2
wire cannot form a circuit. As shown in the following figure
Error
Correct
4. Terminal Introduction
4.1 User terminal
MTCW-12-NT terminal silk screen
User terminal definition table
Remark
Description
24V+,24V-
Input power DC 24V
Ground
A0，B0
The first channel of RS485（COM0）
A1，B1
The second channel of RS485（COM1）
GND
The second channel of signal ground
WAN
Ethernet communication port
L1+～L16+
Channels 1 to 16 are positive for thermocouple
(thermal resistance) signal input
L1-～L16-
Channels 1 to 16 are negative for thermocouple
(thermal resistance) signal input
LR1-～LR16-
Channels 1 to 16 are negative for thermal
resistance signal input
Y01～Y04，COM0 Switch output port channel 1～4
Y05～Y08，COM1 Switch output port channel 5～8
Y09～Y12，COM2 Switch output port channel 9～12
Y13～Y16，COM3 Switch output port channel 13～16
VO1+～VO12+
The positive pole of the voltage output channel
1～12
VO1-～VO12-
The negative pole of the voltage output channel
1～12
CT1～CT8
The positive of current input signal channel 1～
8
CT-
The negative of current input signal channel 1～
8
Note
：
The output only one common terminal COM of MTCW-12-NT
and MTCW-08-TT.
4.2 User connection mode
5 things to pay attention to when wiring:
①
The thermocouple (thermal resistance) signal is recommended to be
accessed through the shielded cable (connection cable). Cables
should be kept away from power lines or other wires that may cause
electromagnetic interference. Using long cables (connecting cables) is
susceptible to noise interference. It is recommended to use cables less
than 100 meters in length (connecting cables). The cable (connecting
cable) has impedance, which will introduce measurement error. The
characteristic adjustment can solve this problem.
②
The thermal resistance must be connected by a three-wire system.
③
It is recommended that the positive and negative terminals of the
channel will not be used L+, L- short connection, in order to prevent the
channel will detect the wrong data.
④
If there is too much electrical interference, please connect the
shielding line (the compensation cable shielding end of thermocouple,
the cable shielding end of the thermal resistance connection, the
shielding end of the 485 communication line) with the thermostat
grounding end PG.
⑤
The thermostat grounding PGND should be good grounding.
5. Electrical indicator
5.1 Power indicator
Item
Unit
Min
value
Typical
value
Max
value
Remark
Input
voltage
range
Vdc
20
24
30
Normal start-up and
working range
Input
current
A
/
0.08
/
Normal temperature
rated full load
5.2 Performance indicators
Item
Indicator
CT input
Number of
input
channels
8
Measuring
current
range
AC0.4～50.0A(rms)(Peak current<71A, number
of turns :800, number of current through :1)
Allowable
max current
AC60A(rms) (Peak current<85A,number of
turns:800, number of current through:1)
Display
precision
Full scale ±5%
Display
resolution
0.1A
Note
：
The measurable current range is related to the number of turns
of the ct and the number of times the current passes through the CT.
