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titleSizing the System

Working out how many data loggers you require for a given installation is relatively simple.

  1. Count how many analogue and digital inputs are required

  2. Select the lowest cost data logger combination that satisfies these numbers of inputs:

SA380TX Hardware Variants

Configuration

Analogue Inputs

Digital Inputs

Base Unit (No Cards)

0

10

Base Unit + 1 Digital Card

0

18

Base Unit + 2 Digital Cards

0

26

Base Unit + 1 Analogue Cards

4

10

Base Unit + 2 Analogue Cards

8

10

Base Unit + 1 Analogue Card + 1 Digital Card

4

18

The SA380TX is more expensive than the SA380TX-L, it does however have advanced features, such as the touchscreen, battery back-up, advanced data processing options and master/slave capability.

SA380TX-L Hardware Variants

Configuration

Analogue Inputs

Digital Inputs

Base Unit (No Cards)

2

4

Base Unit + 1 Digital Card

2

12

Base Unit + 2 Digital Cards

2

20

Base Unit + 1 Analogue Cards

6

4

Base Unit + 2 Analogue Cards

10

4

Base Unit + 1 Analogue Card + 1 Digital Card

6

12

Master / Slave Devices

As stand-alone devices, each data logger will require an active SIM and GSM antenna in order to transmit data to the RADAR system. This can become troublesome for large installations installed in tight spaces.

Using a “Master / Slave” arrangement permits up to 7 SA380TX-L devices to connected over RS485.

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All data is marshalled through the master SA380TX device. Consequently all configuration, data collection and transmission, is controlled from the master SA380TX. In theory the maximum number analogue channels become 78, and digital channels becomes 166.

Note

The RS485 link can become overloaded when used for point monitoring if all the monitored point ends move concurrently. Mpec recommend the following limitations:

  • Electrically driven machines (Motor current only) 8 concurrent switch ends

  • Hydraulically driven machines (Motor current and pressure) 4 concurrent switch ends

Info

100 Ohm Resistors on RS485 lines are there to supress reflections.

  • These are required at each end of the link if the total link length exceeds 300m.

  • Fitment on shorter cable runs reduces signal to noise ratio, increasing the change of data corruption in the presence of noise.

The specification for the resistors is 100 to 120 Ohms. 5% tolerance or better, 1/4 Watt or better.

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titlePower & Earthing Arrangements

SA380TX

The power supply is internally isolated from earth and the rest of the SA380TX.

Power can therefore be taken directly from the signalling 110V supply and no additional isolating transformer is required.

The earth pin of the IEC C6 socket is not connected internally.  The unit must be earthed through its connection to the equipment racking.

The unit requires earthing for functional purposes (EMC ground). The unit does not require a protective earth connection in a rail environment.

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SA380TX-L

The power supply is internally isolated from earth and the rest of the SA380TX-L

Power can therefore be taken directly from the signalling 110V supply and no additional isolating transformer is required.

The earth pin of the mini-fit socket is connected internally.  The unit may be earthed through its connection to the equipment racking or through the power cable.

The unit requires earthing for functional purposes (EMC ground). The unit does not require a protective earth connection in a rail environment.

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