Serial communication protocol between VFGL VFGLC elevator and access control system

1 Communication between the SMC-PROCON

1.1 Introduction

SMC is the access controller, PROCON is the protocol conversion device for the elevator to communicate with the access controller. This document defines the communication protocol between SMC and PROCON using RS-485 bus for communication.

1.2 Overview

The communication between SMC and PROCON is summArized as follows:
1) SMC sends a token to PROCON of each bank.
2) Whether SMC sends a data packet to PROCON or PROCON responds to SMC, it needs to wait for the token. (Data packet and token are used together)
3) After PROCON receives a data packet sent by SMC to its own group (excluding data packets sent to all groups), it sends 1 data packet to SMC (that is, it receives 1 data packet and responds to 1 data packet)
4) If SMC does not receive a response from PROCON, it considers PROCON to be faulty.
5) Data from SMC and PROCON are not sent repeatedly.

1.3 Basic Specifications

The basic specifications of SMC-PROCON communication are shown in Table 1-1.

Table 1-1 Basic specifications of SMC-PROCON communication

	project	specifications	remarks
1	Electrical character	RS-485
2	Number of nodes connected	MAX 9	SMC…1，PROCON…MAX8
3	Overall arrangement	Bus connection, half- duplex
4	Communication distance	1200 Meters
5	Data composition	Start bit (1 bit) Data bits (8 bits) Parity bit (1 bit even) Stop bit (1 bit)
6	Velocity	9600bps
7	Actual transfer speed (maximum)
8	Data volume(maximum)	30 bytes
9	Conflict avoidance	Token type	SMC-Primary (master)
10	Receive confirmation	not have
11	Data guarantee	Parity check per byte + checksum check per message
12	Failure detection		No normal message was received within the specified time.

1.4 Data Format

Note: For an empty packet, the length (LEN) is 0 and there is no data area (DATA).

Table 1-2 The SMC-PROCON communication code

Communication code	Content	Remarks
STX	Start code (02h)
BNK	Send / reply to the group group number
NOD	Node number within the group
LEN	DL
DATA	data	Up to 24 bytes
SUM	check sum
ETX	End code (03h)

① STX (start code)
Indicates the start of communication data. The setting value is 02h.

② BNK (send group number)
Indicates the send/response group number. The group number setting is shown in Table 1-3.

Table 1-3 Group numbers

Group number	cluster	Transfer direction
00h~07h	Group 1~8 (sending group)	SMC to PROCON
7F	All Groups	SMC to PROCON
80h~87h	Group 1~8 (Answer Group)	PROCON to SMC

Note: When sending to all groups, PROCON does not reply.

③ NOD (node in group)
Indicates the node number in the sending/replying group. The node number is shown in Table 1-4.

Table 1-4 Node number

Node number	Node	Remarks
01h	Group management	1，2
03h~0Ah	Machine #F~#D	*2
80h	PROCON	PROCON returns to SMC empty package
FFh	Group management, full-number machine	SMC to PROCON only

*1 In the case of a single elevator, two units are connected in parallel, the data comes from the group management module, and the sending node is #F to #D. The NOD returned by PROCON to SMC is 03h~0Ah, which is determined by the group management, not 01h.
*2 In the case of SMC to PROCON, the node number in the group. When the car card is swiped, NOD sends 03h~0Ah (#F to #D); when the floor station card is swiped, NOD must send 01h (group management). If there are multiple single elevators, different bank numbers are used to distinguish which elevator is called, because NOD always sends 01h.

④ LEN (length)
Indicates the data length, i.e. the data length in Figure 1-1, in bytes.

⑤ DATA (data)
Indicates the data body to be transmitted.

⑥ SUM (checksum)
Indicates the checksum, the calculation method of the checksum is: SUM= ~(BNK+NOD+LEN+DATA)+1.

⑦ ETX (end code)
Indicates the end of communication data, ETX is 03h.

1.5 Data transmission order

When SMC-PROCON communicates, the data transmission sequence is as follows:

① When the card is swiped, SMC sends the elevator control packet to PROCON. After the SMC data packet is sent, the next packet will not be sent before receiving the response from PROCON.
▲ When PROCON detects a minor fault, the next packet can be sent.
▲ When the whole group is in operation, the next packet can be sent without waiting for a response. (After the transmission is completed, the next packet will be sent after 10ms.)

② PROCON receives the data packet sent by SMC to its own group (including the whole group), and then sends the data packet to the elevator. If it is for its own data packet, it replies to SMC with the elevator status or an empty packet.
▲ Start responding within 10ms after receiving the data packet from SMC.
▲ No response is required for the whole group.

