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FOR IMMEDIATE RELEASE
Instrument engineers guide to solving current loop problems
Signal isolators and loop interface 101
Omniflex Leaders in Signal Isolation and Loop Interface Solutions for Typical Plant Applications
The ubiquitous problem with every plant is the interface of plant measurement signals to the monitoring and control systems. Unfortunately for many plants this is the single biggest area of weakness and with the success of the organisation depending on these measurements, more attention should be afforded to the integrity of signal conditioning systems.
The problems faced by these systems are numerous:
* Aged cabling.
* Long cable runs.
* Earth loops.
* Interference from other plant devices.
* Floating earth potentials.
* Isolation of signals from PLC, SCADA and DCS.
* Legacy instrumentation.
* Isolate grounded equipment.
* Adding instruments to existing loops.
* Poor design.
* Converting current loops into accurate 1-5 V.
* Protecting against open circuit loops.
* Load dependency calibration.
A compendium of common problems is addressed using loop powered isolators (LPIs) in this two-part article.
In Part 1 four applications will be looked at and in Part 2 in next month's issue, a further six applications will be dealt with.
Application 1: Using the LPI to isolate a powered 4-20 mA transmitter output from a resistive load
This is the basic circuit for inserting a loop powered isolator into a current loop. The LPI can simply be 'cut' into any existing current loop to isolate the current transmitter from the load.
Note: The 'IN' side of the LPI is always connected to the side of the loop supplying the loop power.
The LPI will consume less than 3 V of the available loop voltage. This is equivalent to inserting less 150 Ω of additional resistance into the current loop.
To determine the maximum loop resistance that you can tolerate in your cabling, apply the following formula:
RMAX = RT - RL - 150
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
RT is the maximum load resistance that the current transmitter can drive (in Ω).
RL is the total resistance of all loads in the loop (excluding the LPI) (in Ω).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
Application 2: Using the LPI to isolate a field-mounted 4-20 mA two-wire transmitter from a PLC, RTU or DCS
This is the basic circuit for isolating a field-mounted two-wire transmitter from the control circuitry using an LPI. The LPI can simply be 'cut' into any existing two-wire current loop to isolate the transmitter from the panel power supply.
NOTE: The 'IN' side of the LPI is always connected to the side of the loop supplying the loop power, so in this application the two-wire transmitter is connected to the OUT terminals of the LPI.
Because of the 2 mm² wire size capability of the LPI terminals, the LPI can also act as the field interface terminals, saving you the extra termination and wiring cost. For multiple loops where space is a concern, use the LPD dual module. (See Applications 7, 8 and 9 in Part 2 of this article).
The LPI will consume less than 3 V of the available loop voltage. This is equivalent to inserting less 150 Ω of additional resistance into the current loop.
To determine the maximum loop resistance that you can tolerate in your cabling, apply the following formula:
In these cases you can use the internal resistor on the IN side of the LPI to conveniently convert your 4-20 mA signal into a 1-5 V signal. For the most accurate result, ensure that the 0 V reference of the LPI (terminal 8), and the 0 V reference of your analog input are referenced to the same point. Note: The 'IN' side of the LPI is always connected to the side of the loop supplying the loop power, so in this application the two-wire transmitter is connected to the OUT terminals of the LPI.Because of the 2 mm² wire size capability of the LPI terminals, the LPI can also act as the field interface terminals, saving you the extra termination and wiring cost.
The LPI will consume less than 3 V of the available loop voltage. This is equivalent to inserting less 150 Ω of additional resistance into the current loop.
To determine the maximum loop resistance that you can tolerate in your cabling in this application, apply the following formula:
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
VSmin is the minimum voltage of the power supply used to drive the loop (in V).
VTmin is the minimum voltage required by the two-wire transmitter for operation (in V).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
Application 4: Using the LPI's internal resistor with a four-wire transmitter to provide 1-5 V to your PLC/RTU/DCS
There are many cases when using 4-20 mA inputs to your PLC or RTU or DCS is inconvenient. For example:
There are cases, when using 4-20 mA inputs to your PLC, RTU or DCS, where it is important that the current loop is not disrupted when the analog input to your PLC or RTU or DCS is unplugged or disconnected.
