MM8TCISO

8 ISOLATED THERMOCOUPLE INPUTS

The MM8TCISO module is an 8 isolated thermocouple input module. The module uses differential inputs to reduce effects of electrical noise and mains pickup. The thermocouple inputs are isolated from the logic and from each other. This module is operated in an identical way to the MM8TC module and is fully interchangeable.

The thermocouple voltage is read by the module circuitry, linearised and converted to degrees Centigrade. No ranging is required as the module covers the full range. The value that is read from the Modbus register is the actual temperature in degrees centigrade to 0.1°C resolution. ie: a value of 3451 corresponds to a temperature of 345.1°C.

The thermocouple type is setup by writing a value to the TC Type register . The value is obtained from the table below. For example to select type K thermocouples, the value "2" must be written to the TC Type register. All 8 thermocouple inputs adopt the same TC type.

The DIP switch 9 is used to select upscale or downscale burnout. A value of 32768 is used to indicate upscale burnout and a value of -32767 is used to indicate downscale burnout.

The module has built in Cold Junction Compensation. Use must be made of the correct thermocouple extension wire to avoid reading errors.

The thermocouple module can also be configured for a 0 - 50mV input range. The TC Type register must be set to 9 for this option. The value in the register which is read back over the network is 0 - 50,000.

SPECIFICATIONS

Power Supply: Logic 10 - 26Vdc @ 80 mA

Inputs:

TC Type Range Accuracy

1 - J -200 to 760 °C 0.2°C

2 - K -200 to 1370 °C 0.3°C

3 - E 0 to 600 °C 0.1°C

4 - T -200 to 400 °C 0.3°C

5 - N 0 to 1300 °C 0.3°C

6 - B 400 to 1820 °C 0.5°C

7 - S -50 to 1767 °C 0.6°C

8 - R -50 to 1767 °C 0.7°C

9 - mV 0 to 50mV 0.1%

10 - C 0 to 2315.5 °C 0.7°C

11 - D 0 to 2315.5 °C 0.7°C

12 - G 0 to 2315.5 °C 0.9°C

Resolution 0.1°C

Drift 100ppm/°C Typ.

Isolation: 1000Vrms between field and logic
350Vpeak between each TC input

CJC error: ±0.5°C Typ.

Connector: 11 Pin Connector on rear of unit

18 Way screw connector on front

WIRING

SWITCH SETTINGS

SWITCH	FUNCTION	DESCRIPTION

1	NODE ID	Node ID’s from 0 to 127 are set up using switches 1 to 7.
2	NODE ID
3	NODE ID
4	NODE ID
5	NODE ID
6	NODE ID
7	NODE ID
8	-	Not used.
9	BREAK	TC break. When switched off the TC value will loaded with -32767 when the TC is faulty. When switched on the TC value will be loaded with 32768.
10	BAUD RATE	Selects 9600 (off) or 19200 BAUD (on)

DIAGNOSTIC UNIT MENU FORMAT

8 ISOLATED THERMOCOUPLE INPUTS

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