27
buffer for MTC#3
buffer for MTC#7
3.2.5 Programming
This section through the "man-machine intPLC+MTC" this application system to explain the
general use of MTC thermostat. Taking MEGMEET series PLC as an example, ModBus is used for
communication between man-machine interface and PLC, and McBus is used for communication
between PLC and MTC. PLC station number is 0 and MTC station number is 1. 1. Set the parameters of
MTC. See chapter 4 for the MTC wizard Settings.
2. With the D and M components open to the user, PLC and man-machine interface can be used to
monitor and measure MTC. Let's expand on that.
Note: the D elements listed in table 3-2 and the dedicated M elements in the attachment are the
dedicated soft elements of the thermostat. Users are not allowed to use them for other purposes.
MTC provide some dedicated D and M components. For dedicated M components, users can operate
directly (see appendix I list of MCbus dedicated M components). For the D element, the user can operate
through the five command words described above.
Read command 4
1. The main module defines the frame with the MCbus communication buffer. D component definitions
are shown in the following table
Table 3-3 Settings represent communication special meaning D element
2. MTC thermostat return the frame with the MCbus communication buffer. Take MTC#1 region as an
example: when D7532 and D7563 become 4, data can be read from MTC, up to 30 D elements can be
read at a time, as shown in the following table.
Table 3-4 D component definitions 1
D elements
Explanation
D elements
Explanation
D7532
4
D7548
0
D7533
CH1 measured value (PV)
D7549
CH1 multi-step current
execution segment
D7534
CH2 measured value (PV)
D7550
CH2 multi-step current
execution segment
D7535
CH3 measured value (PV)
D7551
CH3 multi-step current
execution segment
D7536
CH4 measured value (PV)
D7552
CH4 multi-step current
execution segment
D7537
0
D7553
0
D7538
0
D7554
0
D7539
0
D7555
0
D7540
0
D7556
0
D7541
CH1 heat control output value
D7557
Cool control output status
D7542
CH2 heat control output value
D7558
0
D7500
D7501
D7502~7530
D7531
MTC module station
number to be read
4
Meaningless
Meaningless