In these cases you can use the internal clamp of the LPI to protect the loop from open circuit if your PLC or RTU or DCS input is unplugged or disconnected. This is simply achieved by connecting the input clamp terminal 3 to your 0 V reference. If the analog input to your PLC or RTU or DCS is disconnected, the current will be diverted to 0 V through the clamp, saving the current loop from disconnection.
The voltage across the LPI will be clamped to 6,8 V in this condition - only slightly higher than the normal operating voltage of 1-5 V. This higher clamp voltage should be used when calculating maximum allowable loop resistance.
Note: The 'IN' side of the LPI is always connected to the side of the loop supplying the loop power, so in this application the two-wire transmitter is connected to the OUT terminals of the LPI.
Because of the 2 mm2 wire size capability of the LPI terminals, the LPI can also act as the field interface terminals, saving you the extra termination and wiring cost.
To determine the maximum loop resistance of your cabling that you can tolerate in your loop with the clamp in operation, apply the following formula:
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
VSmin is the minimum voltage of the power supply used to drive the loop (in V).
VTmin is the minimum voltage required by the two-wire transmitter for operation (in V).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
Application 6: Using the LPI's internal clamp with a four-wire transmitter to protect the loop against open circuit
When using 4-20 mA inputs to your PLC, RTU or DCS, there are cases where it is important that the current loop is not disrupted when the analog input to your PLC or RTU or DCS is unplugged or disconnected.
Each LPD circuit will consume less than 3 V from the loop. For loop resistance calculation purposes this is equivalent to inserting an additional resistance of 150 Ω into the current loop.
Note: The 'IN' side of the LPD is always connected to the side of the loop supplying the loop power, and so in this application, the transmitter outputs are connected to the IN side of the LPD.
Because of the 2 mm2 wire size capability of the LPI terminals, the LPI can also act as the field interface terminals, saving you the extra termination and wiring cost.
To determine the maximum loop resistance of your cabling that you can tolerate in your loop, apply the following formula:
RMAX = RT - RL - 150
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
RT is the maximum load resistance that the current transmitter can drive (in Ω).
RL is the total resistance of all loads in the loop (excluding the LPI) (in Ω).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
Application 8: Using the LPD to isolate multiple 4-20 mA inputs to a PLC or RTU (with passive inputs)
In this application, the LPD can be inserted directly into the 4-20 mA input loops between the field-mounted two-wire transmitter and the PLC or RTU input.
Each LPD circuit will consume less than 3 V from the loop. For loop resistance calculation purposes this is equivalent to inserting an additional resistance of 150 Ω into the current loop.
Note: The 'IN' side of the LPD is always connected to the side of the loop supplying the loop power, and so in this application, the two-wire transmitters are connected to the OUT side of the LPD.
Because of the 2 mm2 wire size capability of the LPD terminals, the LPD can also act as the field interface terminals, saving you the extra termination and wiring cost.
To determine the maximum loop resistance of your cabling that you can tolerate in your loop, apply the following formula:
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
VSmin is the minimum voltage of the power supply used to drive the loop (in V).
VTmin is the minimum voltage required by the two-wire transmitter for operation (in V).
RL is the resistance of the PLC/RTU input (in Ω).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
Application 9: Using the LPD to isolate multiple 4-20 mA inputs to a DCS with active (two-wire tx) inputs
In this application, the LPD can be inserted directly into the 4-20 mA input loops between the field mounted two-wire transmitter and the DCS input.
Each LPD circuit will consume less than 3 V from the loop. For loop resistance calculation purposes this is equivalent to inserting an additional resistance of 150 Ω into the current loop.
Note: The 'IN' side of the LPD is always connected to the side of the loop supplying the loop power, and so in this application, the two-wire transmitters are connected to the OUT side of the LPD.
Because of the 2 mm2 wire size capability of the LPD terminals, the LPD can also act as the field interface terminals, saving you the extra termination and wiring cost.
To determine the maximum loop resistance of your cabling that you can tolerate in your loop, apply the following formula:
Back to PR Listing
* Aged cabling.
* Long cable runs.
* Earth loops.
* Interference from other plant devices.
* Floating earth potentials.
* Isolation of signals from PLC, SCADA and DCS.
* Legacy instrumentation.
* Isolate grounded equipment.
* Adding instruments to existing loops.
* Poor design.
* Converting current loops into accurate 1-5 V.