③ SMC receives the data packet from PROCON, processes the received data, and then sends the next packet. (Starts sending 10ms after receiving.)

④ When no event occurs, SMC sends empty data packets to PROCONs except for major faults in sequence.
▲ After SMC receives the data packet sent by PROCON, it can start sending new data packets to PROCON after 10ms.
▲ SMC does not send the next data packet if it does not receive a response from PROCON. (When PROCON has a minor fault, it can send the next data packet).
▲ When there is an event interruption, when it is idle again, it continues to send empty packets from the interruption point. Group 8 is followed by group 1. PROCONs with major faults are skipped.
▲ Skip when encountering a group that is not connected (building specifications do not exist).

⑤ When no event occurs, SMC sends a null packet to the seriously faulty PROCON every second.
▲ If there is no connected group (building specification does not exist), it will be skipped.

⑥PROCON receives the empty packet from SMC. If the elevator has a status packet, it returns the status packet to SMC. If not, it returns an empty packet to SMC.

1.6 Data transmission timing

The communication sequence between SMC and PROCON is shown in Table 1-5:

Table 1-5 DATA sending timing

project	price	remarks
Time interval between the data packets	Above 10ms, and within 20ms
The time interval between the bytes	0ms	Serial send
receive timeout	More than 5ms

*To ensure system response, the byte interval is 0, that is, data is sent continuously.
*During data packet reception, if the byte interval exceeds 5ms, this data packet is discarded and returns to the STX waiting state.

1.7 Fault Detectio

The fault detection of communication between SMC and PROCON is summarized as follows:

1.7.1 SMC fault detection

SMC sends a data packet to PROCON. PROCON does not respond within the specified time, and a PROCON fault is detected. The fault detection conditions are shown in Table 1-6.
When the communication cable is cut, all PROCON serious faults are detected.

Table 1-6 SMC fault detection conditions

Classify	Fault name	Discharge detection conditions	Troubleshooting conditions	Remarks
Individual failure	PROCON Light fault	PROCON The SMC packet was received and was not answered after 100ms	PROCON From SMC and respond within 100ms	The timeout period is the time from when SMC starts sending to when SMC receives the response data packet sent by PROCON.
Individual failure	PROCON Heavy fault	The above situation occurred 4 consecutive times	Ditto	Ditto

When PROCON has a minor fault, SMC can send the next data packet.
When PROCON has a major fault, SMC does not send the data packet when the card swipe event occurs. The card swipe event is discarded.
When no event occurs, an empty packet is sent to skip the PROCON with a major fault. However, an empty packet is sent to the PROCON with a major fault every 1 second.
When PROCON is normal, the maximum communication recovery time is 8 seconds.

1.7.2 PROCON Fault Detection

After receiving the data packet from PROCON, SMC fails to send it back within the specified time, and detects SMC fault. The fault detection conditions are shown in Table 1-7.

Table 1-7 PROCON fault detection conditions

Classify	Fault name	Discharge detection conditions	Troubleshooting conditions	Remarks
Individual failures	SMC failure	There is no communication between the SMC and any PROCON within 400ms.	SMC communicates with PROCON within 400ms	The timeout period refers to the time from the end of the last packet reception.

When SMC fails, the data sent by PROCON to the elevator side is discarded.
When SMC recovers, the old data is no longer sent.

2 Communication between SMC and elevator

2.1 Fault detection

2.1.1 SMC fault detection

SMC did not receive the elevator status returned by PROCON within the specified time and detected an elevator failure.

Table 2-8 SMC detects elevator faults

Classify	Fault name	Detection conditions	Eliminate conditions	Remarks
System fault detection	Elevator failure	No elevator status information from each group has been received for more than 4 seconds	Receive elevator status from each group

2.2 Elevator fault detection

The elevator (group management/group management module) did not receive the SMC heartbeat within the specified time and detected an SMC fault.

Table 2-9 Elevator SMC fault detection

Classify	Fault name	Detection conditions	Eliminate conditions	Remarks
System fault detection	SMC hitch	No SMC heartbeat was received for more than 20 seconds	Received a heartbeat from the SMC

3 Communication data

The SMC-elevator communication data is summarized as follows.

