Analog Inputs; Current And Voltage; Thermocouple; Resistance Thermometer (Rtd) - ABB SM1000 User Manual

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SM1000

5.4 Analog Inputs

5.4.1 Current and Voltage – Fig. 5.6
Warning.
When input 'Type' is set to 'Volts' (see Section 4.6.2,
page 74), input signals with voltages greater than 2V
(standard inputs) or 1V (high specification inputs)
be connected through an external voltage divider (part
no. GR2000/0375).
Input signals with voltages up to 2V (2000mV –
standard inputs) or 1V (1000mV – high specification
inputs) may be measured without the need for the
voltage divider by setting 'Type' to 'millivolts' – see
Section 4.6.2, page 74.
An external 10Ω shunt resistor is required for current
ranges.
To avoid damage to multi-channel instruments, high
common mode voltages up to 500V r.m.s. max. must
be present on all channels, or not at all.
For the standard input card the maximum channel-to-
channel voltage (between any two channels) must not
exceed 35V or permanent damage to the instrument's
input circuitry may occur. For applications requiring
higher levels of isolation refer to the high specification
card.
5.4.2 Thermocouple – Fig. 5.6
Use the correct compensating cable between the thermocouple
and the terminals – see Table 5.1 on page 102.
Automatic cold junction compensation (ACJC) is incorporated
but an independent cold (reference) junction may be used.
5.4.3 Resistance Thermometer (RTD) – Fig. 5.6
On applications requiring long leads it is preferable to use a 3-
lead resistance thermometer.
If 2-lead resistance thermometers are used, each input must be
calibrated to take account of the lead resistance.
5.4.4 Transmitter Power Supply – Fig. 5.7
Note. Two 24V power supplies are provided on the
transmitter power supply module boards, each of which is
capable of driving two 2-wire transmitters.
100
Voltage divider
must
(GR2000/0375)
required for
voltage inputs –
see Warnings
A – Voltage
+
–
3rd Lead
Each lead must be of equal
resistance and less than 10W
D – 3-lead RTD
F – Volt Free Digital Input (Standard Inputs)
G – Volt Free Digital Input (High Specification Inputs)
Fig. 5.6 Analog Input Connections
Warning. Under no circumstances must the spare input
terminal be linked to the negative.
Note. Refer also to Fig. 5.5 for terminal numbers.
Analog Input
+
–
Fig. 5.7 Transmitter Power Supply
+ +
–
–
10W Resistor supplied
in accessory pack.
B – Current C – Thermocouple
White
+
Red
–
Red
3rd Lead
E – 2-lead RTD
(and resistance)
Logic state
inactive
Logic state
inactive
Sleeved
Link
2-wire Transmitter Power Supply
(24V DC, 45mA max.)
–
+
Tx
+
–
10W Shunt
IM/SM1000 Issue 11
5 Installation
+
–
White
Red
Sleeved
Link
Logic state
active
Logic state
active