* Protecting against open circuit loops.
* Load dependency calibration.
A compendium of common problems is addressed using loop powered isolators (LPIs) in this two-part article.
In Part 1 four applications will be looked at and in Part 2 in next month's issue, a further six applications will be dealt with.
Application 1: Using the LPI to isolate a powered 4-20 mA transmitter output from a resistive load
This is the basic circuit for inserting a loop powered isolator into a current loop. The LPI can simply be 'cut' into any existing current loop to isolate the current transmitter from the load.
Application 1
Note: The 'IN' side of the LPI is always connected to the side of the loop supplying the loop power.
The LPI will consume less than 3 V of the available loop voltage. This is equivalent to inserting less 150 Ω of additional resistance into the current loop.
To determine the maximum loop resistance that you can tolerate in your cabling, apply the following formula:
RMAX = RT - RL - 150
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
RT is the maximum load resistance that the current transmitter can drive (in Ω).
RL is the total resistance of all loads in the loop (excluding the LPI) (in Ω).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
Application 2: Using the LPI to isolate a field-mounted 4-20 mA two-wire transmitter from a PLC, RTU or DCS
This is the basic circuit for isolating a field-mounted two-wire transmitter from the control circuitry using an LPI. The LPI can simply be 'cut' into any existing two-wire current loop to isolate the transmitter from the panel power supply.
Application 2
NOTE: The 'IN' side of the LPI is always connected to the side of the loop supplying the loop power, so in this application the two-wire transmitter is connected to the OUT terminals of the LPI.
Because of the 2 mm² wire size capability of the LPI terminals, the LPI can also act as the field interface terminals, saving you the extra termination and wiring cost. For multiple loops where space is a concern, use the LPD dual module. (See Applications 7, 8 and 9 in Part 2 of this article).
The LPI will consume less than 3 V of the available loop voltage. This is equivalent to inserting less 150 Ω of additional resistance into the current loop.
To determine the maximum loop resistance that you can tolerate in your cabling, apply the following formula:
- where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
VSmin is the minimum voltage of the power supply used to drive the loop (in V).
VTmin is the minimum voltage required by the two-wire transmitter for operation (in V).
RL is the total resistance of all loads in the loop (excluding the LPI) (in Ω).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
Application 3: Using the LPI's internal resistor with a two-wire transmitter to provide 1-5 V to your PLC/RTU/DCS
There are many cases when using 4-20 mA inputs to your PLC or RTU or DCS is inconvenient. For example:1. Your analog input does not support 4-20 mA, and mounting an external resistor is inconvenient.
2. Your analog input has plug in terminals, and you do not want to lose power to your field transmitter or disrupt the loop if the terminal block is unplugged.
Application 3
In these cases you can use the internal resistor on the IN side of the LPI to conveniently convert your 4-20 mA signal into a 1-5 V signal. For the most accurate result, ensure that the 0 V reference of the LPI (terminal 8), and the 0 V reference of your analog input are referenced to the same point. Note: The 'IN' side of the LPI is always connected to the side of the loop supplying the loop power, so in this application the two-wire transmitter is connected to the OUT terminals of the LPI.Because of the 2 mm² wire size capability of the LPI terminals, the LPI can also act as the field interface terminals, saving you the extra termination and wiring cost.
The LPI will consume less than 3 V of the available loop voltage. This is equivalent to inserting less 150 Ω of additional resistance into the current loop.
To determine the maximum loop resistance that you can tolerate in your cabling in this application, apply the following formula:
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
VSmin is the minimum voltage of the power supply used to drive the loop (in V).
VTmin is the minimum voltage required by the two-wire transmitter for operation (in V).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
Application 4: Using the LPI's internal resistor with a four-wire transmitter to provide 1-5 V to your PLC/RTU/DCS
There are many cases when using 4-20 mA inputs to your PLC or RTU or DCS is inconvenient. For example:
- Your analog input does not support 4-20 mA, and mounting an external resistor to convert the signal to 1-5 V is inconvenient.
- Your analog input has plug in terminals, and you do not want to lose power to your field transmitter or disrupt the loop if the terminals are unplugged.
Application 4
In these cases you can use the internal resistor on the OUT side of the LPI to conveniently convert your 4-20 mA signal into a 1-5 V signal.
