The simplified model of a motor is a resistor in series with an inductor and a voltage generator. The resistor and inductor are simply the resistance and inductance of the electromagnets inside the motor. The voltage generator represents the voltage that is created by the motor while it is turning and isreferred as Back EMF, or BEMF. The BEMF voltage is a fixed ratio of Volts per RPM.

Important notice: On many controller models, CAN and USB cannot be operated at the same time. Please see product datasheet to verify if this is the case on the model used. In case USB is not available, this section only applies to RS232 connections.
RoboCAN commands and queries can be sent from a USB or serial port using a modified syntax of the normal serial protocol: By simply adding the @ character followed by the node as a 2 digint hex address, a command or query is sent to the desired node. This scheme works with every Command (! Character), Query (?), Configuration setting (^), Configuration read (~), and most Maintenance commands (%)

Below is an Command example:
!G 1 500
This is the normal command for giving a 50% power level command to motor 1 of the controller that is attached to the computer.
@04G 1 500
This will send the same 50% command to motor 1 of the controller at node address 4.
The reply to a local command is normally a + or - sign when a command is acknowledged or rejected in normal serial mode.
When a command is sent to a remote node, the reply is also a + or – sign. However, in addition, the reply can be a * sign to indicate that the destination node does not exist or is not alive. Note that the + sign only indicates that the command syntax is valid and that the destination node is alive.

Node address 00 is used to broadcast a command simultaneously to all the nodes in the network. For example
@00!G 1 500
Will apply 50% power to all motor 1 at all nodes, including the local node

Queries are handled the same way but the reply to a query includes the responding node’s address. Below is a Query example:
?V 2
This is the normal query for reading the battery voltage of the local controller. The controller will reply V=123
@04?V 2
This will send the same query to node address 4
The reply of the remote node is @04 V=123
Replies to remote nodes queries are identical to these to a local controller with the exception of an added latency. Since the reply must be retrieved from the remote node depending on the selected bit rate, the reply may come up to 10ms after the query was sent.

Remote queries can only return a single value whereas local queries can be used to read an array of values. For example
?AI
Is a local query that will return the values of all analog capture channels in a single string as
AI=123:234:345:567
@04?AI
Is a remote query and it will return only the first analog capture channel as
@04 AI=123
Remote queries are not being added in the Query history.
Broadcasted remote queries are not supported. For example @00?V 1 will not be executed.
Queries that return strings, such as ?FID or ?TRN are not supported. They will return the value 0
See the Roboteq User Manual for the complete list and description of available queries

Configuration settings, like Amp Limit or Operating Modes can be read and changed on a remote node via the CAN bus. For example
@04^ALIM 1 250 will set the current limit of channel 1 of node 4 at 25.0A
@04~OVL will read the Overvoltage limit of node 4.
Note that changing a configuration via CAN only makes that change temporary until the remote controller is powered down. The %EESAV maintenance command must be send to the remote node to make the configuration change permanent.
A configuration write can be broadcast to all nodes simultaneously by using the node Id 00. For example
@00^OVL 250
Will set the overvoltage limit of all nodes at 25.0 Volts
Configuration reads cannot be broadcasted.
See Roboteq User Manual for the complete list and description of available configuration

top:
FetchCANValue(4, _C, 1) ' request data from remote node
while(IsCANValueReady() = false) ' wait until data is received
end while
Counter = ReadCANValue() ' read value
print (Counter, "\r") ' print value followed by new line
goto top ' repeat forever

' initiate scan of counter every 10ms from node 4 and store to buffer location 0
ScanCANValue(4, _C, 1, 10, 0)
' initiate scan of voltage every 100ms from node 4 and store to buffer location 1
ScanCANValue(5, _V, 1, 100, 1)

top:
wait(10) ' Executer loop every 10 ms
' check if scanned volts arrived
if(IsScannedCANReady(1))
   ' read and print volts
   Volts = ReadScannedCANValue(1)
   print (Volts,"\r")
end if

' No need to check if counter is ready since scan rate = loop cycle
Counter = ReadScannedCANValue(1)
print (Counter,"\r")
goto top ' Loop continuously