3.1 SMC->elevator communication data

3.1.1 Elevator control

(1) Swipe card at the landing (single floor)

NO	D7	D6	D5	D4	D3	D2	D1	D0
1	Command word: 0x01
2	Serial number: 0x00~0xFF
3	Card swipe location: floor 0, access control 1, home 2		Straight	Destination layer (rear)	Corresponding departure floor station button (0~7) 0x00——front door 0x01——back door
4	Take the elevator floor (0~127 management level)
5	Female	Kid	Elder	Administrator	VIP	Elevator call mode automatic: 0x00
6	Go to the destination floor (0~127 management level) FFh: All floors (administrators)

(2) Card swiping in the elevator (single floor)

NO	D7	D6	D5	D4	D3	D2	D1	D0
1	Command word: 0x09
2	Serial number: 0x00~0xFF
3	Preparation	Preparation	Straight	Destination layer (rear)	Preparation	Preparation	Control box properties (front door general 0; front door special 1; back door general 2; back door special 3)
4	Female	Kid	Elder	Administrator	VIP	Elevator call mode automatic: 0x00
5	Go to the destination floor (0~127 management level) FFh: All floors (administrator)
6	Preparation	Preparation	Preparation	Preparation	Preparation	Preparation	Preparation	Preparation

(3) Card swiping in the elevator (multiple floors)

NO	D7	D6	D5	D4	D3	D2	D1	D0
1	Command word: 0x09
2	Serial number: 0x00~0xFF
3	Preparation	Preparation	Straight	Preparation	Preparation	Preparation	Control box properties (front door general 0; front door special 1; back door general 2; back door special 3)
4	Female	Kid	Elder	Administrator	VIP	Elevator call mode automatic: 0x00
5	Rear door length				Front door length
6	Front door 7	Front door 6	Front door 5	Front door 4	Front door 3	Front door 2	Front door 1	Front door 0
7	Front door 15	Front door 14	Front door 13	Front door 12	Front door 11	Front door 10	Front door 9	Front door 8
8	Front door 23	Front door 22	Front door 21	Front door 20	Front door 19	Front door 18	Front door 17	Front door 16
9	Front door 31	Front door 30	Front door 29	Front door 28	Front door 27	Front door 26	Front door 25	Front door 24
10	Front door 39	Front door 38	Front door 37	Front door 36	Front door 35	Front door 34	Front door 33	Front door 32
11	Front door 47	Front door 46	Front door 45	Front door 44	Front door 43	Front door 42	Front door 41	Front door 40
12	Front door 55	Front door 54	Front door 53	Front door 52	Front door 51	Front door 50	Front door 49	Front door 48
13	Front door 63	Front door 62	Front door 61	Front door 60	Front door 59	Front door 58	Front door 57	Front door 56
14	Backdoor 7	Backdoor 6	Backdoor 5	Backdoor 4	Backdoor 3	Backdoor 2	Backdoor 1	Backdoor 0
15	Backdoor 15	Backdoor 14	Backdoor 13	Backdoor 12	Backdoor 11	Backdoor 10	Backdoor 9	Backdoor 8
16	Backdoor 23	Backdoor 22	Backdoor 21	Backdoor 20	Backdoor 19	Backdoor 18	Backdoor 17	Backdoor 16
17	Backdoor 31	Backdoor 30	Backdoor 29	Backdoor 28	Backdoor 27	Backdoor 26	Backdoor 25	Backdoor 24
18	Backdoor 39	Backdoor 38	Backdoor 37	Backdoor 36	Backdoor 35	Backdoor 34	Backdoor 33	Backdoor 32
19	Backdoor 47	Backdoor 46	Backdoor 45	Backdoor 44	Backdoor 43	Backdoor 42	Backdoor 41	Backdoor 40
20	Backdoor 55	Backdoor 54	Backdoor 53	Backdoor 52	Backdoor 51	Backdoor 50	Backdoor 49	Backdoor 48
21	Backdoor 63	Backdoor 62	Backdoor 61	Backdoor 60	Backdoor 59	Backdoor 58	Backdoor 57	Backdoor 56

3.1.2 Fault Detection

(1) SMC heartbeat

NO	D7	D6	D5	D4	D3	D2	D1	D0	Sending cycle 5s
1	Command word: 0x11
2	Preparation	Preparation	Preparation	Preparation	Preparation	Preparation	Preparation	Preparation
3	Preparation	Preparation	Preparation	Preparation	Preparation	Preparation	Preparation	Preparation

(2) Elevator status

NO	D7	D6	D5	D4	D3	D2	D1	D0	Sending cycle 1s
1	Command word: 0x11
2	#D	#C	#B	#A	#I	#H	#G	#F	Running 1, Stopping 0
3	Preparation	Preparation	Preparation	Preparation	Preparation	Preparation	Preparation	Preparation