For the most accurate result, ensure that the 0V reference to the LPI (terminal 5), and the 0V reference of your analog input are referenced to the same point.
Note: The 'IN' side of the LPI is always connected to the side of the loop supplying the loop power, so in this application the four-wire transmitter is connected to the IN terminals of the LPI.
Because of the 2 mm² wire size capability of the LPI terminals, the LPI can also act as the field interface terminals, saving you the extra termination and wiring cost.
The LPI will consume less than 8 V of the available loop voltage. This is equivalent to inserting less than 400 Ω of resistance into the current loop.
To determine the maximum loop resistance that you can tolerate in your cabling in this application, apply the following formula:
RMAX = RT - 400
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
RT is the maximum load resistance that the current transmitter can drive (in Ω).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
Application 5: Using the LPI's internal clamp with a two-wire transmitter to protect the loop against open circuit
There are cases, when using 4-20 mA inputs to your PLC, RTU or DCS, where it is important that the current loop is not disrupted when the analog input to your PLC or RTU or DCS is unplugged or disconnected.
Application 5
In these cases you can use the internal clamp of the LPI to protect the loop from open circuit if your PLC or RTU or DCS input is unplugged or disconnected. This is simply achieved by connecting the input clamp terminal 3 to your 0 V reference. If the analog input to your PLC or RTU or DCS is disconnected, the current will be diverted to 0 V through the clamp, saving the current loop from disconnection.
The voltage across the LPI will be clamped to 6,8 V in this condition - only slightly higher than the normal operating voltage of 1-5 V. This higher clamp voltage should be used when calculating maximum allowable loop resistance.
Note: The 'IN' side of the LPI is always connected to the side of the loop supplying the loop power, so in this application the two-wire transmitter is connected to the OUT terminals of the LPI.
Because of the 2 mm2 wire size capability of the LPI terminals, the LPI can also act as the field interface terminals, saving you the extra termination and wiring cost.
To determine the maximum loop resistance of your cabling that you can tolerate in your loop with the clamp in operation, apply the following formula:
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
VSmin is the minimum voltage of the power supply used to drive the loop (in V).
VTmin is the minimum voltage required by the two-wire transmitter for operation (in V).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
Application 6: Using the LPI's internal clamp with a four-wire transmitter to protect the loop against open circuit
When using 4-20 mA inputs to your PLC, RTU or DCS, there are cases where it is important that the current loop is not disrupted when the analog input to your PLC or RTU or DCS is unplugged or disconnected.
Application 6
In these cases you can use the internal clamp of the LPI to protect the loop from open circuit if your PLC or RTU or DCS input is unplugged or disconnected.
In four-wire current transmitter applications this is simply achieved by connecting the output clamp terminal 6 to the current output terminal 4 of the LPI. If the analog input to your PLC or RTU or DCS is disconnected, the current will be diverted through the clamp, saving the current loop from disconnection.
The voltage across the LPI will be clamped to 6,8 V in this condition - slightly higher than the normal operating voltage of 1-5 V. This higher clamp voltage should be used when calculating maximum allowable loop resistance.
Note: The 'IN' side of the LPI is always connected to the side of the loop supplying the loop power, so in this application the four-wire transmitter is connected to the IN terminals of the LPI.
Because of the 2 mm2 wire size capability of the LPI terminals, the LPI can also act as the field interface terminals, saving you the extra termination and wiring cost.
To determine the maximum loop resistance of your cabling that you can tolerate in your loop with the clamp in operation, apply the following formula:
RMAX = RT - 500
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
RT is the maximum load resistance that the current transmitter can drive (in Ω).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
For more information on the LPI, click here.
Application 7: Using the LPD to isolate multiple 4-20 mA outputs from a PLC or DCS
In this application, the LPD can be inserted directly into the 4-20 mA output loops between the transmitter and the load.
Application 7
Each LPD circuit will consume less than 3 V from the loop. For loop resistance calculation purposes this is equivalent to inserting an additional resistance of 150 Ω into the current loop.
Note: The 'IN' side of the LPD is always connected to the side of the loop supplying the loop power, and so in this application, the transmitter outputs are connected to the IN side of the LPD.
Because of the 2 mm2 wire size capability of the LPI terminals, the LPI can also act as the field interface terminals, saving you the extra termination and wiring cost.
