjunction with sensors or transmitters; it performs monitoring, measurement, and continuous process control functions.
The BMX AMI 0810 module offers the following range for each input according to the selection made during configuration:
The module operates with voltage inputs. It includes eight read resistors connected to the terminal block to perform current inputs.
Illustration
The BMX AMI 0810 illustration:
Description:
No.
Process
Function
1
Adapting the Inputs and Multiplexing
  • Physical connection to the process through a 28-pin screw terminal block
  • Protection of the module against overvoltages
  • Protection of the current reading resistors using limiters and resettable fuses
  • Input signal analog filtering
  • Scan input channels using static multiplexing through opto-switches, in order to provide the possibility of common mode voltage of +/- 300 Vdc
2
Amplifying Input Signals
  • Gain selecting , based on characteristics of input signals, as defined during configuration (unipolar or bipolar range, in voltage or current)
  • Compensation of drift in amplifier device
3
Converting
  • Conversion of analog Input signal into digital 24-bit signal using a ΣΔ converter
4
Transforming incoming values into workable measurements for the user.
  • Takes into account recalibration and alignment coefficients to be applied to measurements and the module's self-calibration coefficients
  • (Numeric) filtering fo measurements, based on configuration parameters
  • Scaling of measurements, based on configuration parameters
5
Communicating with the Application
  • Manages exchanges with CPU
  • Topological addressing
  • Receives configuration parameters from module and channels
  • Sends measured values, as well as module status, to application
6
Module monitoring and sending error notification back to application.
Conversion string test
Testing for range overflow on channels
Watchdog test
Measurement Timing
The timing of measurements is determined by the cycle selected during configuration (Normal or Fast Cycle):
The cycle time values are based on the cycle selected:
Module
Normal Cycle
Fast Cycle
BMX AMI 0810
9 ms
1 ms + (1 ms x N)
where N: number of channels in use.
NOTE: Module cycle is not synchronized with the PLC cycle. At the beginning of each PLC cycle, each channel value is taken into account. If the MAST/FAST task cycle time is less than the module's cycle time, some values will not have changed.
Overflow/Underflow Control
Module BMX AMI 0810 allows the user to select between 6 voltage or current ranges for each input.
This option for each channel have to be configured in configuration windows. Upper and lower tolerance detection are always active regardless of overflow/underflow control.
Depending on the range selected the module checks for overflow, it verifies that the measurement falls between a lower and an upper threshold:
Description:
Designation
Description
Nominal range
measurement range corresponding to the chosen range
Upper Tolerance Area
varies between the values included between the maximum value for the range (for instance: +10 V for the +/-10 V range) and the upper threshold
Lower Tolerance Area
varies between the values included between the minimum value for the range (for instance: -10 V for the +/-10 V range) and the lower threshold
Overflow Area
area located beyond the upper threshold
Underflow Area
area located below the lower threshold
The values of the thresholds are configurable independently from one another. They may assume integer values between the following limits:
Range
BMX AMI 0810 Range
Underflow Area
Lower Tolerance Area
Nominal Range
Upper Tolerance Area
Overflow Area
Unipolar
0...10 V
-1,500
-1,001
-1,000
-1
0
10,000
10,001
11,000
11,001
11,400
0...5 V /
0...20 mA
-5,000
-1,001
-1,000
-1
0
10,000
10,001
11,000
11,001
15,000
1...5 V /
4...20 mA
-4,000
-801
-800
-1
0
10,000
10,001
10,800
10,801
14,000
Bipolar
+/- 10 V
-11,500
-11,001
-11,000
-10,001
-10,000
10,000
10,001
11,000
11,001
11,400
+/- 5 V,
+/- 20 mA
-15,000
-11,001
-11,000
-10,001
-10,000
10,000
10,001
11,000
11,001
15,000
User
+/- 10 V
-32,768
User-defined
User-defined
32,767
0...10 V
-32,768
User-defined
User-defined
32,767
Measurement Display
Measurements may be displayed using standardized display (in %, to two decimal places):
Type of Range
Display
Unipolar range
0...10 V, 0...5 V, 1...5 V, 0...20mA, 4...20mA
from 0 to 10,000 (0 % at +100.00 %)
Bipolar range
+/- 10 V, +/- 5 mV +/- 20 mA
from -10,000 to 10,000 (-100.00 % at +100.00 %)
It is also possible to define the range of values within which measurements are expressed, by selecting:
The lower and upper thresholds must be integers between -32,768 and +32,767.
For example, imagine a conditioner providing pressure data on a 4-20 mA loop, with 4 mA corresponding to 3,200 millibar and 20 mA corresponding to 9,600 millibar. You have the option of choosing the User format, by setting the following lower and upper thresholds:
3,200 for 3,200 millibar as the lower threshold
9,600 for 9,600 millibar as the upper threshold
Values transmitted to the program vary between 3,200 (= 4 mA) and 9,600 (= 20 mA).
Measurement Filtering
The type of filtering performed by the system is called "first order filtering". The filtering coefficient can be modified from a programming console or via the program.
The mathematical formula used is as follows:
where:
α = efficiency of the filter
Measf(n) = measurement filtered at moment n
Measf(n-1) = measurement filtered at moment n-1
Valb(n) = gross value at moment n
You may configure the filtering value from 7 possibilities (from 0 to 6). This value may be changed even when the application is in RUN mode.
NOTE: Filtering may be accessed in Normal or Fast Cycle.
The filtering values depend on the T configuration cycle (where T =  cycle time of 5 ms in standard mode):
Desired Efficiency
Required Value
Corresponding α
Filter Response Time at 63%
Cut-off Frequency (in Hz)
No filtering
0
0
0
0
Low filtering
1
2
0.750
0.875
4 x T
8 x T
0.040 / T
0.020 / T
Medium filtering
3
4
0.937
0.969
16 x T
32 x T
0.010 / T
0.005 / T
High filtering
5
6
0.984
0.992
64 x T
128 x T
0.0025 / T
0.0012 / T
Sensor Alignment
The process of "alignment" consists in eliminating a systematic offset observed with a given sensor, around a specific operating point. This operation compensates for an error linked to the process. Replacing a module does not therefore require a new alignment. However, replacing the sensor or changing the sensor's operating point does require a new alignment.
Conversion lines are as follows:
The alignment value is editable from a programming console, even if the program is in RUN Mode. For each input channel, you can:
The alignment offset may also be modified through programming.
Channel alignment is performed on the channel in standard operating mode, without any effect on the channel's operating modes.
The maximum offset between measured value and desired (aligned) value may not exceed +/-1.500.
NOTE: To align several analog channels on the BMX ART/AMO/AMI/AMM modules, we recommand proceeding channel by channel. Test each channel after alignment before moving to the next channel in order to apply the parameters correctly.