CONTROL CIRCUITS
14
ME00070B
TMS7 SERIES
Start signal
Output voltage
RELAY FUNCTIONS
Main contactor
Start/Run
Run
Pre-start Tests
Motor Thermistors
Motor thermistors (if installed in the motor) may be connected
directly to the TMS7. A trip will occur when the resistance of the
thermistor circuit exceeds approximately 2.8k
Ω
. The TMS7 can
be reset once the thermistor circuit resistance falls below
approximately 2.8k
Ω
Thermistor Input
C2
C1
No motor thermistors
C2
C1
Motor thermistors
Thermistor Input
CAUTION
NOTE:
The thermistor circuit must be closed before the
TMS7 will run.
The thermistor circuit should be run in screened
cable and must be electrically isolated from earth
and all other power and control circuits.
If no motor thermistors are connected to the TMS7
thermistor input there must be a link across the
thermistor input terminals C1 & C2.
6.4 RS485 Serial Communication
The TMS7 has a non-isolated RS485 serial communication link.
C5
C4
C3
RS485
GND
+
-
CAUTION
NOTE:
Power cabling should be kept at least 300mm away
from communications cabling. Where this cannot
be avoided magnetic shielding should be provided
to reduce induced common mode voltages.
Data transmitted to and from the TMS7 must be in 8 bit ASCII,
no parity, 1 stop bit.
Baud rate is set by Function. 61
RS485 Baud Rate
.
The TMS7 can be programmed to trip if the RS485 link fails by
setting Function 60.
RS485 Timeout.
The starter address is assigned using Function 62. RS485
Satellite Address
.
The flow charts below show typical form of communication
between an TMS7 and host controller.
Host controller to TMS7
START
SEND TMS7
SLAVE ADDRESS
ACK
RECEIVED
TIMEOUT
N
N
Y
Y
D
C
DATA/
COMMAND
SEND COMM AND
TIMEOUT
ACK
RECEIVED
Y
Y
N
N
N
Y
N
END
TIMEOUT
ERROR
LRC
ERROR
Y
N
Y
LRC
VALID
RECEIVE DATA
TIMEOUT
DATA
RECIEVED
SEND REQUEST
TMS7 to host controller
N
Y
N
Y
N
N
Y
Y
N
Y
N
Y
Y
N
N
Y
N
Y
N
Y
N
Y
START
EOT
DETECT
RECEIVE
ADDRESS
ENQ
EOT
L RC
VALI D
ADDRESS
VALI D
SEND ACK
STX
EOT
RECEIVE DATA
ETX
EOT
L RC
VALI D
SEND NAK
SEND
DATA
CONTROL TMS7
SEND DATA
SEND ACK
The following code sequences are used in the communications
between the host and the TMS7 (network).
Address slave unit.
ASCII EOT [nn]
LRC
ENQ
or
04h
[n1]h [n2]h
[LRC1]h [LRC2]h
05h
Slave response.
ASCII ACK
or
06h