To determine the maximum loop resistance of your cabling that you can tolerate in your loop, apply the following formula:
RMAX = RT - RL - 150
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
RT is the maximum load resistance that the current transmitter can drive (in Ω).
RL is the total resistance of all loads in the loop (excluding the LPI) (in Ω).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
Application 8: Using the LPD to isolate multiple 4-20 mA inputs to a PLC or RTU (with passive inputs)
In this application, the LPD can be inserted directly into the 4-20 mA input loops between the field-mounted two-wire transmitter and the PLC or RTU input.
Application 8
Each LPD circuit will consume less than 3 V from the loop. For loop resistance calculation purposes this is equivalent to inserting an additional resistance of 150 Ω into the current loop.
Note: The 'IN' side of the LPD is always connected to the side of the loop supplying the loop power, and so in this application, the two-wire transmitters are connected to the OUT side of the LPD.
Because of the 2 mm2 wire size capability of the LPD terminals, the LPD can also act as the field interface terminals, saving you the extra termination and wiring cost.
To determine the maximum loop resistance of your cabling that you can tolerate in your loop, apply the following formula:
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
VSmin is the minimum voltage of the power supply used to drive the loop (in V).
VTmin is the minimum voltage required by the two-wire transmitter for operation (in V).
RL is the resistance of the PLC/RTU input (in Ω).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
Application 9: Using the LPD to isolate multiple 4-20 mA inputs to a DCS with active (two-wire tx) inputs
In this application, the LPD can be inserted directly into the 4-20 mA input loops between the field mounted two-wire transmitter and the DCS input.
Application 9
Each LPD circuit will consume less than 3 V from the loop. For loop resistance calculation purposes this is equivalent to inserting an additional resistance of 150 Ω into the current loop.
Note: The 'IN' side of the LPD is always connected to the side of the loop supplying the loop power, and so in this application, the two-wire transmitters are connected to the OUT side of the LPD.
Because of the 2 mm2 wire size capability of the LPD terminals, the LPD can also act as the field interface terminals, saving you the extra termination and wiring cost.
To determine the maximum loop resistance of your cabling that you can tolerate in your loop, apply the following formula:
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
VSmin is the minimum voltage of the power supply used to drive the loop (in V).
VTmin is the minimum voltage required by the two-wire transmitter for operation (in V).
RL is the resistance of the PLC/RTU input (in Ω).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
For more information on the LPD, click here.
Application 10: Dealing with zero loop resistance when using the LPI
The LPI is optimised to minimise the effective inserted loop impedance, but does require a minimum of 100 Ω of load impedance, (or 2 V) on the output to maintain operation.
Application 10
In some applications, when using four-wire transmitters, the load being driven is lower than this minimum value, and additional load needs to be inserted into the output loop to bring the minimum load up to the required 100 Ω.
One solution for this is to use the internal 250 Ω resistor to provide this additional resistance. When connected as shown in the diagram, the internal resistor is used in series with the current loop to provide an additional 250 Ω of loop resistance. This brings the LPI back into specification without the need for any additional resistors.
Note: The 'IN' side of the LPI is always connected to the side of the loop supplying the loop power, so in this application the four-wire transmitter is connected to the IN terminals of the LPI.
Because of the 2 mm2 wire size capability of the LPI terminals, the LPI can also act as the field interface terminals, saving you the extra termination and wiring cost.
To determine the maximum loop resistance of your cabling that you can tolerate in your loop with the clamp in operation, apply the following formula:
RMAX = RT - RL - 400
where:
RMAX is the maximum resistance in the loop without causing measurement error (in Ω).
RT is the maximum load resistance that the current transmitter can drive (in Ω).
RL is the resistance of the connected load (in Ω).
For reliable operation over the long term, you should design for less initial cable resistance than this maximum value. This provides a safety factor to account for increase in resistance of terminations and wiring with age or weathering.
A sensible value to use for this safety factor would be 100 Ω (equal to 2 V at 20 mA).
For more information on the LPI, click here.
For more information contact Ian Loudon, Omniflex, +27 (0) 31 207 7466.
About Omniflex
Omniflex has accumulated over 50 years of experience in signal conditioning system design and has produced many innovative products in this particular field.
For further information on this press release please contact sales@omniflex.com